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Bulletin of the Global Volcanism Network

All reports of volcanic activity published by the Smithsonian since 1968 are available through a monthly table of contents or by searching for a specific volcano. Until 1975, reports were issued for individual volcanoes as information became available; these have been organized by month for convenience. Later publications were done in a monthly newsletter format. Links go to the profile page for each volcano with the Bulletin tab open.

Information is preliminary at time of publication and subject to change.

Recently Published Bulletin Reports

Kuchinoerabujima (Japan) Eruption and ash plumes begin on 11 January 2020 and continue through April 2020

Soputan (Indonesia) Minor ash emissions during 23 March and 2 April 2020

Heard (Australia) Eruptive activity including a lava flow during October 2019-April 2020

Kikai (Japan) Ash explosion on 29 April 2020

Fuego (Guatemala) Ongoing ash explosions, block avalanches, and intermittent lava flows

Ebeko (Russia) Frequent moderate explosions, ash plumes, and ashfall continue, December 2019-May 2020

Piton de la Fournaise (France) Fissure eruptions in February and April 2020 included lava fountains and flows

Sabancaya (Peru) Daily explosions with ash emissions, large SO2 flux, ongoing thermal anomalies, December 2019-May 2020

Sheveluch (Russia) Lava dome growth and thermal anomalies continue through April 2020, but few ash explosions

Dukono (Indonesia) Numerous ash explosions continue through March 2020

Etna (Italy) Strombolian explosions and ash emissions continue, October 2019-March 2020

Merapi (Indonesia) Explosions produced ash plumes, ashfall, and pyroclastic flows during October 2019-March 2020



Kuchinoerabujima (Japan) — May 2020 Citation iconCite this Report

Kuchinoerabujima

Japan

30.443°N, 130.217°E; summit elev. 657 m

All times are local (unless otherwise noted)


Eruption and ash plumes begin on 11 January 2020 and continue through April 2020

Kuchinoerabujima encompasses a group of young stratovolcanoes located in the northern Ryukyu Islands. All historical eruptions have originated from the Shindake cone, with the exception of a lava flow that originated from the S flank of the Furudake cone. The most recent previous eruptive period took place during October 2018-February 2019 and primarily consisted of weak explosions, ash plumes, and ashfall. The current eruption began on 11 January 2020 after nearly a year of dominantly gas-and-steam emissions. Volcanism for this reporting period from March 2019 to April 2020 included explosions, ash plumes, SO2 emissions, and ashfall. The primary source of information for this report comes from monthly and annual reports from the Japan Meteorological Agency (JMA) and advisories from the Tokyo Volcanic Ash Advisory Center (VAAC). Activity has been limited to Kuchinoerabujima's Shindake Crater.

Volcanism at Kuchinoerabujima was relatively low during March through December 2019, according to JMA. During this time, SO2 emissions ranged from 100 to 1,000 tons/day. Gas-and-steam emissions were frequently observed throughout the entire reporting period, rising to a maximum height of 1.1 km above the crater on 13 December 2019. Satellite imagery from Sentinel-2 showed gas-and-steam and occasional ash emissions rising from the Shindake crater throughout the reporting period (figure 7). Though JMA reported thermal anomalies occurring on 29 January and continuing through late April 2020, Sentinel-2 imagery shows the first thermal signature appearing on 26 April.

Figure (see Caption) Figure 7. Sentinel-2 thermal satellite images showed gas-and-steam and ash emissions rising from Kuchinoerabujima. Some ash deposits can be seen on 6 February 2020 (top right). A thermal anomaly appeared on 26 April 2020 (bottom right). Sentinel-2 atmospheric penetration (bands 12, 11, 8A) images courtesy of Sentinel Hub Playground.

An eruption on 11 January 2020 at 1505 ejected material 300 m from the crater and produced ash plumes that rose 2 km above the crater rim, extending E, according to JMA. The eruption continued through 12 January until 0730. The resulting ash plumes rose 400 m above the crater, drifting SW while the SO2 emissions measured 1,300 tons/day. Ashfall was reported on Yakushima Island (15 km E). Minor eruptive activity was reported during 17-20 January which produced gray-white plumes that rose 300-500 m above the crater. On 23 January, seismicity increased, and an eruption produced an ash plume that rose 1.2 km altitude, according to a Tokyo VAAC report, resulting in ashfall 2 km NE of the crater. A small explosion was detected on 24 January, followed by an increase in the number of earthquakes during 25-26 January (65-71 earthquakes per day were registered). Another small eruptive event detected on 27 January at 0148 was accompanied by a volcanic tremor and a change in tilt data. During the month of January, some inflation was detected at the base on the volcano and a total of 347 earthquakes were recorded. The SO2 emissions ranged from 200-1,600 tons/day.

An eruption on 1 February 2020 produced an eruption column that rose less than 1 km altitude and extended SE and SW (figure 8), according to the Tokyo VAAC report. On 3 February, an eruption from the Shindake crater at 0521 produced an ash plume that rose 7 km above the crater and ejected material as far as 600 m away. As a result, a pyroclastic flow formed, traveling 900-1,500 m SW. The previous pyroclastic flow that was recorded occurred on 29 January 2019. Ashfall was confirmed in the N part of Yakushima Island with a large amount in Miyanoura (32 km ESE) and southern Tanegashima. The SO2 emissions measured 1,700 tons/day during this event.

Figure (see Caption) Figure 8. Webcam images from the Honmura west surveillance camera of an ash plume rising from Kuchinoerabujima on 1 February 2020. Courtesy of JMA (Weekly bulletin report 509, February 2020).

Intermittent small eruptive events occurred during 5-9 February; field observations showed a large amount of ashfall on the SE flank which included lapilli that measured up to 2 cm in diameter. Additionally, thermal images showed 5-km-long pyroclastic flow deposits on the SW flank. An eruption on 9 February produced an ash plume that rose 1.2 km altitude, drifting SE. On 13 February a small eruption was detected in the Shindake crater at 1211, producing gray-white plumes that rose 300 m above the crater, drifting NE. Small eruptive events also occurred during 20-21 February, resulting in gas-and-steam emissions that rose 200 m above the crater. During the month of February, some horizontal extension was observed since January 2020 using GNSS data. The total number of earthquakes during this month drastically increased to 1225 compared to January. The SO2 emissions ranged from 300-1,700 tons/day.

By 2 March 2020, seismicity decreased, and activity declined. Gas-and-steam emissions continued infrequently for the duration of the reporting period. The SO2 emissions during March ranged from 700-2,100 tons/day, the latter of which occurred on 15 March. Seismicity increased again on 27 March. During 5-8 April 2020, small eruptive events were detected, generating ash plumes that rose 900 m above the crater (figure 9). The SO2 emissions on 6 April reached 3,200 tons/day, the maximum measurement for this reporting period. These small eruptive events continued from 13-20 and 23-25 April within the Shindake crater, producing gray-white plumes that rose 300-800 m above the crater.

Figure (see Caption) Figure 9. Webcam images from the Honmura Nishi (top) and Honmura west (bottom) surveillance cameras of ash plumes rising from Kuchinoerabujima on 6 March and 5 April 2020. Courtesy of JMA (Weekly bulletin report 509, March and April 2020).

Geologic Background. A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km W of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. The youngest cone, centrally-located Shindake, formed after the NW side of Furudake was breached by an explosion. All historical eruptions have occurred from Shindake, although a lava flow from the S flank of Furudake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shindake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions.

Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Soputan (Indonesia) — May 2020 Citation iconCite this Report

Soputan

Indonesia

1.112°N, 124.737°E; summit elev. 1785 m

All times are local (unless otherwise noted)


Minor ash emissions during 23 March and 2 April 2020

Soputan is a stratovolcano located in the northern arm of Sulawesi Island, Indonesia. Previous eruptive periods were characterized by ash explosions, lava flows, and Strombolian eruptions. The most recent eruption occurred during October-December 2018, which consisted mostly of ash plumes and some summit incandescence (BGVN 44:01). This report updates information for January 2019-April 2020 characterized by two ash plumes and gas-and-steam emissions. The primary source of information come from the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) and the Darwin Volcanic Ash Advisory Center (VAAC).

Activity during January 2019-April 2020 was relatively low; three faint thermal anomalies were observed at the summit at Soputan in satellite imagery for a total of three days on 2 and 4 January, and 1 October 2019 (figure 17). The MIROVA (Middle InfraRed Observation of Volcanic Activity) based on analysis of MODIS data detected 12 distal hotspots and six low-power hotspots within 5 km of the summit during August to early October 2019. A single distal thermal hotspot was detected in early March 2020. In March, activity primarily consisted of white to gray gas-and-steam plumes that rose 20-100 m above the crater, according to PVMBG. The Darwin VAAC issued a notice on 23 March 2020 that reported an ash plume rose to 4.3 km altitude; minor ash emissions had been visible in a webcam image the previous day (figure 18). A second notice was issued on 2 April, where an ash plume was observed rising 2.1 km altitude and drifting W.

Figure (see Caption) Figure 17. Sentinel-2 thermal satellite imagery detected a total of three thermal hotspots (bright yellow-orange) at the summit of Soputan on 2 and 4 January and 1 October 2019. Sentinel-2 atmospheric penetration (bands 12, 11, 8A) images courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 18. Minor ash emissions were seen rising from Soputan on 22 March 2020. Courtesy of MAGMA Indonesia.

Geologic Background. The Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano is located SW of Riendengan-Sempu, which some workers have included with Soputan and Manimporok (3.5 km ESE) as a volcanic complex. It was constructed at the southern end of a SSW-NNE trending line of vents. During historical time the locus of eruptions has included both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Heard (Australia) — May 2020 Citation iconCite this Report

Heard

Australia

53.106°S, 73.513°E; summit elev. 2745 m

All times are local (unless otherwise noted)


Eruptive activity including a lava flow during October 2019-April 2020

Heard Island is located on the Kerguelen Plateau in the southern Indian Ocean and contains Big Ben, a snow-covered stratovolcano with intermittent volcanism reported since 1910. Due to its remote location, visual observations are rare; therefore, thermal anomalies and hotspots detected by satellite-based instruments are the primary source of information. This report updates activity from October 2019 to April 2020.

MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed three prominent periods of strong thermal anomaly activity during this reporting period: late October 2019, December 2019, and the end of April 2020 (figure 41). These thermal anomalies were relatively strong and occurred within 5 km of the summit. Similarly, the MODVOLC algorithm reported a total of six thermal hotspots during 28 October, 1 November 2019, and 26 April 2020.

Figure (see Caption) Figure 41. Thermal anomalies at Heard from 29 April 2019 through April 2020 as recorded by the MIROVA system (Log Radiative Power) were strong and frequent in late October, during December 2019, and at the end of April 2020. Courtesy of MIROVA.

Six thermal satellite images ranging from late October 2019 to late March showed evidence of active lava at the summit (figure 42). These images show hot material, possibly a lava flow, extending SW from the summit; a hotspot also remained at the summit. Cloud cover was pervasive during the majority of this reporting period, especially in April 2020, though gas-and-steam emissions were visible on 25 April through the clouds.

Figure (see Caption) Figure 42. Thermal satellite images of Heard Island’s Big Ben showing strong thermal signatures representing a lava flow in the SW direction from 28 October to 17 December 2019. These thermal anomalies are located NE from Mawson Peak. A faint thermal anomaly is also captured on 26 March 2020. Satellite images with atmospheric penetration (bands 12, 11, and 8A), courtesy of Sentinel Hub Playground.

Geologic Background. Heard Island on the Kerguelen Plateau in the southern Indian Ocean consists primarily of the emergent portion of two volcanic structures. The large glacier-covered composite basaltic-to-trachytic cone of Big Ben comprises most of the island, and the smaller Mt. Dixon lies at the NW tip of the island across a narrow isthmus. Little is known about the structure of Big Ben because of its extensive ice cover. The historically active Mawson Peak forms the island's high point and lies within a 5-6 km wide caldera breached to the SW side of Big Ben. Small satellitic scoria cones are mostly located on the northern coast. Several subglacial eruptions have been reported at this isolated volcano, but observations are infrequent and additional activity may have occurred.

Information Contacts: MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Kikai (Japan) — May 2020 Citation iconCite this Report

Kikai

Japan

30.793°N, 130.305°E; summit elev. 704 m

All times are local (unless otherwise noted)


Ash explosion on 29 April 2020

The Kikai caldera is located at the N end of Japan’s Ryukyu Islands and has been recently characterized by intermittent ash emissions and limited ashfall in nearby communities. On Satsuma Iwo Jima island, the larger subaerial fragment of the Kikai caldera, there was a single explosion with gas-and-steam and ash emissions on 2 November 2019, accompanied by nighttime incandescence (BGVN 45:02). This report covers volcanism from January 2020 through April 2020 with a single-day eruption occurring on 29 April based on reports from the Japan Meteorological Agency (JMA).

Since the last one-day eruption on 2 November 2019, volcanism at Kikai has been relatively low and primarily consisted of 107-170 earthquakes per month and intermittent white gas-and-steam emissions rising up to 1.3 km above the crater summit. Intermittent weak hotspots were observed at night in the summit in Sentinel-2 thermal satellite imagery and webcams, according to JMA (figures 14 and 15).

Figure (see Caption) Figure 14. Weak thermal hotspots (bright yellow-orange) were observed on 7 January (top) and 6 April 2020 (bottom) at Satsuma Iwo Jima (Kikai). Sentinel-2 satellite images with “Atmospheric penetration” (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 15. Incandescence at night on 10 January 2020 was observed at Satsuma Iwo Jima (Kikai) in the Iodake crater with the Iwanogami webcam. Courtesy of JMA (An explanation of volcanic activity at Satsuma Iwo Jima, January 2nd year of Reiwa [2020]).

Weak incandescence continued in April 2020. JMA reported SO2 measurements during April were 400-2000 tons/day. A brief eruption in the Iodake crater on 29 April 2020 at 0609 generated a gray-white ash plume that rose 1 km above the crater (figure 16). No ashfall or ejecta was observed after the eruption on 29 April.

Figure (see Caption) Figure 16. The Iwanogami webcam captured a brief gray-white ash and steam plume rising above the Iodake crater rim on Satsuma Iwo Jima (Kikai) on 29 April 2020 at 0609 local time. The plume rose 1 km above the crater summit. Courtesy of JMA (An explanation of volcanic activity at Satsuma Iwo Jima, April 2nd year of Reiwa [2020]).

Geologic Background. Kikai is a mostly submerged, 19-km-wide caldera near the northern end of the Ryukyu Islands south of Kyushu. It was the source of one of the world's largest Holocene eruptions about 6,300 years ago when rhyolitic pyroclastic flows traveled across the sea for a total distance of 100 km to southern Kyushu, and ashfall reached the northern Japanese island of Hokkaido. The eruption devastated southern and central Kyushu, which remained uninhabited for several centuries. Post-caldera eruptions formed Iodake lava dome and Inamuradake scoria cone, as well as submarine lava domes. Historical eruptions have occurred at or near Satsuma-Iojima (also known as Tokara-Iojima), a small 3 x 6 km island forming part of the NW caldera rim. Showa-Iojima lava dome (also known as Iojima-Shinto), a small island 2 km E of Tokara-Iojima, was formed during submarine eruptions in 1934 and 1935. Mild-to-moderate explosive eruptions have occurred during the past few decades from Iodake, a rhyolitic lava dome at the eastern end of Tokara-Iojima.

Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Fuego (Guatemala) — April 2020 Citation iconCite this Report

Fuego

Guatemala

14.473°N, 90.88°W; summit elev. 3763 m

All times are local (unless otherwise noted)


Ongoing ash explosions, block avalanches, and intermittent lava flows

Fuego is a stratovolcano in Guatemala that has been erupting since 2002 with historical eruptions that date back to 1531. Volcanism is characterized by major ashfalls, pyroclastic flows, lava flows, and lahars. The previous report (BGVN 44:10) detailed activity that included multiple ash explosions, ash plumes, ashfall, active lava flows, and block avalanches. This report covers this continuing activity from October 2019 through March 2020 and consists of ash plumes, ashfall, incandescent ejecta, block avalanches, and lava flows. The primary source of information comes from the Instituto Nacional de Sismologia, Vulcanología, Meteorología e Hidrologia (INSIVUMEH), the Washington Volcanic Ash Advisory Center (VAAC), and various satellite data.

Summary of activity October 2019-March 2020. Daily activity persisted throughout October 2019-March 2020 (table 20) with multiple ash explosions recorded every hour, ash plumes that rose to a maximum of 4.8 km altitude each month drifting in multiple directions, incandescent ejecta reaching a 500 m above the crater resulting in block avalanches traveling down multiple drainages, and ashfall affecting communities in multiple directions. The highest rate of explosions occurred on 7 November with up to 25 per hour. Dominantly white fumaroles occurred frequently throughout this reporting period, rising to a maximum altitude of 4.5 km and drifting in multiple directions. Intermittent lava flows that reached a maximum length of 1.2 km were observed each month in the Seca (Santa Teresa) and Ceniza drainages (figure 128), but rarely in the Trinidad drainage. Thermal activity increased slightly in frequency and strength in late October and remained relatively consistent through mid-March as seen in the MIROVA analysis of MODIS satellite data (figure 129).

Table 20. Activity summary by month for Fuego with information compiled from INSIVUMEH daily reports.

Month Ash plume heights (km) Ash plume distance (km) and direction Drainages affected by avalanche blocks Villages reporting ashfall
Oct 2019 4.3-4.8 km 10-25 km, W-SW-S-NW Seca, Taniluyá, Ceniza, Trinidad, El Jute, Honda, and Las Lajas Panimaché I and II, Morelia, Santa Sofía, Porvenir, Finca Palo Verde, La Rochela, San Andrés Osuna, Sangre de Cristo, and San Pedro Yepocapa
Nov 2019 4.0-4.8 km 10-20 km, W-SW-S-NW Seca, Taniluyá, Trinidad, Las Lajas, Honda, and Ceniza Panimaché I and II, Morelia, Santa Sofía, Porvenir, Sangre de Cristo, Finca Palo Verde, and San Pedro Yepocapa
Dec 2019 4.2-4.8 km 10-25 km, W-SW-S-SE-N-NE Seca, Taniluya, Ceniza, Trinidad, and Las Lajas Morelia, Santa Sofía, Finca Palo Verde, El Porvenir, Sangre de Cristo, San Pedro Yepocapa, Panimaché I and II, La Rochela, and San Andrés Osuna
Jan 2020 4.3-4.8 km 10-25 km, W-SW-S-N-NE-E Seca, Ceniza, Taniluyá, Trinidad, Honda, and Las Lajas Morelia, Santa Sofía, Sangre de Cristo, San Pedro Yepocapa, Panimaché I and II, El Porvenir, Finca Palo Verde, Rodeo, La Rochela, Alotenango, El Zapote, Trinidad, La Reina, Ceilán
Feb 2020 4.3-4.8 km 8-25 km, W-SW-S-SE-E-NE-N-NW Seca, Ceniza, Taniluya, Trinidad, Las Lajas, Honda, La Rochela, El Zapote, and San Andrés Osuna Panimache I and II, Morelia, Santa Sofia, Sangre de Cristo, San Pedro Yepocapa, Rodeo, La Reina, Alotenango, Yucales, Siquinalá, Santa Lucia, El Porvenir, Finca Los Tarros, La Soledad, Buena Vista, La Cruz, Pajales, San Miguel Dueñas, Ciudad Vieja, San Miguel Escobar, San Pedro las Huertas, Antigua, La Rochela, and San Andrés Osuna
Mar 2020 4.3-4.8 km 10-23 km, W-SW-S-SE-N-NW Seca, Ceniza, Trinidad, Taniluyá, Las Lajas, Honda, La Rochela, El Zapote, San Andrés Osuna, Morelia, Panimache, and Santa Sofia San Andrés Osuna, La Rochela, El Rodeo, Chuchu, Panimache I and II, Santa Sofia, Morelia, Finca Palo Verde, El Porvenir, Sangre de Cristo, La Cruz, San Pedro Yepocapa, La Conchita, La Soledad, Alotenango, Aldea la Cruz, Acatenango, Ceilan, Taniluyá, Ceniza, Las Lajas, Trinidad, Seca, and Honda
Figure (see Caption) Figure 128. Sentinel-2 thermal satellite images of Fuego between 21 November 2019 and 20 March 2020 showing lava flows (bright yellow-orange) traveling generally S and W from the crater summit. An ash plume can also be seen on 21 November 2019, accompanying the lava flow. Sentinel-2 satellite images with “Atmospheric penetration” (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 129. Thermal activity at Fuego increased in frequency and strength (log radiative power) in late October 2019 and remained relatively consistent through February 2020. In early March, there is a small decrease in thermal power, followed by a short pulse of activity and another decline. Courtesy of MIROVA.

Activity during October-December 2019. Activity in October 2019 consisted of 6-20 ash explosions per hour; ash plumes rose to 4.8 km altitude, drifting up to 25 km in multiple directions, resulting in ashfall in Panimaché I and II (8 km SW), Morelia (9 km SW), San Pedro Yepocapa (8 km NW), Sangre de Cristo (8 km WSW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, La Rochela and San Andrés Osuna. The Washington VAAC issued multiple aviation advisories for a total of nine days in October. Continuous white gas-and-steam plumes reached 4.1-4.4 km altitude drifting generally W. Weak SO2 emissions were infrequently observed in satellite imagery during October and January 2020 (figure 130) Incandescent ejecta was frequently observed rising 200-400 m above the summit, which generated block avalanches that traveled down the Seca (W), Taniluyá (SW), Ceniza (SSW), Trinidad (S), El Jute, Honda, and Las Lajas (SE) drainages. During 3-7 October lahars descended the Ceniza, El Mineral, and Seca drainages, carrying tree branches, tree trunks, and blocks 1-3 m in diameter. During 6-8 and 13 October, active lava flows traveled up to 200 m down the Seca drainage.

Figure (see Caption) Figure 130. Weak SO2 emissions were observed rising from Fuego using the TROPOMI instrument on the Sentinel-5P satellite. Top left: 17 October 2019. Top right: 17 November 2019. Bottom left: 20 January 2020. Bottom right: 22 January 2020. Courtesy of NASA Global Sulfur Dioxide Monitoring Page.

During November 2019, the rate of explosions increased to 5-25 per hour, the latter of which occurred on 7 November. The explosions resulted in ash plumes that rose 4-4.8 km altitude, drifting 10-20 km in the W direction. Ashfall was observed in Panimaché I and II, Morelia, Santa Sofía, Porvenir, Sangre de Cristo, Finca Palo Verde, and San Pedro Yepocapa. Multiple Washington VAAC notices were issued for 11 days in November. Continuous white gas-and-steam plumes rose up to 4.5 km altitude drifting generally W. Incandescent ejecta rose 100-500 m above the crater, generating block avalanches in Seca, Taniluyá, Trinidad, Las Lajas, Honda, and Ceniza drainages. Lava flows were observed for a majority of the month into early December measuring 100-900 m long in the Seca and Ceniza drainages.

The number of explosions in December 2019 decreased compared to November, recording 8-19 per hour with incandescent ejecta rising 100-400 m above the crater. The explosions generated block avalanches that traveled in the Seca, Taniluya, Ceniza, Trinidad, and Las Lajas drainages throughout the month. Ash plumes continued to rise above the summit crater to 4.8 km drifting up to 25 km in multiple directions. The Washington VAAC issued multiple daily notices almost daily in December. A continuous lava flow observed during 6-15, 21-22, 24, and 26 November through 9 December measured 100-800 m long in the Seca and Ceniza drainages.

Activity during January-March 2020. Incandescent Strombolian explosions continued daily during January 2020, ejecting material up to 100-500 m above the crater. Ash plumes continued to rise to a maximum altitude of 4.8 km, resulting in ashfall in all directions affecting Morelia, Santa Sofía, Sangre de Cristo, San Pedro Yepocapa, Panimaché I and II, El Porvenir, Finca Palo Verde, Rodeo, La Rochela, Alotenango, El Zapote, Trinidad, La Reina, and Ceilán. The Washington VAAC issued multiple notices for a total of 12 days during January. Block avalanches resulting from the Strombolian explosions traveled down the Seca, Ceniza, Taniluyá, Trinidad, Honda, and Las Lajas drainages. An active lava flow in the Ceniza drainage measured 150-600 m long during 6-10 January.

During February 2020, INSIVUMEH reported a range of 4-16 explosions per hour, accompanied by incandescent material that rose 100-500 m above the crater (figure 131). Block avalanches traveled in the Santa Teresa, Seca, Ceniza, Taniluya, Trinidad, Las Lajas, Honda, La Rochela, El Zapote, and San Andrés Osuna drainages. Ash emissions from the explosions continued to rise 4.8 km altitude, drifting in multiple directions as far as 25 km and resulting in ashfall in the communities of Panimache I and II, Morelia, Santa Sofia, Sangre de Cristo, San Pedro Yepocapa, Rodeo, La Reina, Alotenango, Yucales, Siquinalá, Santa Lucia, El Porvenir, Finca Los Tarros, La Soledad, Buena Vista, La Cruz, Pajales, San Miguel Dueñas, Ciudad Vieja, San Miguel Escobar, San Pedro las Huertas, Antigua, La Rochela, and San Andrés Osuna. Washington VAAC notices were issued almost daily during the month. Lava flows were active in the Ceniza drainage during 13-20, 23-24, and 26-27 February measuring as long as 1.2 km.

Figure (see Caption) Figure 131. Incandescent ejecta rose several hundred meters above the crater of Fuego on 6 February 2020, resulting in block avalanches down multiple drainages. Courtesy of Crelosa.

Daily explosions and incandescent ejecta continued through March 2020, with 8-17 explosions per hour that rose up to 500 m above the crater. Block avalanches from the explosions were observed in the Seca, Ceniza, Trinidad, Taniluyá, Las Lajas, Honda, Santa Teresa, La Rochela, El Zapote, San Andrés Osuna, Morelia, Panimache, and Santa Sofia drainages. Accompanying ash plumes rose 4.8 km altitude, drifting in multiple directions mostly to the W as far as 23 km and resulting in ashfall in San Andrés Osuna, La Rochela, El Rodeo, Chuchu, Panimache I and II, Santa Sofia, Morelia, Finca Palo Verde, El Porvenir, Sangre de Cristo, La Cruz, San Pedro Yepocapa, La Conchita, La Soledad, Alotenango, Aldea la Cruz, Acatenango, Ceilan, Taniluyá, Ceniza, Las Lajas, Trinidad, Seca, and Honda. Multiple Washington VAAC notices were issued for a total of 15 days during March. Active lava flows were observed from 16-21 March in the Trinidad and Ceniza drainages measuring 400-1,200 m long and were accompanied by weak to moderate explosions. By 23 March, active lava flows were no longer observed.

Geologic Background. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Information Contacts: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia (INSIVUMEH), Unit of Volcanology, Geologic Department of Investigation and Services, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala (URL: http://www.insivumeh.gob.gt/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS OSPO, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: www.ospo.noaa.gov/Products/atmosphere/vaac, archive at: http://www.ssd.noaa.gov/VAAC/archive.html); Crelosa, 3ra. avenida. 8-66, Zona 14. Colonia El Campo, Guatemala Ciudad de Guatemala (URL: http://crelosa.com/, post at https://www.youtube.com/watch?v=1P4kWqxU2m0&feature=youtu.be).


Ebeko (Russia) — June 2020 Citation iconCite this Report

Ebeko

Russia

50.686°N, 156.014°E; summit elev. 1103 m

All times are local (unless otherwise noted)


Frequent moderate explosions, ash plumes, and ashfall continue, December 2019-May 2020

The current moderate explosive eruption of Ebeko has been ongoing since October 2016, with frequent ash explosions that have reached altitudes of 1.3-6 km (BGVN 42:08, 43:03, 43:06, 43:12, 44:12). Ashfall is common in Severo-Kurilsk, a town of about 2,500 residents 7 km ESE, where the Kamchatka Volcanic Eruptions Response Team (KVERT) monitor the volcano. During the reporting period, December 2019-May 2020, the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

During December 2019-May 2020, frequent explosions generated ash plumes that reached altitudes of 1.5-4.6 km (table 9); reports of ashfall in Severo-Kurilsk were common. Ash explosions in late April caused ashfall in Severo-Kurilsk during 25-30 April (figure 24), and the plume drifted 180 km SE on the 29th. There was also a higher level of activity during the second half of May (figure 25), when plumes drifted up to 80 km downwind.

Table 9. Summary of activity at Ebeko, December 2019-May 2020. S-K is Severo-Kurilsk (7 km ESE of the volcano). TA is thermal anomaly in satellite images. In the plume distance column, only plumes that drifted more than 10 km are indicated. Dates based on UTC times. Data courtesy of KVERT.

Date Plume Altitude (km) Plume Distance Plume Directions Other Observations
30 Nov-05 Dec 2019 3 -- NE, E Intermittent explosions.
06-13 Dec 2019 4 -- E Explosions all week. Ashfall in S-K on 10-12 Dec.
15-17 Dec 2019 3 -- E Explosions. Ashfall in S-K on 16-17 Dec.
22-24 Dec 2019 3 -- NE Explosions.
01-02 Jan 2020 3 30 km N N Explosions. TA over dome on 1 Jan.
03, 05, 09 Jan 2020 2.9 -- NE, SE Explosions. Ashfall in S-K on 8 Jan.
11, 13-14 Jan 2020 3 -- E Explosions. Ashfall in S-K.
19-20 Jan 2020 3 -- E Ashfall in S-K on 19 Jan.
24-31 Jan 2020 4 -- E Explosions.
01-07 Feb 2020 3 -- E, S Explosions all week.
12-13 Feb 2020 1.5 -- E Explosions. Ashfall in S-K.
18-19 Feb 2020 2.3 -- SE Explosions.
21, 25, 27 Feb 2020 2.9 -- S, SE, NE Explosions. Ashfall in S-K on 22 Feb.
01-02, 05 Mar 2020 2 -- S, E Explosions.
08 Mar 2020 2.5 -- NE Explosions.
13, 17 Mar 2020 2.5 -- NE, SE Bursts of gas, steam, and small amount of ash.
24-25 Mar 2020 2.5 -- NE, W Explosions.
29 Mar-02 Apr 2020 2.2 -- NE, E Explosions. Ashfall in S-K on 1 Apr. TA on 30-31 Mar.
04-05, 09 Apr 2020 1.5 -- NE Explosions. TA on 5 Apr.
13 Apr 2020 2.5 -- SE Explosions.
18, 20 Apr 2020 -- -- -- TA on 18, 20 Apr.
24 Apr-01 May 2020 3.5 180 km SE on 29 Apr E, SE Explosions all week. Ashfall in S-K on 25-30 Apr.
01-08 May 2020 2.6 -- E Explosions all week. Ashfall in S-K on 3-5 May. TA on 3 May.
08-15 May 2020 4 -- E Explosions. Ashfall in S-K on 8-12 May. TA during 12-14 May.
14-15, 19-21 May 2020 3.6 80 km SW, S, SE during 14, 20-21 May -- Explosions. TA on same days.
22-29 May 2020 4.6 60 km SE E, SE Explosions all week. Ashfall in S-K on 22, 24 May.
29-31 May 2020 4.5 -- E, S Explosions. TA on 30 May.
Figure (see Caption) Figure 24. Photo of ash explosion at Ebeko at 2110 UTC on 28 April 2020, as viewed from Severo-Kurilsk. Courtesy of KVERT (L. Kotenko).
Figure (see Caption) Figure 25. Satellite image of Ebeko from Sentinel-2 on 27 May 2020, showing a plume drifting SE. Image using natural color rendering (bands 4, 3, 2) courtesy of Sentinel Hub Playground.

Geologic Background. The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS), 9 Piip Blvd., Petropavlovsk-Kamchatsky 683006, Russia (URL: http://www.kscnet.ru/ivs/eng/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Piton de la Fournaise (France) — May 2020 Citation iconCite this Report

Piton de la Fournaise

France

21.244°S, 55.708°E; summit elev. 2632 m

All times are local (unless otherwise noted)


Fissure eruptions in February and April 2020 included lava fountains and flows

Piton de la Fournaise is a massive basaltic shield volcano on the French island of Réunion in the western Indian Ocean. Recent volcanism is characterized by multiple fissure eruptions, lava fountains, and lava flows (BGVN 44:11). The activity during this reporting period of November 2019-April 2020 is consistent with the previous eruption, including lava fountaining and lava flows. Information for this report comes from the Observatoire Volcanologique du Piton de la Fournaise (OVPF) and various satellite data.

Activity during November 2019-January 2020 was relatively low; no eruptive events were detected, according to OVPF. Edifice deformation resumed during the last week in December and continued through January. Seismicity significantly increased in early January, registering 258 shallow earthquakes from 1-16 January. During 17-31 January, the seismicity declined, averaging one earthquake per day.

Two eruptive events took place during February-April 2020. OVPF reported that the first occurred from 10 to 16 February on the E and SE flanks of the Dolomieu Crater. The second took place during 2-6 April. Both eruptive events began with a sharp increase in seismicity accompanied by edifice inflation, followed by a fissure eruption that resulted in lava fountains and lava flows (figure 193). MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed the two eruptive events occurring during February-April 2020 (figure 194). Similarly, the MODVOLC algorithm reported 72 thermal signatures proximal to the summit crater from 12 February to 6 April. Both of these eruptive events were accompanied by SO2 emissions that were detected by the Sentinel-5P/TROPOMI instrument (figures 195 and 196).

Figure (see Caption) Figure 193. Location maps of the lava flows on the E flank at Piton de la Fournaise on 10-16 February 2020 (left) and 2-6 April 2020 (right) as derived from SAR satellite data. Courtesy of OVPF-IPGP, OPGC, LMV (Monthly bulletins of the Piton de la Fournaise Volcanological Observatory, February and April 2020).
Figure (see Caption) Figure 194. Two significant eruptive events at Piton de la Fournaise took place during February-April 2020 as recorded by the MIROVA system (Log Radiative Power). Courtesy of MIROVA.
Figure (see Caption) Figure 195. Images of the SO2 emissions during the February 2020 eruptive event at Piton de la Fournaise detected by the Sentinel-5P/TROPOMI satellite. Top left: 10 February 2020. Top right: 11 February 2020. Bottom left: 13 February 2020. Bottom right: 14 February 2020. Courtesy of NASA Global Sulfur Dioxide Monitoring Page.
Figure (see Caption) Figure 196. Images of the SO2 emissions during the April 2020 eruptive event at Piton de la Fournaise detected by the Sentinel-5P/TROPOMI satellite. Left: 4 April 2020. Middle: 5 April 2020. Right: 6 April 2020. Courtesy of NASA Global Sulfur Dioxide Monitoring Page.

On 10 February 2020 a seismic swarm was detected at 1027, followed by rapid deformation. At 1050, volcanic tremors were recorded, signaling the start of the eruption. Several fissures opened on the E flank of the Dolomieu Crater between the crater rim and at 2,000 m elevation, as observed by an overflight during 1300 and 1330. These fissures were at least 1 km long and produced lava fountains that rose up to 10 m high. Lava flows were also observed traveling E and S to 1,700 m elevation by 1315 (figures 197 and 198). The farthest flow traveled E to an elevation of 1,400 m. Satellite data from HOTVOLC platform (OPGC - University of Auvergne) was used to estimate the peak lava flow rate on 11 February at 10 m3/s. By 13 February only one lava flow that was traveling E below the Marco Crater remained active. OVPF also reported the formation of a cone, measuring 30 m tall, surrounded by three additional vents that produced lava fountains up to 15 m high. On 15 February the volcanic tremors began to decrease at 1400; by 16 February at 1412 the tremors stopped, indicating the end of the eruptive event.

Figure (see Caption) Figure 197. Photo of a lava flow and degassing at Piton de la Fournaise on 10 February 2020. Courtesy of OVPF-IPGP.
Figure (see Caption) Figure 198. Photos of the lava flows at Piton de la Fournaise taken during the February 2020 eruption by Richard Bouchet courtesy of AFP News Service.

Volcanism during the month of March 2020 consisted of low seismicity, including 21 shallow volcanic tremors and near the end of the month, edifice inflation was detected. A second eruptive event began on 2 April 2020, starting with an increase in seismicity during 0815-0851. Much of this seismicity was located on the SE part of the Dolomieu Crater. A fissure opened on the E flank, consistent with the fissures that were active during the February 2020 event. Seismicity continued to increase in intensity through 6 April located dominantly in the SE part of the Dolomieu Crater. An overflight on 5 April at 1030 showed lava fountains rising more than 50 m high accompanied by gas-and-steam plumes rising to 3-3.5 km altitude (figures 199 and 200). A lava flow advanced to an elevation of 360 m, roughly 2 km from the RN2 national road (figure 199). A significant amount of Pele’s hair and clusters of fine volcanic products were produced during the more intense phase of the eruption (5-6 April) and deposited at distances more than 10 km from the eruptive site (figure 201). It was also during this period that the SO2 emissions peaked (figure 196). The eruption stopped at 1330 after a sharp decrease in volcanic tremors.

Figure (see Caption) Figure 199. Photos of a lava flow (left) and lava fountains (right) at Piton de la Fournaise during the April 2020 eruption. Left: photo taken on 2 April 2020 at 1500. Right: photo taken on 5 April 2020 at 1030. Courtesy of OVPF-IPGP (Monthly bulletin of the Piton de la Fournaise Volcanological Observatory, April 2020).
Figure (see Caption) Figure 200. Photo of the lava fountains erupting from Piton de la Fournaise on 4 April 2020. Photo taken by Richard Bouchet courtesy of Geo Magazine via Jeannie Curtis.
Figure (see Caption) Figure 201. Photos of Pele’s hair deposited due to the April 2020 eruption at Piton de la Fournaise. Samples collected near the Gîte du volcan on 7 April 2020 (left) and a cluster of Pele’s hair found near the Foc-Foc car park on 9 April 2020 (right). Courtesy of OVPF-IPGP (Monthly bulletin of the Piton de la Fournaise Volcanological Observatory, April 2020).

Geologic Background. The massive Piton de la Fournaise basaltic shield volcano on the French island of Réunion in the western Indian Ocean is one of the world's most active volcanoes. Much of its more than 530,000-year history overlapped with eruptions of the deeply dissected Piton des Neiges shield volcano to the NW. Three calderas formed at about 250,000, 65,000, and less than 5000 years ago by progressive eastward slumping of the volcano. Numerous pyroclastic cones dot the floor of the calderas and their outer flanks. Most historical eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest caldera, which is 8 km wide and breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from fissures on the outer flanks of the caldera. The Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris, monitors this very active volcano.

Information Contacts: Observatoire Volcanologique du Piton de la Fournaise, Institut de Physique du Globe de Paris, 14 route nationale 3, 27 ème km, 97418 La Plaine des Cafres, La Réunion, France (URL: http://www.ipgp.fr/fr); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); GEO Magazine (AFP story at URL: https://www.geo.fr/environnement/la-reunion-fin-deruption-au-piton-de-la-fournaise-200397); AFP (URL: https://twitter.com/AFP/status/1227140765106622464, Twitter: @AFP, https://twitter.com/AFP); Jeannie Curtis (Twitter: @VolcanoJeannie, https://twitter.com/VolcanoJeannie).


Sabancaya (Peru) — June 2020 Citation iconCite this Report

Sabancaya

Peru

15.787°S, 71.857°W; summit elev. 5960 m

All times are local (unless otherwise noted)


Daily explosions with ash emissions, large SO2 flux, ongoing thermal anomalies, December 2019-May 2020

Although tephrochronology has dated activity at Sabancaya back several thousand years, renewed activity that began in 1986 was the first recorded in over 200 years. Intermittent activity since then has produced significant ashfall deposits, seismic unrest, and fumarolic emissions. A new period of explosive activity that began in November 2016 has been characterized by pulses of ash emissions with some plumes exceeding 10 km altitude, thermal anomalies, and significant SO2 plumes. Ash emissions and high levels of SO2 continued each week during December 2019-May 2020. The Observatorio Vulcanologico INGEMMET (OVI) reports weekly on numbers of daily explosions, ash plume heights and directions of drift, seismicity, and other activity. The Buenos Aires Volcanic Ash Advisory Center (VAAC) issued three or four daily reports of ongoing ash emissions at Sabancaya throughout the period.

The dome inside the summit crater continued to grow throughout this period, along with nearly constant ash, gas, and steam emissions; the average number of daily explosions ranged from 4 to 29. Ash and gas plume heights rose 1,800-3,800 m above the summit crater, and multiple communities around the volcano reported ashfall every month (table 6). Sulfur dioxide emissions were notably high and recorded daily with the TROPOMI satellite instrument (figure 75). Thermal activity declined during December 2019 from levels earlier in the year but remained steady and increased in both frequency and intensity during April and May 2020 (figure 76). Infrared satellite images indicated that the primary heat source throughout the period was from the dome inside the summit crater (figure 77).

Table 6. Persistent activity at Sabancaya during December 2019-May 2020 included multiple daily explosions with ash plumes that rose several kilometers above the summit and drifted in many directions; this resulted in ashfall in communities within 30 km of the volcano. Satellite instruments recorded SO2 emissions daily. Data courtesy of OVI-INGEMMET.

Month Avg. Daily Explosions by week Max plume Heights (m above crater) Plume drift (km) and direction Communities reporting ashfall Min Days with SO2 over 2 DU
Dec 2019 16, 13, 5, 5 2,600-3,800 20-30 NW Pinchollo, Madrigal, Lari, Maca, Achoma, Coporaque, Yanque, Chivay, Huambo, Cabanaconde 27
Jan 2020 10, 8, 11, 14, 4 1,800-3,400 30 km W, NW, SE, S Chivay, Yanque, Achoma 29
Feb 2020 8, 11, 20, 19 2,000-2,200 30 km SE, E, NE, W Huambo 29
Mar 2020 14, 22, 29, 18 2,000-3,000 30 km NE, W, NW, SW Madrigal, Lari, Pinchollo 30
Apr 2020 12, 12, 16, 13, 8 2,000-3,000 30 km SE, NW, E, S Pinchollo, Madrigal, Lari, Maca, Ichupampa, Yanque, Chivay, Coporaque, Achoma 27
May 2020 15, 14, 6, 16 1,800-2,400 30 km SW, SE, E, NE, W Chivay, Achoma, Maca, Lari, Madrigal, Pinchollo 27
Figure (see Caption) Figure 75. Sulfur dioxide anomalies were captured daily from Sabancaya during December 2019-May 2020 by the TROPOMI instrument on the Sentinel-5P satellite. Some of the largest SO2 plumes are shown here with dates listed in the information at the top of each image. Courtesy of NASA Global Sulfur Dioxide Monitoring Page.
Figure (see Caption) Figure 76. Thermal activity at Sabancaya declined during December 2019 from levels earlier in the year but remained steady and increased slightly in frequency and intensity during April and May 2020, according to the MIROVA graph of Log Radiative Power from 23 June 2019 through May 2020. Courtesy of MIROVA.
Figure (see Caption) Figure 77. Sentinel-2 satellite imagery of Sabancaya confirmed the frequent ash emissions and ongoing thermal activity from the dome inside the summit crater during December 2019-May 2020. Top row (left to right): On 6 December 2019 a large plume of steam and ash drifted N from the summit. On 16 December 2019 a thermal anomaly encircled the dome inside the summit caldera while gas and possible ash drifted NW. On 14 April 2020 a very similar pattern persisted inside the crater. Bottom row (left to right): On 19 April an ash plume was clearly visible above dense cloud cover. On 24 May the infrared glow around the dome remained strong; a diffuse plume drifted W. A large plume of ash and steam drifted SE from the summit on 29 May. Infrared images use Atmospheric penetration rendering (bands 12, 11, 8a), other images use Natural Color rendering (bands 4, 3, 2). Courtesy of Sentinel Hub Playground.

The average number of daily explosions during December 2019 decreased from a high of 16 the first week of the month to a low of five during the last week. Six pyroclastic flows occurred on 10 December (figure 78). Tremors were associated with gas-and-ash emissions for most of the month. Ashfall was reported in Pinchollo, Madrigal, Lari, Maca, Achoma, Coporaque, Yanque, and Chivay during the first week of the month, and in Huambo and Cabanaconde during the second week (figure 79). Inflation of the volcano was measured throughout the month. SO2 flux was measured by OVI as ranging from 2,500 to 4,300 tons per day.

Figure (see Caption) Figure 78. Multiple daily explosions at Sabancaya produced ash plumes that rose several kilometers above the summit. Left image is from 5 December and right image is from 11 December 2019. Note pyroclastic flows to the right of the crater on 11 December. Courtesy of OVI (Reporte Semanal de Monitorio de la Actividad de la Volcan Sabancaya, RSSAB-49-2019/INGEMMET Semana del 2 al 8 de diciembre de 2019 and RSSAB-50-2019/INGEMMET Semana del 9 al 15 de diciembre de 2019).
Figure (see Caption) Figure 79. Communities to the N and W of Sabancaya recorded ashfall from the volcano the first week of December and also every month during December 2019-May 2020. The red zone is the area where access is prohibited (about a 12-km radius from the crater). Courtesy of OVI (Reporte Semanal de Monitorio de la Actividad de la Volcan Sabancaya, RSSAB-22-2020/INGEMMET Semana del 25 al 31 de mayo del 2020).

During January and February 2020 the number of daily explosions averaged 4-20. Ash plumes rose as high as 3.4 km above the summit (figure 80) and drifted up to 30 km in multiple directions. Ashfall was reported in Chivay, Yanque, and Achoma on 8 January, and in Huambo on 25 February. Sulfur dioxide flux ranged from a low of 1,200 t/d on 29 February to a high of 8,200 t/d on 28 January. Inflation of the edifice was measured during January; deformation changed to deflation in early February but then returned to inflation by the end of the month.

Figure (see Caption) Figure 80. Ash plumes rose from Sabancaya every day during January and February 2020. Left: 11 January. Right: 28 February. Courtesy of OVI (Reporte Semanal de Monitorio de la Actividad de la Volcan Sabancaya, RSSAB-02-2020/INGEMMET Semana del 06 al 12 de enero del 2020 and RSSAB-09-2020/INGEMMET Semana del 24 de febrero al 01 de marzo del 2020).

Explosions continued during March and April 2020, averaging 8-29 per day. Explosions appeared to come from multiple vents on 11 March (figure 81). Ash plumes rose 3 km above the summit during the first week of March and again the first week of April; they were lower during the other weeks. Ashfall was reported in Madrigal, Lari, and Pinchollo on 27 March and 5 April. On 17 April ashfall was reported in Maca, Ichupampa, Yanque, Chivay, Coporaque, and Achoma. Sulfur dioxide flux ranged from 1,900 t/d on 5 March to 10,700 t/d on 30 March. Inflation at depth continued throughout March and April with 10 +/- 4 mm recorded between 21 and 26 April. Similar activity continued during May 2020; explosions averaged 6-16 per day (figure 82). Ashfall was reported on 6 May in Chivay, Achoma, Maca, Lari, Madrigal, and Pinchollo; heavy ashfall was reported in Achoma on 12 May. Additional ashfall was reported in Achoma, Maca, Madrigal, and Lari on 23 May.

Figure (see Caption) Figure 81. Explosions at Sabancaya on 11 March 2020 appeared to originate simultaneously from two different vents (left). The plume on 12 April was measured at about 2,500 m above the summit. Courtesy of OVI-INGEMMET (Reporte Semanal de Monitorio de la Actividad de la Volcan Sabancaya, RSSAB-11-2020/INGEMMET Semana del 9 al 15 de marzo del 2020 and RSSAB-15-2020/INGEMMET Semana del 6 al 12 de abril del 2020).
Figure (see Caption) Figure 82. Explosions dense with ash continued during May 2020 at Sabancaya. On 11 and 29 May 2020 ash plumes rose from the summit and drifted as far as 30 km before dissipating. Courtesy of OVI-INGEMMET (Reporte Semanal de Monitorio de la Actividad de la Volcan Sabancaya , RSSAB-20-2020/INGEMMET Semana del 11 al 17 de mayo del 2020 and RSSAB-22-2020/INGEMMET Semana del 25 al 31 de mayo del 2020).

Geologic Background. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of historical eruptions date back to 1750.

Information Contacts: Observatorio Volcanologico del INGEMMET (Instituto Geológical Minero y Metalúrgico), Barrio Magisterial Nro. 2 B-16 Umacollo - Yanahuara Arequipa, Peru (URL: http://ovi.ingemmet.gob.pe); Buenos Aires Volcanic Ash Advisory Center (VAAC), Servicio Meteorológico Nacional-Fuerza Aérea Argentina, 25 de mayo 658, Buenos Aires, Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/inicio.php); Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Sheveluch (Russia) — May 2020 Citation iconCite this Report

Sheveluch

Russia

56.653°N, 161.36°E; summit elev. 3283 m

All times are local (unless otherwise noted)


Lava dome growth and thermal anomalies continue through April 2020, but few ash explosions

The eruption at Sheveluch has continued for more than 20 years, with strong explosions that have produced ash plumes, lava dome growth, hot avalanches, numerous thermal anomalies, and strong fumarolic activity (BGVN 44:05). During this time, there have been periods of greater or lesser activity. The most recent period of increased activity began in December 2018 and continued through October 2019 (BGVN 44:11). This report covers activity between November 2019 to April 2020, a period during which activity waned. The volcano is monitored by the Kamchatka Volcanic Eruptions Response Team (KVERT) and Tokyo Volcanic Ash Advisory Center (VAAC).

During the reporting period, KVERT noted that lava dome growth continued, accompanied by incandescence of the dome blocks and hot avalanches. Strong fumarolic activity was also present (figure 53). However, the overall eruption intensity waned. Ash plumes sometimes rose to 10 km altitude and drifted downwind over 600 km (table 14). The Aviation Color Code (ACC) remained at Orange (the second highest level on a four-color scale), except for 3 November when it was raised briefly to Red (the highest level).

Figure (see Caption) Figure 53. Fumarolic activity of Sheveluch’s lava dome on 24 January 2020. Photo by Y. Demyanchuk; courtesy of KVERT.

Table 14. Explosions and ash plumes at Sheveluch during November 2019-April 2020. Dates and times are UTC, not local. Data courtesy of KVERT and the Tokyo VAAC.

Dates Plume Altitude (km) Drift Distance and Direction Remarks
01-08 Nov 2019 -- 640 km NW 3 November: ACC raised to Red from 0546-0718 UTC before returning to Orange.
08-15 Nov 2019 9-10 1,300 km ESE
17-27 Dec 2019 6.0-6.5 25 km E Explosions at about 23:50 UTC on 21 Dec.
20-27 Mar 2020 -- 45 km N 25 March: Gas-and-steam plume containing some ash.
03-10 Apr 2020 10 km 526 km SE 8 April: Strong explosion at 1910 UTC.
17-24 Apr 2020 -- 140 km NE Re-suspended ash plume.

KVERT reported thermal anomalies over the volcano every day, except for 25-26 January, when clouds obscured observations. During the reporting period, thermal anomalies, based on MODIS satellite instruments analyzed using the MODVOLC algorithm recorded hotspots on 10 days in November, 13 days in December, nine days in January, eight days in both February and March, and five days in April. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system, also based on analysis of MODIS data, detected numerous hotspots every month, almost all of which were of moderate radiative power (figure 54).

Figure (see Caption) Figure 54. Thermal anomalies at Sheveluch continued at elevated levels during November 2019-April 2020, as seen on this MIROVA Log Radiative Power graph for July 2019-April 2020. Courtesy of MIROVA.

High sulfur dioxide levels were occasionally recorded just above or in the close vicinity of Sheveluch by the TROPOspheric Monitoring Instrument (TROPOMI) aboard the Copernicus Sentinel-5 Precursor satellite, but very little drift was observed.

Geologic Background. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS), 9 Piip Blvd., Petropavlovsk-Kamchatsky 683006, Russia (URL: http://www.kscnet.ru/ivs/eng/); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/).


Dukono (Indonesia) — May 2020 Citation iconCite this Report

Dukono

Indonesia

1.693°N, 127.894°E; summit elev. 1229 m

All times are local (unless otherwise noted)


Numerous ash explosions continue through March 2020

The ongoing eruption at Dukono is characterized by frequent explosions that send ash plumes to about 1.5-3 km altitude (0.3-1.8 km above the summit), although a few have risen higher. This type of typical activity (figure 13) continued through at least March 2020. The ash plume data below (table 21) were primarily provided by the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) and the Darwin Volcanic Ash Advisory Centre (VAAC). During the reporting period of October 2019-March 2020, the Alert Level remained at 2 (on a scale of 1-4) and the public was warned to remain outside of the 2-km exclusion zone.

Table 21. Monthly summary of reported ash plumes from Dukono for October 2019-March 2020. The direction of drift for the ash plume through each month was highly variable; notable plume drift each month was only indicated in the table if at least two weekly reports were consistent. Data courtesy of the Darwin VAAC and PVMBG.

Month Plume Altitude (km) Notable Plume Drift
Oct 2019 1.8-3 Multiple
Nov 2019 1.8-2.3 E, SE, NE
Dec 2019 1.8-2.1 E, SE
Jan 2020 1.8-2.1 E, SE, SW, S
Feb 2020 2.1-2.4 S, SW
Mar 2020 1.5-2.3 Multiple
Figure (see Caption) Figure 13.Satellite image of Dukono from Sentinel-2 on 12 November 2019, showing an ash plume drifting E. Image uses natural color rendering (bands 4, 3, 2). Courtesy of Sentinel Hub Playground.

During the reporting period, high levels of sulfur dioxide were only recorded above or near the volcano during 30-31 October and 4 November 2019. High levels were recorded by the Ozone Mapping and Profiler Suite (OMPS) instrument aboard the Suomi National Polar-orbiting Partnership (NPP) satellite on 30 October 2019, in a plume drifting E. The next day high levels were also recorded by the TROPOspheric Monitoring Instrument (TROPOMI) aboard the Copernicus Sentinel-5 Precursor satellite on 31 October (figure 14) and 4 November 2019, in plumes drifting SE and NE, respectively.

Figure (see Caption) Figure 14. Sulfur dioxide emission on 31 October 2019 drifting E, probably from Dukono, as recorded by the TROPOMI instrument aboard the Sentinel-5P satellite. Courtesy of NASA Global Sulfur Dioxide Monitoring Page.

Geologic Background. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the north-flank cone of Gunung Mamuya. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Etna (Italy) — April 2020 Citation iconCite this Report

Etna

Italy

37.748°N, 14.999°E; summit elev. 3320 m

All times are local (unless otherwise noted)


Strombolian explosions and ash emissions continue, October 2019-March 2020

Mount Etna is a stratovolcano located on the island of Sicily, Italy, with historical eruptions that date back 3,500 years. The most recent eruptive period began in September 2013 and has continued through March 2020. Activity is characterized by Strombolian explosions, lava flows, and ash plumes that commonly occur from the summit area, including the Northeast Crater (NEC), the Voragine-Bocca Nuova (or Central) complex (VOR-BN), the Southeast Crater (SEC, formed in 1978), and the New Southeast Crater (NSEC, formed in 2011). The newest crater, referred to as the "cono della sella" (saddle cone), emerged during early 2017 in the area between SEC and NSEC. This reporting period covers information from October 2019 through March 2020 and includes frequent explosions and ash plumes. The primary source of information comes from the Osservatorio Etneo (OE), part of the Catania Branch of Italy's Istituo Nazionale di Geofisica e Vulcanologica (INGV).

Summary of activity during October 2019-March 2020. Strombolian activity and gas-and-steam and ash emissions were frequently observed at Etna throughout the entire reporting period, according to INGV and Toulouse VAAC notices. Activity was largely located within the main cone (Voragine-Bocca Nuova complex), the Northeast Crater (NEC), and the New Southeast Crater (NSEC). On 1, 17, and 19 October, ash plumes rose to a maximum altitude of 5 km. Due to constant Strombolian explosions, ground observations showed that a scoria cone located on the floor of the VOR Crater had begun to grow in late November and again in late January 2020. A lava flow was first detected on 6 December at the base of the scoria cone in the VOR Crater, which traveled toward the adjacent BN Crater. Additional lava flows were observed intermittently throughout the reporting period in the same crater. On 13 March, another small scoria cone had formed in the main VOR-BN complex due to Strombolian explosions.

MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data shows multiple episodes of thermal activity varying in power from 22 June 2019 to March 2020 (figure 286). The power and frequency of these thermal anomalies significantly decreased between August to mid-September. The pulse of activity in mid-September reflected a lava flow from the VOR Crater (BGVN 44:10). By late October through November, thermal anomalies were relatively weaker and less frequent. The next pulse in thermal activity reflected in the MIROVA graph occurred in early December, followed by another shortly after in early January, both of which were due to new lava flows from the VOR Crater. After 9 January the thermal anomalies remained frequent and strong; active lava flows continued through March accompanied by Strombolian explosions, gas-and-steam, SO2, and ash emissions. The most recent distinct pulse in thermal activity was seen in mid-March; on 13 March, another lava flow formed, accompanied by an increase in seismicity. This lava flow, like the previous ones, also originated in the VOR Crater and traveled W toward the BN Crater.

Figure (see Caption) Figure 286. Multiple episodes of varying activity at Etna from 22 June 2019 through March 2020 were reflected in the MIROVA thermal energy data (Log Radiative Power). Courtesy of MIROVA.

Activity during October-December 2019. During October 2019, VONA (Volcano Observatory Notice for Aviation) notices issued by INGV reported ash plumes rose to a maximum altitude of 5 km on 1, 17, and 19 October. Strombolian explosions occurred frequently. Explosions were detected primarily in the VOR-BN Craters, ejecting coarse pyroclastic material that fell back into the crater area and occasionally rising above the crater rim. Ash emissions rose from the VOR-BN and NEC while intense gas-and-steam emissions were observed in the NSEC (figure 287). Between 10-12 and 14-20 October fine ashfall was observed in Pedara, Mascalucia, Nicolosi, San Giovanni La Punta, and Catania. In addition to these ash emissions, the explosive Strombolian activity contributed to significant SO2 plumes that drifted in different directions (figure 288).

Figure (see Caption) Figure 287. Webcam images of ash emissions from the NE Crater at Etna from the a) CUAD (Catania) webcam on 10 October 2019; b) Milo webcam on 11 October 2019; c) Milo webcam on 12 October 2019; d) M.te Cagliato webcam on 13 October 2019. Courtesy of INGV (Report 42/2019, ETNA, Bollettino Settimanale, 07/10/2019 - 13/10/2019, data emissione 15/10/2019).
Figure (see Caption) Figure 288. Strombolian activity at Etna contributed to significant SO2 plumes that drifted in multiple directions during the intermittent explosions in October 2019. Top left: 1 October 2019. Top right: 2 October 2019. Middle left: 15 October 2019. Middle right: 18 October 2019. Bottom left: 13 November 2019. Bottom right: 1 December 2019. Captured by the TROPOMI instrument on the Sentinel 5P satellite, courtesy of NASA Global Sulfur Dioxide Monitoring Page.

The INGV weekly bulletin covering activity between 25 October and 1 November 2019 reported that Strombolian explosions occurred at intervals of 5-10 minutes from within the VOR-BN and NEC, ejecting incandescent material above the crater rim, accompanied by modest ash emissions. In addition, gas-and-steam emissions were observed from all the summit craters. Field observations showed the cone in the crater floor of VOR that began to grow in mid-September 2019 had continued to grow throughout the month. During the week of 4-10 November, Strombolian activity within the Bocca Nuova Crater was accompanied by gas-and-steam emissions. The explosions in the VOR Crater occasionally ejected incandescent ejecta above the crater rim (figures 289 and 290). For the remainder of the month Strombolian explosions continued in the VOR-BN and NEC, producing sporadic ash emissions. Isolated and discontinuous explosions in the New Southeast Crater (NSEC) also produced fine ash, though gas-and-steam emissions still dominated the activity at this crater. Additionally, the explosions from these summit craters were frequently accompanied by strong SO2 emissions that drifted in different directions as discrete plumes.

Figure (see Caption) Figure 289. Photo of Strombolian activity and crater incandescence in the Voragine Crater at Etna on 15 November 2019. Photo by B. Behncke, taken by Tremestieri Etneo. Courtesy of INGV (Report 47/2019, ETNA, Bollettino Settimanale, 11/11/2019 - 17/11/2019, data emissione 19/11/2019).
Figure (see Caption) Figure 290. Webcam images of summit crater activity during 26-29 November and 1 December 2019 at Etna. a) image recorded by the high-resolution camera on Montagnola (EMOV); b) and c) webcam images taken from Tremestieri Etneo on the southern slope of Etna showing summit incandescence; d) image recorded by the thermal camera on Montagnola (EMOT) showing summit incandescence at the NSEC. Courtesy of INGV (Report 49/2019, ETNA, Bollettino Settimanale, 25/11/2019 - 01/12/2019, data emissione 03/12/2019).

Frequent Strombolian explosions continued through December 2019 within the VOR-BN, NEC, and NSEC Craters with sporadic ash emissions observed in the VOR-BN and NEC. On 6 December, Strombolian explosions increased in the NSEC; webcam images showed incandescent pyroclastic material ejected above the crater rim. On the morning of 6 December a lava flow was observed from the base of the scoria cone in the VOR Crater that traveled toward the adjacent Bocca Nuova Crater. INGV reported that a new vent opened on the side of the saddle cone (NSEC) on 11 December and produced explosions until 14 December.

Activity during January-March 2020. On 9 January 2020 an aerial flight organized by RAI Linea Bianca and the state police showed the VOR Crater continuing to produce lava that was flowing over the crater rim into the BN Crater with some explosive activity in the scoria cone. Explosive Strombolian activity produced strong and distinct SO2 plumes (figure 291) and ash emissions through March, according to the weekly INGV reports, VONA notices, and satellite imagery. Several ash emissions during 21-22 January rose from the vent that opened on 11 December. According to INGV’s weekly bulletin for 21-26 January, the scoria cone in the VOR crater produced Strombolian explosions that increased in frequency and contributed to rapid cone growth, particularly the N part of the cone. Lava traveled down the S flank of the cone and into the adjacent Bocca Nuova Crater, filling the E crater (BN-2) (figure 292). The NEC had discontinuous Strombolian activity and periodic, diffuse ash emissions.

Figure (see Caption) Figure 291. Distinct SO2 plumes drifting in multiple directions from Etna were visible in satellite imagery as Strombolian activity continued through March 2020. Top left: 21 January 2020. Top right: 2 February 2020. Bottom left: 10 March 2020. Bottom right: 19 March 2020. Captured by the TROPOMI instrument on the Sentinel 5P satellite, courtesy of NASA Global Sulfur Dioxide Monitoring Page.
Figure (see Caption) Figure 292. a) A map of the lava field at Etna showing cooled flows (yellow) and active flows (red). The base of the scoria cone is outlined in black while the crater rim is outlined in red. b) Thermal image of the Bocca Nuova and Voragine Craters. The bright orange is the warmest temperature measure in the flow. Courtesy of INGV, photos by Laboratorio di Cartografia FlyeEye Team (Report 10/2020, ETNA, Bollettino Settimanale, 24/02/2020 - 01/03/2020, data emissione 03/03/2020).

Strombolian explosions continued into February 2020, accompanied by ash emissions and lava flows from the previous months (figure 293). During 17-23 February, INGV reported that some subsidence was observed in the central portion of the Bocca Nuova Crater. During 24 February to 1 March, the Strombolian explosions ejected lava from the VOR Crater up to 150-200 m above the vent as bombs fell on the W edge of the VOR crater rim (figure 294). Lava flows continued to move into the W part of the Bocca Nuova Crater.

Figure (see Caption) Figure 293. Webcam images of A) Strombolian activity and B) effusive activity fed by the scoria cone grown inside the VOR Crater at Etna taken on 1 February 2020. C) Thermal image of the lava field produced by the VOR Crater taken by L. Lodato on 3 February (bottom left). Image of BN-1 taken by F. Ciancitto on 3 February in the summit area (bottom right). Courtesy of INGV; Report 06/2020, ETNA, Bollettino Settimanale, 27/01/2020 - 02/02/2020, data emissione 04/02/2020 (top) and Report 07/2020, ETNA, Bollettino Settimanale, 03/02/2020 - 09/02/2020, data emissione 11/02/2020 (bottom).
Figure (see Caption) Figure 294. Photos of the VOR intra-crater scoria cone at Etna: a) Strombolian activity resumed on 25 February 2020 from the SW edge of BN taken by B. Behncke; b) weak Strombolian activity from the vent at the base N of the cone on 29 February 2020 from the W edge of VOR taken by V. Greco; c) old vent present at the base N of the cone, taken on 17 February 2020 from the E edge of VOR taken by B. Behncke; d) view of the flank of the cone, taken on 24 February 2020 from the W edge of VOR taken by F. Ciancitto. Courtesy of INGV (Report 10/2020, ETNA, Bollettino Settimanale, 24/02/2020 - 01/03/2020, data emissione 03/03/2020).

During 9-15 March 2020 Strombolian activity was detected in the VOR Crater while discontinuous ash emissions rose from the NEC and NSEC. Bombs were found in the N saddle between the VOR and NSEC craters. On 9 March, a small scoria cone that had formed in the Bocca Nuova Crater and was ejecting bombs and lava tens of meters above the S crater rim. The lava flow from the VOR Crater was no longer advancing. A third scoria cone had formed on 13 March NE in the main VOR-BN complex due to the Strombolian explosions on 29 February. Another lava flow formed on 13 March, accompanied by an increase in seismicity. The weekly report for 16-22 March reported Strombolian activity detected in the VOR Crater and gas-and-steam and rare ash emissions observed in the NEC and NSEC (figure 295). Explosions in the Bocca Nuova Crater ejected spatter and bombs 100 m high.

Figure (see Caption) Figure 295. Map of the summit crater area of Etna showing the active vents and lava flows during 16-22 March 2020. Black hatch marks indicate the crater rims: BN = Bocca Nuova, with NW BN-1 and SE BN-2; VOR = Voragine; NEC = North East Crater; SEC = South East Crater; NSEC = New South East Crater. Red circles indicate areas with ash emissions and/or Strombolian activity, yellow circles indicate steam and/or gas emissions only. The base is modified from a 2014 DEM created by Laboratorio di Aerogeofisica-Sezione Roma 2. Courtesy of INGV (Report 13/2020, ETNA, Bollettino Settimanale, 16/03/2020 - 22/03/2020, data emissione 24/03/2020).

Geologic Background. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.

Information Contacts: Sezione di Catania - Osservatorio Etneo, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania, Piazza Roma 2, 95123 Catania, Italy (URL: http://www.ct.ingv.it/it/); Toulouse Volcanic Ash Advisory Center (VAAC), Météo-France, 42 Avenue Gaspard Coriolis, F-31057 Toulouse cedex, France (URL: http://www.meteo.fr/aeroweb/info/vaac/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); Boris Behncke, Sonia Calvari, and Marco Neri, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania, Piazza Roma 2, 95123 Catania, Italy (URL: https://twitter.com/etnaboris, Image at https://twitter.com/etnaboris/status/1183640328760414209/photo/1).


Merapi (Indonesia) — April 2020 Citation iconCite this Report

Merapi

Indonesia

7.54°S, 110.446°E; summit elev. 2910 m

All times are local (unless otherwise noted)


Explosions produced ash plumes, ashfall, and pyroclastic flows during October 2019-March 2020

Merapi is a highly active stratovolcano located in Indonesia, just north of the city of Yogyakarta. The current eruption episode began in May 2018 and was characterized by phreatic explosions, ash plumes, block avalanches, and a newly active lava dome at the summit. This reporting period updates information from October 2019-March 2020 that includes explosions, pyroclastic flows, ash plumes, and ashfall. The primary reporting source of activity comes from Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG, the Center for Research and Development of Geological Disaster Technology, a branch of PVMBG) and Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM).

Some ongoing lava dome growth continued in October 2019 in the NE-SW direction measuring 100 m in length, 30 m in width, and 20 m in depth. Gas-and-steam emissions were frequent, reaching a maximum height of 700 m above the crater on 31 October. An explosion at 1631 on 14 October removed the NE-SW trending section of the lava dome and produced an ash plume that rose 3 km above the crater and extended SW for about 2 km (figures 90 and 91). The plume resulted in ashfall as far as 25 km to the SW. According to a Darwin VAAC notice, a thermal hotspot was detected in HIMAWARI-8 satellite imagery. A pyroclastic flow associated with the eruption traveled down the SW flank in the Gendol drainage. During 14-20 October lava flows from the crater generated block-and-ash flows that traveled 1 km SW, according to BPPTKG.

Figure (see Caption) Figure 90. An ash plume rising 3 km above Merapi on 14 October 2019.
Figure (see Caption) Figure 91. Webcam image of an ash plume rising above Merapi at 1733 on 14 October 2019. Courtesy of BPPTKG via Jaime S. Sincioco.

At 0621 on 9 November 2019, an eruption produced an ash plume that rose 1.5 km above the crater and drifted W. Ashfall was observed in the W region as far as 15 km from the summit in Wonolelo and Sawangan in Magelang Regency, as well as Tlogolele and Selo in Boyolali Regency. An associated pyroclastic flow traveled 2 km down the Gendol drainage on the SE flank. On 12 November aerial drone photographs were used to measure the volume of the lava dome, which was 407,000 m3. On 17 November, an eruption produced an ash plume that rose 1 km above the crater, resulting in ashfall as far as 15 km W from the summit in the Dukun District, Magelang Regency (figure 92). A pyroclastic flow accompanying the eruption traveled 1 km down the SE flank in the Gendol drainage. By 30 November low-frequency earthquakes and CO2 gas emissions had increased.

Figure (see Caption) Figure 92. An ash plume rising 1 km above Merapi on 17 November 2019. Courtesy of BPPTKG.

Volcanism was relatively low from 18 November 2019 through 12 February 2020, characterized primarily by gas-and-steam emissions and intermittent volcanic earthquakes. On 4 January a pyroclastic flow was recorded by the seismic network at 2036, but it wasn’t observed due to weather conditions. On 13 February an explosion was detected at 0516, which ejected incandescent material within a 1-km radius from the summit (figure 93). Ash plumes rose 2 km above the crater and drifted NW, resulting in ashfall within 10 km, primarily S of the summit; lightning was also seen in the plume. Ash was observed in Hargobinangun, Glagaharjo, and Kepuharjo. On 19 February aerial drone photographs were used to measure the change in the lava dome after the eruption; the volume of the lava had decreased, measuring 291,000 m3.

Figure (see Caption) Figure 93. Webcam image of an ash plume rising from Merapi at 0516 on 13 February 2020. Courtesy of MAGMA Indonesia and PVMBG.

An explosion on 3 March at 0522 produced an ash plume that rose 6 km above the crater (figure 94), resulting in ashfall within 10 km of the summit, primarily to the NE in the Musuk and Cepogo Boyolali sub-districts and Mriyan Village, Boyolali (3 km from the summit). A pyroclastic flow accompanied this eruption, traveling down the SSE flank less than 2 km. Explosions continued to be detected on 25 and 27-28 March, resulting in ash plumes. The eruption on 27 March at 0530 produced an ash plume that rose 5 km above the crater, causing ashfall as far as 20 km to the W in the Mungkid subdistrict, Magelang Regency, and Banyubiru Village, Dukun District, Magelang Regency. An associated pyroclastic flow descended the SSE flank, traveling as far as 2 km. The ash plume from the 28 March eruption rose 2 km above the crater, causing ashfall within 5 km from the summit in the Krinjing subdistrict primarily to the W (figure 94).

Figure (see Caption) Figure 94. Images of ash plumes rising from Merapi during 3 March (left) and 28 March 2020 (right). Images courtesy of BPPTKG (left) and PVMBG (right).

Geologic Background. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities during historical time.

Information Contacts: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG), Center for Research and Development of Geological Disaster Technology (URL: http://merapi.bgl.esdm.go.id/, Twitter: @BPPTKG); Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Badan Nasional Penanggulangan Bencana (BNPB), National Disaster Management Agency, Graha BNPB - Jl. Scout Kav.38, East Jakarta 13120, Indonesia (URL: http://www.bnpb.go.id/, Twitter: https://twitter.com/BNPB_Indonesia); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Jamie S. Sincioco, Phillipines (Twitter: @jaimessincioco, Image at https://twitter.com/jaimessincioco/status/1227966075519635456/photo/1).

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Bulletin of the Global Volcanism Network - Volume 29, Number 02 (February 2004)

Managing Editor: Edward Venzke

Erta Ale (Ethiopia)

February 2004 expedition finds molten-surfaced lava lake nearly gone

Kilauea (United States)

Activity through April 2004 focuses in upper flow field (maps and diagrams)

Langila (Papua New Guinea)

MODIS thermal alerts in April 2003, and January 2004

Lengai, Ol Doinyo (Tanzania)

During February 2004, lavas still escape crater; temperature measurements

Llaima (Chile)

Extreme glacial crevassing and melting; April 2003 ash emissions

Manam (Papua New Guinea)

One minor eruption but otherwise low activity during February 2004

Rabaul (Papua New Guinea)

1-17 February 2004-ash falls 30 km to the E

Ruang (Indonesia)

Eruption on 25 September 2002 is the largest in Indonesia in many years

Ruapehu (New Zealand)

Strategy, prediction, and management of crater-lake overflow and powerful lahar

Soufriere Hills (United Kingdom)

Ash to 7 km altitude on 3 March 2004; pyroclastic flows reached the sea

Stromboli (Italy)

After 10 February 2004, explosions at upper limit of that typically seen

Ulawun (Papua New Guinea)

Tabulation of aviation reports issued during 2000-mid-2003

Witori (Papua New Guinea)

Two explosions on 24 February 2004, otherwise quiet during that month



Erta Ale (Ethiopia) — February 2004 Citation iconCite this Report

Erta Ale

Ethiopia

13.6°N, 40.67°E; summit elev. 613 m

All times are local (unless otherwise noted)


February 2004 expedition finds molten-surfaced lava lake nearly gone

In February 2004 an expedition led by German scientists visited Erta Ale. Afterwards, an overflight completed the survey of volcanic activity. Of significance was the discovery that an earlier lava lake had largely disappeared. Information from their report follows.

German scientists were at Erta Ale during 9-13 February 2004. They explored areas around the S crater of the volcano, which for the past several years has contained an active lava lake (see BGVN 28:04 and 26:12). The S crater retained only a very small fraction of the former lava lake. When visited it stood ~ 15 m in diameter, located roughly in the center of the old lake. Around the small lake were many active gas vents, and there was a hornito, about 2 m tall, on the SE side. Behind its ~ 1.5-m-high walls, the lake's lava changed levels and occasional lava fountains rose to ~ 10 m high.

On 12 February the expedition team descended to the second terrace (~90 m below the rim) of the S crater, to the surface of the former lake, and approached the small elevated lake. Samples of newly ejected lava were collected, and some were given to Gezahegn Yirgu at the University of Addis Ababa for analysis. Samples retained by the expedition team showed white crystals, approximately 1-2 mm in size, embedded in black material. On the evening of 12 February the team witnessed an overflow of the little lake, flooding the NW half of the second terrace. Parts of the western lake wall eventually collapsed, causing a lava flood wave as well as more violent fountaining (up to 20 m). This event lasted approximately 2 hours.

The entire crater was fogged by fumaroles, which were mainly active in the SE corner of the first terrace (~ 50 m below the rim). Gas masks were necessary inside the crater. From the smell and (blueish) color, these gases contained a high quantity of SO2.

No earthquakes were felt during the visit.

On 21 February a low overflight was made across the volcano. There were no more signs of a lava lake, and only three hornitos were active. Although the flight was made during the day, the glow allowed the hornitos to be visible. Upon return, Chris Heinlein noted that he found photos on the web by Luigi Cantamessa showing that during 15-17 November 2003 the lava lake was also largely gone.

Geologic Background. Erta Ale is an isolated basaltic shield that is the most active volcano in Ethiopia. The broad, 50-km-wide edifice rises more than 600 m from below sea level in the barren Danakil depression. Erta Ale is the namesake and most prominent feature of the Erta Ale Range. The volcano contains a 0.7 x 1.6 km, elliptical summit crater housing steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located SE of the summit and is bounded by curvilinear fault scarps on the SE side. Fresh-looking basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera is renowned for one, or sometimes two long-term lava lakes that have been active since at least 1967, or possibly since 1906. Recent fissure eruptions have occurred on the N flank.

Information Contacts: Carsten Peter, Meilenbergerstr. 1, D-82057 Icking-Dorfen, Germany; Chris Heinlein, Kreuzelbergstr. 62, 76189 Karlsruhe, Germany; Arne Kaiser, Institute of Geophysics, University of Hamburg, Bundesstraβe 55, 20146 Hamburg, Germany; Luigi Cantamessa, Geó-Découverte, 12-14 rue de Cendrier, CH-1201 Geneva, Switzerland (URL: http://geo-decouverte.ch/); Gezahegn Yirgu, Department of Geology and Geophysics, Faculty of Science, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia (URL: http://www.aau.edu.et/natural-sciences/geology/).


Kilauea (United States) — February 2004 Citation iconCite this Report

Kilauea

United States

19.421°N, 155.287°W; summit elev. 1222 m

All times are local (unless otherwise noted)


Activity through April 2004 focuses in upper flow field (maps and diagrams)

Kilauea continued to be active at Pu`u `O`o during December 2003 through early March 2004. Figure 161 shows simplified maps and a diagrammatic cross-section on the Island of Hawaii, emphasizing local geography, and known and inferred conditions at Kilauea. During the reporting interval observers noted incandescence and surface lava flows at Kilauea's upper flow field. In general, surface lava flows were not seen on the coastal flat or Pulama pali. Various vents within Pu`u `O`o were active, and new lava flows covered parts of the crater floor. Seismicity at Kilauea has generally included a few small earthquakes recorded at the volcano's summit, along with steady weak tremor. Tremor occurred continuously at moderate levels at Pu`u `O`o.

Figure (see Caption) Figure 161. A map and cross-sectional diagram illustrating the island of Hawaii (the 'Big Island,' the largest and southernmost in the Hawaiian chain) showing selected volcanological features and some local geography. The inset shows how the island of Hawaii consists of five volcanoes (old to young): Kohala, Hualalai, Mauna Kea, Mauna Loa, and Kilauea. The larger map emphasizes Kilauea's features. Kilauea is cut by two rift zones, the SW and E rift zones. The east rift zone extends 55 km from the summit caldera to the eastern tip of the Island of Hawaii. The E rift zone contains a string of craters, including Pu`u `O`o. The cross-sectional diagram displays a simplified model of Kilauea's internal structure. Note the location of vents, at Pu`u `O`o and elsewhere, along the SW rift zone. The diagram also shows a lava tube running from Pu`u `O`o to the sea. The map and diagram both omit the details of recent eruptive events; for that, see later figures. Courtesy of the Hawaiian Volcano Observatory, U.S. Geological Survey.

During 0550 to 0830 on 18 January 2004, a large period of tilt occurred at Kilauea's Pu`u `O`o cone, amounting to 18.1 microradians of net deflation. During this period a fissure opened at the SE base of Pu`u `O`o, trending approximately radial to the cone. Lava was emitted from the fissure and from three to four vents nearby. The initial flow reached about 1.5 km S of the cone. The S side of Pu`u `O`o was cut by many new fractures. The longest fracture constituted the N boundary of a shallow graben (a linear trough bounded by faults) that was ~ 75 m long and up to 1 m deep. Surface lava flows were emitted from the E end of the graben, at the base of Pu`u `O`o. The area S of Pu`u `O`o cone appeared to be quite unstable, so Hawaiian Volcano Observatory (HVO) scientists warned that no one should venture into the area. Seismicity at Kilauea's summit during 15-20 January was at low levels, while tremor at Pu`u `O`o was continuous and at moderate levels. The tremor picked up during the formation of the graben on 18 January. As of 20 January tilt continued to steadily decline following the 18 January deflation event.

On 22 January lava was emitted from the vent formed on 19 January. The vent and lava flow S of Pu`u `O`o cone were named MLK in honor of the activity that began on the American civil rights leader M.L. King Jr.'s birthday (19 January; see figures 162 and 163).

Figure (see Caption) Figure 162. A sketch map showing Kilauea's lava flows erupted during 1983-23 January 2004 activity of Pu`u `O`o and Kupaianaha. Lava flows began erupting from new MLK vent at the base of Pu`u `O`o (star) on 18 January 2004. Stars indicate centers of recently active, or still active, rootless shields in Mother's Day flow. New shields form often and not all shields appear on this map. Courtesy of the Hawaiian Volcano Observatory, U.S. Geological Survey.
Figure (see Caption) Figure 163. Sketch map of Pu`u `O`o region through 26 January 2004 identifying numerous vents, groups of lava flows, and other features referred to in this and previous issues of the Bulletin. Note the names assigned to intra-crater vents in the oval-shaped interior of Pu`u `O`o cone (stars 1-7) and the various rootless shields farther to the W. Courtesy of Hawaii Volcano Observatory, U. S. Geological Survey.

A term that has come into common use at Kilauea is "rootless shield." Local geologists define this as a pile of lava flows built over a lava tube rather than over a conduit feeding magma from within the Earth. Rootless shields along the tube system commonly have flat tops containing shallow lava ponds. In the reporting interval, there were also surface lava flows at the W side of the rootless shield called Amalgamated Bend, a feature located SW of Pu`u `O`o (figure 6). By 26 January there were no surface lava flows at the MLK vent, and incandescence was only visible at the S part of the rootless shield complex. On 23 January moderate-to-strong tremor stopped beneath Kilauea's caldera and lessened at Pu`u `O`o. On 26 January deflation that began on 18 January ended at Pu`u `O`o after reaching 24.7 microradians. This was probably the largest deflation event since early 1997.

During 29 January to 1 February mild volcanic activity occurred at Kilauea, with incandescence visible at vents in Pu`u `O`o's crater and small surface flows on the central or southern part of the rootless shield complex. Starting on 18 January, when the MLK vent formed, the distance across the summit caldera decreased significantly, ending a period of increasing extension rate since the Mother's Day event in May 2002. During the report period, weak tremor occurred at Kilauea's summit along with a few long-period earthquakes. Tremor at Pu`u `O`o remained moderate. During much of February 2004 and into early March, lava flows and incandescence were sometimes visible in Pu`u `O`o's crater and at the rootless shield complex (an area ~ 0.5 km SW of Pu`u `O`o). Weak background tremor occurred at Kilauea's summit along with a few long-period earthquakes. Tremor at Pu`u `O`o was at moderate-to-low levels. Small deflation and inflation events occurred at the summit and at Pu`u `O`o.

Geologic Background. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 km2, destroying nearly 200 houses and adding new coastline to the island.

Information Contacts: Hawaiian Volcano Observatory (HVO), U.S. Geological Survey, PO Box 51, Hawaii National Park, HI 96718, USA (URL: https://volcanoes.usgs.gov/observatories/hvo/).


Langila (Papua New Guinea) — February 2004 Citation iconCite this Report

Langila

Papua New Guinea

5.525°S, 148.42°E; summit elev. 1330 m

All times are local (unless otherwise noted)


MODIS thermal alerts in April 2003, and January 2004

Langila was last reported in BGVN 28:03, following a large ash-bearing explosion on 18 January 2003. MODIS thermal alerts were subsequently recorded on 9 April and 20, 23, 25, and 27 January 2004. One daylight alert was received and omitted (22 September 2003). Daylight alerts posted by the current algorithm are considered less reliable. No corroborative reports of activity have been received from the Rabaul Volcano Observatory or the Darwin Volcanic Ash Advisory Center (VAAC).

Geologic Background. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower eastern flank of the extinct Talawe volcano. Talawe is the highest volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila volcano was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the north and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit of Langila. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m.

Information Contacts: Rob Wright, Luke Flynn, and Eric Pilger, MODIS Thermal Alert System, Hawaii Institute of Geophysics and Planetology (HIGP), School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (URL: http://modis.hgip.hawaii.edu/).


Ol Doinyo Lengai (Tanzania) — February 2004 Citation iconCite this Report

Ol Doinyo Lengai

Tanzania

2.764°S, 35.914°E; summit elev. 2962 m

All times are local (unless otherwise noted)


During February 2004, lavas still escape crater; temperature measurements

Activity at Ol Doinyo Lengai has continued intermittently since October 2002 (BGVN 27:10). (According to Fred Belton, in that same month, October 2002, Paramount Pictures used the crater to shoot footage for the film "Tomb Raiders II.").

This summary report for 2003 is based on observations made by Joerg Keller, Jurgis Klaudius, Fred Belton, and Christoph Weber, as well as information collected by Celia Nyamweru from visits to the area. Christoph Weber most recently visited Lengai in February 2004, when he collected GPS data for a new, precise crater map (figure 78). He also took temperature measurements of fumaroles and lava flows (see tables 5 and 6), and gathered lava samples to be given to research departments.

Figure (see Caption) Figure 78. GPS-aided sketch map of the crater at Ol Doinyo Lengai made on 14 February 2004. Note the lava flow paths over the crater's margin on onto the flanks ("overflows") that have started in the past several years. Subsequent figures (photos) help clarify the shapes and sizes of hornitos and other features. Naming conventions are complicated by the crater's rapidly changing landscape, including such processes at hornitos as collapse, clustering, and overlap. For example, hornito T48, which was described as having collapsed in July 2000, lies on the N margin of the hornito labeled as T58B. The lava ponds seen by Hloben in January 2001 are not shown, although some of their locations may coincide with later features. For detailed comparison of crater evolution and naming conventions, consult previous maps (eg., BGVN 27:10). Courtesy of Christoph Weber, Volcano Expeditions International and Volcano Hazards Documentation and Logistic Research.

Table 5. Lava temperature measured at Ol Doinyo Lengai by a digital thermometer (TM 914C with a stab feeler, standard K-Type). The instrument was used in the 0-1200° Celsius mode. Calibration was made using the delta-T method, where temperature values are +/- 6°C in the 0-750°C range associated with at least four replicate measurements at one spot. Courtesy of Christoph Weber.

Date Location Temperature (°C)
28 Aug 1999 T40 lava lake 529
01 Sep 1999 Pahoehoe flow in a tube near T40 519
01 Sep 1999 Aa flow still in motion on flat terrain (60 cm thick) 516
03 Oct 2000 Pahoehoe flow in a tube near T49B 507
03 Oct 2000 Aa flow still in slow motion on flat terrain (25 cm thick) 496
11 Feb 2004 Pahoehoe flow in a tube near T49G 588
12 Feb 2004 Pahoehoe flow in a tube near T49B 579
13 Feb 2004 Aa flow immobile and on flat terrain (15 cm thick) 490

Table 6. Fumarole temperatures measured at cracks in the crater floor of Ol Doinyo Lengai, using the above-described digital thermometer. Courtesy of Christoph Weber.

Date Location Temperature (°C)
28 Aug 1999 F1 70
28 Aug 1999 Near T49 82
03 Oct 2000 Near T49C 75
03 Oct 2000 F1 69
20 Oct 2002 The hottest cracks in the crater floor 124
20 Oct 2002 F1 78
30 Jun 2003 F1 86
30 Jun 2003 Near T49C 76
12 Feb 2004 F1 88

Summary of 2003 activity. During the first half of 2003, two new hornitos appeared in the center of the active crater at Ol Doinyo Lengai at the T49 and T58B (T48) locations (see figure 78 and caption). A huge lava pond appeared at these locations and caused several lava flows in all directions. According to Burra Gadiye, a local Lengai observer, by mid-June unusually dramatic activity started at both new hornitos. An expedition led by Frederick Belton in August 2003 reported that strong degassing and rhythmic explosive eruptions threw lapilli, ash, and lava spatter to 100 m above the hornito. Those eruptions, best described as Strombolian, continued until January 2004. They were accompanied by several lava flows and built up the comparatively tall strato-type hornitos at the T49-T56B locations and at the T48-T48B-T58B locations. The summit of T48B stood just above the former T44 hornito, but T44 itself was no longer visible.

Observations during February 2004. An expedition team including Christoph Weber and others visited Lengai for five days, 10-14 February 2004 (figures 79, 80, and 81). The team used GPS to conclude that the summit of the tallest hornito, located in the center area of the active crater at Ol Doinyo Lengai (T49 or T56B location), was at approximately 2,886 m elevation, standing about 33 m above the surrounding crater floor to the N. While this hornito was no longer active, T48B (T58B) contained a lava lake deep inside, which was clearly indicated by noise and tremor. Observers in February noted effusive and lava lake activity. This occurred at the old T49 eruption center, also indicated by the activity of T49B during observation and an active new vent (numbered T49G by Weber, figure 81) at the N flank of T49 (T56B), about half way up from its base to the N side.

Figure (see Caption) Figure 79. Ol Doinyo Lengai as seen in February 2004 from its summit, looking towards the actively erupting N crater. Courtesy Christoph Weber.
Figure (see Caption) Figure 80. View of the tallest hornito (T56B) at Ol Doinyo Lengai in February 2004. T56B sits in the center of the active (N) crater. The hornito's summit was at 2,886 m elevation. Lava flows are visible in the foreground. Courtesy Christoph Weber.
Figure (see Caption) Figure 81. View of Ol Doinyo Lengai looking towards the W, facing the lava lake at T49G and the active peak at T49B. Courtesy Christoph Weber.

This new activity probably caused two collapses (which left depressions) in the N flank of T49 (T56B), seen since January 2004. The T49G vent, located at the upper collapse, had a steady degassing lava lake with many overflows recorded during the February visit. Lava penetrated the lower collapse at T49 and lava flows reached as far as the NW overflow. On 12 and 13 February the T49B vent spattered lava for hours, feeding lava flows to the W (to the vicinity of T51), and finally escaping into a lava tube system. The lava temperature very close to the lava lake was measured at 588°C. Immobile aa lava flows on flat terrain were measured between 480°C and 500°C (table 5).

On 7 February team members Christoph Weber and R. Albiez were staying at the N slope of the neighboring Karimassi volcano and heard a paroxysm at T48B (T58B) lasting 30 seconds. During the visit on 10 February evidence of this paroxysm included fresh lava spatter and bombs cast around T58B for a radius of ~ 100 m.

Evacuation project at Ol Doinyo Lengai. Contributors to this report belong to a group committed to creating and funding evacuation plans. That group is called Volcano Hazards Documentation and Logistic Research (see Information Contacts). The group is working with the local Masaii and authorities on preparations in case of a dangerous eruption.

Geologic Background. The symmetrical Ol Doinyo Lengai is the only volcano known to have erupted carbonatite tephras and lavas in historical time. The prominent stratovolcano, known to the Maasai as "The Mountain of God," rises abruptly above the broad plain south of Lake Natron in the Gregory Rift Valley. The cone-building stage ended about 15,000 years ago and was followed by periodic ejection of natrocarbonatitic and nephelinite tephra during the Holocene. Historical eruptions have consisted of smaller tephra ejections and emission of numerous natrocarbonatitic lava flows on the floor of the summit crater and occasionally down the upper flanks. The depth and morphology of the northern crater have changed dramatically during the course of historical eruptions, ranging from steep crater walls about 200 m deep in the mid-20th century to shallow platforms mostly filling the crater. Long-term lava effusion in the summit crater beginning in 1983 had by the turn of the century mostly filled the northern crater; by late 1998 lava had begun overflowing the crater rim.

Information Contacts: Christoph Weber, Volcano Expeditions International, Muehlweg 11, 74199 Untergruppenbach, Germany (URL: http://www.v-e-i.de); Celia Nyamweru, Department of Anthropology, St. Lawrence University, Canton NY 13617 USA (URL: http://blogs.stlawu.edu/lengai/); Jurgis Klaudius, IMPG, Albert-Ludwig-University Freiburg, Albertstrasse 23b, 79104 Freiburg, Germany; Frederick Belton, 3555 Philsdale Ave., Memphis, TN 38111 USA (URL: http://oldoinyolengai.pbworks.com/); Volcano Hazards Documentation and Logistic Research, VHDL; Germany, Muehlweg 11, 74199 Untergruppenbach (URL: http://www.v-e-i.de/vhdl/).


Llaima (Chile) — February 2004 Citation iconCite this Report

Llaima

Chile

38.692°S, 71.729°W; summit elev. 3125 m

All times are local (unless otherwise noted)


Extreme glacial crevassing and melting; April 2003 ash emissions

During late 2002 and early 2003 Chilean scientists at Llaima documented increases in seismicity, fumarolic output, a minor eruption, and pronounced glacial disruption. For example, on 8 January 2003 they found that the ice and snow formerly capping the N and S craters had completely melted. Larger eruptions began in April 2003, depositing pyroclastic material, dispersing numerous ballistic blocks, and creating substantial plumes.

Although this report covers the time interval from January 2002 through most of April 2003, the concern then was that Llaima might erupt with the vigor seen in 1994 (BGVN 19:04 and 19:05). However, during the 2002-03 reporting interval eruptions remained comparatively modest.

Ice covered, passively degassing. On 26 September and 30 October 2002, scientists from Chile's Volcanic Risk Program and the Volcanologic Observatory of the South Andes (OVDAS) flew over Llaima in response to steady increases in seismicity and fumarolic activity since the end of June 2002. On the 26 September flight they viewed the summit with its N (main) crater, and Pichillaima, the smaller SE-flank cone and its crater. They found only a weak steam plume rising gently from the main crater and attaining little additional height. This was in contrast to typical previous behavior, which consisted of puffs that rose several hundred meters before dissipating.

The 26 September 2002 aerial observations found the internal walls of the main crater draped in ice and snow. Pichillaima lay beneath a cover of clean ice and snow, and its crater emitted only a small gas plume. The overall scene was of quiet, with minor degassing amid frigid conditions.

Views of the main crater rim on 30 October 2002 indicated minor ash on the snow, an irregular, figure-eight-shaped hole emitting gases, and a much larger and optically denser steam plume than on 26 September. Llaima's cover of ice and snow was more complete than noted in October 1998. Thus, by comparison, in late 2002 visible signs of thermal activity had diminished significantly. In contrast to what was typically seen, the crater's ice-covered internal walls lacked escaping gases. Except for seismicity, the ice-bound Llaima seemed stable.

Seismically restless. Despite the lack of visible volcanism or thermal activity, the seismicity in September 2002 was notably greater than in January 2002 (table 2). The frequency of tremor increased from 0.9 Hz in January 2002 (a typical value in times of relative quiet) to 1.2 Hz in September 2002. In describing April 2003 tremor amplitude the OVDAS reports stated that it was about "5-fold larger" than at base level.

Table 2. Seismic activity at Llaima summarized as RSAM (Real-time seismic amplitude) values and principal tremor frequencies. In times of relative quiet, baseline values at Llaima are ~ 20 RSAM units and 0.9 Hz. These data were taken from reports by OVDAS-SERNAGEOMIN (which omitted some time intervals).

Date Seismicity (RSAM units) Tremor frequency (Hz)
Jan 2002 28 0.9
Jun 2002 20 --
Sep 2002 57 1.2
Dec 2002 99 1.2 (during 18-20 Dec)
Mid-Jan 2003 93 --
Late Jan 2003 60 --
Apr 2003 92 1-2.2
18-19 Apr 2003 98 --

In September 2002, seismic instruments included two permanent stations (LLAI and MELI) located respectively on Llaima's S flank and S foot. In December 2002, there were two portable seismic receivers placed on the E flank at Lago Verde, which also recorded unrest. The seismicity continued to increase from December 2002 to mid-January 2003 (from ~70 to ~100 RSAM units). After that, it diminished and stabilized for about two months.

Sudden changes. A flight on 8 January 2003 led OVDAS to see remarkable changes since the late 2003 observations (figure 11). First, the dense fumarole emitted from the main crater was much stronger than the one seen 26 September 2002 (figure 11, top left). Second, the ice and snow had completely melted from main crater's internal walls. Third, complete melting of ice and snow had left exposed rock at both the summit and Pichillaima (figure 11, lower right). Fourth, numerous new crevasses had appeared in the cone's glaciers, particularly on the E flank. Down all flanks of the volcano, the 8 January observers saw ice falls, snow avalanches, ice detachments, and rockfalls.

Figure (see Caption) Figure 11. Contrasting views of Llaima's summit crater and Pichillaima as seen on 26 September 2002 (left, top and bottom, respectively) compared to 8 January 2003 (right, top and bottom, respectively). The scenes highlight differing conditions, particularly the melting of ice and snow. On 26 September 2002 snow covered most of the edifice. On 8 January 2003 there was an absence of significant ice and snow from parts of the crater walls, rim, and S flanks, and there were increased emissions of volcanic gases. Courtesy of OVDAS-SERNAGEOMIN.

Although the melting came at the time of the annual thaw, the situation on the volcano indicated that processes such as local heating accelerated the melting. Snow had fallen in early October 2002. The absence of ice and snow cover on both the shaded and unshaded sides of Llaima was cited as evidence indicating elevated rock temperature. Observers saw the melting and also noted a halt to any new accumulation of ice and snow deposits. The melting was attributed to magma at depth in the conduit, and considerable heat emerging at the locations where the ice melted.

The report issued 20 January 2003 noted that field work on Llaima's W side (Cherquenco-El Salto) had disclosed deep new crevasses in the glacial ice reaching 1.5 km long. These were affiliated with avalanching from near the main cone's summit to the cone's NW foot (~ 3 km long by 0.5 km wide). Observers also noticed continued signs of thawing, including the appearance of small fumaroles, which they again attributed to the volcano warming.

The next available reports, from the period 9-11 April, came from eye-witnesses. Rodrigo Marín of Conguillío national park, noted "an increase of fumarole activity in the main crater between 9 and 10 April, which was accompanied by ash emission." In addition, from the N slope (Captrén) people heard underground noises.

At 1330 on 10 April a teacher at Los Andes de Melipeuco elementary school noted three ash explosions that reached ~ 500 m above the main crater and dispersed NE. Several others observers noted ash-bearing emissions from the main crater, including one at 1340 and another at 1350. A park ranger noted that around 2100-2200 on 10 April strong and continuous explosions awoke him and ash began to fall on him in the N-slope sector of Captrén. Later, the explosions became more sporadic, and he heard sounds similar to those made by the motion of heavy machinery. This continued into the early morning of 11 April.

The director of the above-mentioned school reported to OVDAS that on 11 April at 0915 he saw "...continuing ash emission from the main crater." Finally, at 1100 on 11 April, OVDAS observatory (Cerro ñielol-Temuco) staff observed a vertical column, mainly of volcanic gases, which rose to about 600-700 m above the crater rim. This fed a large, horizontal, lenticular cloud ~ 30 km in diameter, the top of which rose to about 3,900 m altitude.

An 11 April helicopter flight disclosed a thin layer of pyroclastic material spread widely across the glaciers on the NE, E, SE, and SW flanks, visible out to distances of ~ 4 km. Impact craters in the ice testified to numerous bouncing and rolling projectiles. Scientists on that flight noted vigorous fumarolic activity and dense clouds with colors and odors indicating the presence of SO2 and HCl. At multiple spots, small fumaroles had sprouted from the crater walls. The crater floor contained a 50-m-diameter vent emitting gases, but no lava flows had emerged. Although the 9-11-April eruptions were modest, they prompted Llaima's hazard status to rise from Green to Yellow.

Figure 12 portrays further melting and exposure of underlying rock at both the summit (top) and Pichillaima (bottom) on 11 April. When photographed, the ice and snow at Pichillaima had receded by 1.0-1.5 km from its topographic high. Ice margins appeared sub-vertical and engulfed circular melt areas.

Figure (see Caption) Figure 12. Two vistas of Llaima on 11 April 2003 documenting the rapid ice recession and melting around the main crater and Pichillaima. (A) Rim and flanks of the summit and associated main crater standing with large areas ice free. (B) Pichillaima, nearly ice free and encircled by thick ice at the limit of ice melting. Courtesy of OVDAS-SERNAGEOMIN.

Other amazing photos taken 11 April 2003 revealed dramatic changes in glaciers and snow fields (figure 13). Many regions of the ice appeared to be in motion and undergoing acute mechanical failure. Numerous profound crevasses had emerged, including sets of broadly transverse, arcuate crevasses trending from glacial margins and extending well into their axial areas.

Figure (see Caption) Figure 13. Four views of Llaima from helicopter, taken on 11 April 2003 showing newly exposed rock surfaces, newly created ice-margins, and unstable, rapidly breaking glaciers. Llaima's comparatively temperate late-2002 to early-2003 eruptive phase correlated with these remarkable changes in its alpine glaciers. Courtesy of OVDAS-SERNAGEOMIN.

On 12-13 April 2003 the main crater issued intense pulsing fumarolic degassing at 1- to 3-minute intervals. Odors and celeste color were again indicative of SO2 and HCl components; such emissions were noted until 1500 on 13 April. Other processes on those days included mass wasting, sometimes with associated dust, apparent vibrations at the summit, and ballistic discharges from the main crater. At 1310 on 13 April, expulsions intensified and occurred at 1 minute intervals. Plumes blew E.

Continued observations resulted in the recommendation to maintain the Yellow status at least through 16 April as eruptions began to contain significant tephra. Volcanologists expressed concern that the volcano's glacial ice-cover could undergo further melting, which might lead to large and sudden outbursts of water (glacier bursts) traveling down local drainages.

On 16 April at 1453 OVDAS personnel in the Lago Verde area confirmed gaseous emissions were continuing to escape from the crater. They reported that at 1535 these emissions intensified and reached 200 m above the crater rim, with the plume blowing SE and being visible for ~ 8 km. They noted that at 1537 gaseous emissions escaped at Pichillaima. On the N (Captrén) side of the mountain at 1704 the observers saw gray-colored fumaroles. During 1130-1355 on 17 April from a point near the Lago Verde they perceived SO2 and HCl; they witnessed gas emissions to the NE reaching 200 m above the crater rim and spawning a plume visible for ~ 10 km.

The 20 and 23 April 2003 OVDAS reports discussed poor visibility but the permanent stations indicated high-amplitude tremor and considerable seismicity (eg., 98 RSAM units on 18 and 19 April). OVDAS staff interpreted these signals as due to fluids and gases moving in internal conduits. They also pointed out the absence of high- and low-frequency earthquake swarms, signals that generally precede emissions of ash. Small swarms of long-period earthquakes began, however, on 25 April.

Ascent during mid-April 2003. In mid-April 2003 Klaus Bataille (a physicist and seismologist teaching geophysics at the University of Concepción) and his students conducted field work on Llaima. Amid an interval of seismic and volcanic quiet on 18 April they ascended into the region of ice melt near the summit region, and made direct observations relevant to the issue of heat transport. Bataille made the following comments.

"A week after the explosion announced by the OVDAS, we (8 students and myself) went to install two broadband seismic stations to study the evolution of its activity, and we installed a GPS receiver as well. When we finished with the installation, it was a clear day and we decided to climb as much as we could. We began early in the morning [of 18 April] . . . [and] could see from the distance fumaroles coming from the crater, and several vents with vapor and gases coming out from different places, some 200-300 m below the crater, towards the N. We did not find any impediment to continue climbing, neither physical difficulties nor anomalous activity from the crater. Thus the whole group continued up to 300 m below the crater, where four persons stayed due to physical conditions, and five continued up to the crater. The persons who stayed (me included) realized that there was an incredible warm feeling while laying on the ground. This was due to the amount of vapor with some faint smell of sulphur. We could even take off our jackets and shirts, as long as we were laying flat. After lying for a while it was even too hot to [continue]. Fantastic feeling, lying almost on top of the volcano, with a tremendous view, feeling the warmth through the rocks."

Thus, on 18 April, Bataille and students affirmed the previously stated idea of heat emerging to cause the melting and leading to the sudden emergence of crevasses observed since December 2002. A later clarification from Bataille on the mode of heat transfer (viz., "conductive heating," passed through the rocks; or "convective heating," transported by warmed fluids such as gases) resulted in this statement: "I'm not convinced of 'conductive heating' as a direct source for the ice melting, because of the large amount of gases through the system. I'm inclined instead, to believe that melting of the ice is simply due to the large amount of vapor flowing through the loose rocks. However, I agree that [these] gases have to be produced while in contact with hot material, and in this sense [could] be affected by 'conductive heating.'"

Thus, Bataille observed that the rocks in the ice-melt zone around the summit were warm to the touch. He concluded that they were heated by deeper sources and water vapor transported the heat to the surface.

The scientists discussed their results in a subsequent conference paper (Bataille and others, 2003) and on their website, highlighting the seismic and GPS stations installed on Llaima's W and N sides. The former seismic station, near the Refuge Tucapel, began operating on 17-18 April. The latter seismic station, near Captrén, began operating on 19-20 April.

Their recordings lacked earthquakes that could be linked to deeper sources (no fractures nor seismo-tectonic events) during the period between April and the following 4 months. The whole period was dominated by a sequence of tremors due to the activity associated with the crater. Tremor energy decayed gradually in time. The frequencies involved were generally stable, though peculiar and without a good model for their genesis.

Reference. Bataille, K., Hermosilla, G., and Mora, D., 2003, (title translated from Spanish) Seismic activity of Llaima volcano: Dominated by phreatomagmatic sources?, 10th Chilean Geological Congress (10° Congreso Geológico), session 5, paper 63, (October 2003, Universidad de Concepción) (also cited in Revista geológica de Chile; ISSN 0716-0208)

Geologic Background. Llaima, one of Chile's largest and most active volcanoes, contains two main historically active craters, one at the summit and the other, Pichillaima, to the SE. The massive, dominantly basaltic-to-andesitic, stratovolcano has a volume of 400 km3. A Holocene edifice built primarily of accumulated lava flows was constructed over an 8-km-wide caldera that formed about 13,200 years ago, following the eruption of the 24 km3 Curacautín Ignimbrite. More than 40 scoria cones dot the volcano's flanks. Following the end of an explosive stage about 7200 years ago, construction of the present edifice began, characterized by Strombolian, Hawaiian, and infrequent subplinian eruptions. Frequent moderate explosive eruptions with occasional lava flows have been recorded since the 17th century.

Information Contacts: Hugo Alberto Moreno Roa, Gustavo Alejandro Fuentealba Cifuentes, Paola Andrea Peña Salazar, Erwin Edinson Medel Segura, Pedro Jorge Ortiz Hernandez, Beatriz Eliana Alarcón Avedaño, Chile Observatorio Volcanológico de los Andes del Sur-Servivio Nacional de Geologia y Mineria (Chile Volcanologic Observatory of the South Andes—National Service of Geology and Mining) (OVDAS-SERNAGEOMIN), Manantial 1710-Carmino del Alba, Temuco, Chile (URL: http://www.sernageomin.cl/); Servicio Nacional de Geología e Minería (SERNAGEOMIN), Av. Santa María 0104, Casilla 10465, Santiago, Chile (URL: http://www.sernageomin.cl/); Klaus Bataille, Departamento Ciencias de la Tierra, Universidad de Concepción, Víctor Lamas 1290, Casilla 160-C, Concepción, Chile (URL: http://www3.udec.cl/geologia/).


Manam (Papua New Guinea) — February 2004 Citation iconCite this Report

Manam

Papua New Guinea

4.08°S, 145.037°E; summit elev. 1807 m

All times are local (unless otherwise noted)


One minor eruption but otherwise low activity during February 2004

Activity at Manam's two summit craters remained low during February 2004. The summit area was cloud covered most of the month; however, when clear, both craters were observed releasing white vapor at weak to moderate rates. A single explosion occurred during the month, on 14 February at Southern Crater. A thick dark gray ash cloud and weak roaring noises accompanied the explosion. The ash cloud rose several hundred meters above the summit before drifting NW of the island, resulting in fine ashfall downwind. There was no nighttime glow observed.

Geologic Background. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys" channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.

Information Contacts: Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.


Rabaul (Papua New Guinea) — February 2004 Citation iconCite this Report

Rabaul

Papua New Guinea

4.271°S, 152.203°E; summit elev. 688 m

All times are local (unless otherwise noted)


1-17 February 2004-ash falls 30 km to the E

The eruptive activity at Tavurvur that began in early October 2002 ceased on 17 February 2004. From 1-17 February the activity was characterized by emissions of light to pale ash clouds accompanied by occasional moderate explosions that produced thick ash plumes. The ash plumes rose 1000-2000 m above the summit before being blown to the E and NE resulting in ashfall in the Duke of York islands, ~ 30 km E of Rabaul.

A slight change in wind direction resulted in fine ashfall over Rabaul Town and villages downwind on 6 and 13-15 February. Occasional weak roaring noises accompanied some of the explosions on 5 and 11 February. From 18 February until the month's end, Tavurvur was only releasing weak white vapor, with occasional blue vapor. Seismic activity between 1 and 17 February reflected the ash emissions at the summit. One high frequency event occurred on 5 February, located NE of the caldera. Ground deformation indicated a deflationary trend. The real-time GPS and electronic tilt site on Matupit Island, in the center of the caldera, showed a deflationary trend since the middle of the month.

Geologic Background. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor utilized by what was the island's largest city prior to a major eruption in 1994. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the east, where its floor is flooded by Blanche Bay and was formed about 1400 years ago. An earlier caldera-forming eruption about 7100 years ago is now considered to have originated from Tavui caldera, offshore to the north. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.

Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.


Ruang (Indonesia) — February 2004 Citation iconCite this Report

Ruang

Indonesia

2.3°N, 125.37°E; summit elev. 725 m

All times are local (unless otherwise noted)


Eruption on 25 September 2002 is the largest in Indonesia in many years

The 25 September 2002 eruption of Ruang (BGVN 27:10 and 28:08) was, according to the Darwin Volcanic Ash Advisory Center (VAAC), the largest in Indonesia for many years and was well observed by satellite sensors. The eruption cloud reached a height of ~ 20 km, and a pyroclastic flow toward the SE damaged an area 1.6 km². Although no village was hit by the pyroclastic flow, two were heavily damaged by very thick ash material.

The Darwin VAAC and Bureau of Meteorology have published images and animations of the eruption clouds (figure 2). The satellites and images included those from Aqua/MODIS, GMS Java Animation, and AVHRR sensors. Some ash clouds dispersed towards Singapore and Jakarta. A higher level cloud remained nearly stationary near the tropopause (the top of the troposphere, where most of the Earth's weather occurs). The highest cloud moved eastwards in the stratosphere. The color/shading reflects the strength of the detected ash signal.

Figure (see Caption) Figure 2. Night-time infrared image of the Ruang eruption processed to highlight volcanic ash. N is towards the top; the local island margins are shown, Sulawesi to the right and Borneo to the left. The enhanced areas disclose the W portion of the plume drifting over Borneo and the higher E ash and gas cloud nearly stationary over the eruption site. A third area of ash and ice cloud is nearly invisible near the bottom center. Courtesy of NASA, NOAA, and the Darwin VAAC.

The TOMS scientists published an image on their website (figure 3), described as follows: "The TOMS overpass on September 25 was too early to capture the fresh eruption cloud, but ash and SO2 were evident on the following day. The aerosol signal over S Borneo is at least partly due to smoke from biomass burning; the ash cloud from Ruang can be seen over NE Borneo. A data gap may be obscuring any SO2 or ash immediately W of Ruang."

Figure (see Caption) Figure 3. Ruang erupted on 25 September 2002. A pass the next day of the Earth Probe satellite with the Total Ozone Mapping Spectrometer (TOMS) instrument yielded this map of SO2 concentrations. Courtesy of Simon Carn and Arlin Krueger.

Geologic Background. Ruang volcano, not to be confused with the better known Raung volcano on Java, is the southernmost volcano in the Sangihe Island arc, north of Sulawesi Island. The 4 x 5 km island volcano rises to 725 m across a narrow strait SW of the larger Tagulandang Island. The summit contains a crater partially filled by a lava dome initially emplaced in 1904. Explosive eruptions recorded since 1808 have often been accompanied by lava dome formation and pyroclastic flows that have damaged inhabited areas.

Information Contacts: Darwin Volcanic Ash Advisory Center (VAAC), Commonwealth Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Nia Haerani, Directorate of Volcanology and Geological Hazards (formerly VSI), Jalan Diponegoro No 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Simon A. Carn and Arlin Krueger, Joint Center for Earth Systems Technology (NASA/UMBC), University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA (URL: https://so2.gsfc.nasa.gov/).


Ruapehu (New Zealand) — February 2004 Citation iconCite this Report

Ruapehu

New Zealand

39.28°S, 175.57°E; summit elev. 2797 m

All times are local (unless otherwise noted)


Strategy, prediction, and management of crater-lake overflow and powerful lahar

Citing risks about a lahar expected when an ash dam surrounding Ruapehu's crater collapses, the New Zealand government decided that draining, sluicing, or siphoning the volcano's crater lake to reduce the danger was too hazardous, reported Jo-Marie Brown in The New Zealand Times (10, 17, and 19 March 2004). The articles noted that, instead, the government decided to bolster extensive safety measures already in place around the volcano, including improving alarm systems. These new measures should provide warnings of lahar occurrences at least an hour and a half in advance. The government also elected to strengthen bridges and build an embankment to withstand lahars.

The New Zealand Department of Conservation has an extensive outreach to discuss the crater lake-lahar problem (figure 26). They point out that the crater lake on Mt. Ruapehu was refilling after it was emptied by eruptions in 1995 and 1996. This lake lies over the main active vent of the volcano. Before the eruptions, the level of the crater lake was controlled by an outlet that drained water across a sill of lava into the head of the Whangaehu Valley. During the 1995-96 eruptions, this outlet was blocked by 7 m of tephra (fine ash particles and other larger materials ejected by the volcano).

Figure (see Caption) Figure 26. This publicly distributed image was created in response to the threat of lahars descending the Whangaehu Valley at Ruapehu in 2004. In addition to local geography, it shows the location of warning sensors, key bridges, and a critical embankment ("bund") to direct the lahars. The associated information discusses warnings of impending lahars on the order of 1-2 hours before they arrive at critical downstream sites. Courtesy of the New Zealand Department of Conservation.

The Department also noted that since March 1999, the crater lake had risen 52 m and was filling at a rate of 5,300 m3 per day. On 15 March 2004 the lake's surface elevation was reported at 2,527.6 m above sea level. In mid-March 2004 the Department also reported that the lake was then ~ 96% full, a point ~ 2 m below the base of the tephra dam emplaced by the 1995-6 eruptions (the old overflow point). The predicted time for the lake to completely fill was given as early April 2004 to November 2004. An estimated 60 lahars have swept down the mountain's southern side through the Whangaehu Valley in the past 150 years. A lahar in 1953 killed 151 people at Tangiwai. The Department of Conservation reported additional details regarding the crater lake: there was low to normal hydrothermal activity; the water temperature on 15 March 2004 was 35°C; and the lake color was gray.

Geologic Background. Ruapehu, one of New Zealand's most active volcanoes, is a complex stratovolcano constructed during at least four cone-building episodes dating back to about 200,000 years ago. The dominantly andesitic 110 km3 volcanic massif is elongated in a NNE-SSW direction and surrounded by another 100 km3 ring plain of volcaniclastic debris, including the Murimoto debris-avalanche deposit on the NW flank. A series of subplinian eruptions took place between about 22,600 and 10,000 years ago, but pyroclastic flows have been infrequent. A single historically active vent, Crater Lake (Te Wai a-moe), is located in the broad summit region, but at least five other vents on the summit and flank have been active during the Holocene. Frequent mild-to-moderate explosive eruptions have occurred in historical time from the Crater Lake vent, and tephra characteristics suggest that the crater lake may have formed as early as 3,000 years ago. Lahars produced by phreatic eruptions from the summit crater lake are a hazard to a ski area on the upper flanks and to lower river valleys.

Information Contacts: The New Zealand Herald, PO Box 32, Auckland, New Zealand (URL: http://www.nzherald.co.nz/); New Zealand Department of Conservation, Private Bag, Turangi, New Zealand (URL: http://www.doc.govt.nz/); Institute of Geological & Nuclear Sciences (IGNS), Private Bag 2000, Wairakei, New Zealand (URL: http://www.gns/cri.nz/).


Soufriere Hills (United Kingdom) — February 2004 Citation iconCite this Report

Soufriere Hills

United Kingdom

16.72°N, 62.18°W; summit elev. 915 m

All times are local (unless otherwise noted)


Ash to 7 km altitude on 3 March 2004; pyroclastic flows reached the sea

The Soufrière Hills volcano was quiet for the last few months of 2003, following activity in May and July that included significant dome growth (BGVN 28:10 and 28:12). Light ash-venting had last occurred during a period of low-amplitude tremor 3-8 October. A seismic event in mid-January 2004 and a period of tremor and mudflow activity in late February 2004 were followed by renewed eruptive activity on 3 March 2004.

Between 1 October and 18 December 2003 no dome growth was observed, and only a few earthquakes per week were recorded. Beginning 18 December 2003, SO2 emissions increased markedly from the previous month's average of 500 tons/day (t/d), reaching 3,600 t/d (see table 53). On 18 January 2004, a swarm of low-amplitude long-period (LP) earthquakes began, with ~1,000 separate events over an interval of 36 hours. Fewer than 40 of these earthquakes triggered the automatic seismic-detection systems. Another swarm occurred on 30 January, this time lasting about 30 hours. Again, instruments recorded ~1,000 separate events; these, however, were much weaker and only four triggered the detection systems.

Table 53. Summary of SO2 emissions recorded at Soufrière Hills, 5 December 2003 to 12 March 2004, using an array of three scanning UV spectrometers. Courtesy of Montserrat Volcano Observatory.

Date SO2 emissions (metric tons/day)
05 Dec-11 Dec 2003 300-900
12 Dec-18 Dec 2003 500-3,600
19 Dec-25 Dec 2003 --
26 Dec-01 Jan 2004 500
02 Jan-08 Jan 2004 300
09 Jan-15 Jan 2004 200-590
16 Jan-22 Jan 2004 440 on 22 January (equipment servicing on other days)
23 Jan-29 Jan 2004 500-700
30 Jan-05 Feb 2004 439-1017
06 Feb-12 Feb 2004 350-450
13 Feb-19 Feb 2004 350-650
20 Feb-26 Feb 2004 496-920
27 Feb-04 Mar 2004 480-820
05 Mar-12 Mar 2004 340-1250

A period of low-level tremor, consisting of many small LP earthquakes, lasted for about 36 hours beginning 21 February. On 24 February heavy rainfall (10 mm in 2.5 hours) resulted in mudflow activity in the Belham valley; signs of mudflows were also observed in Plymouth.

Beginning the week of 27 February, activity increased significantly. On 2 March, a period of low-level tremor included some small hybrid earthquakes. The tremor continued until afternoon on 3 March, when, at around 1444, seismicity greatly increased and an explosion and collapse event occurred. According to reports from the Montserrat Volcano Observatory (MVO) this was the most significant event since the collapse event of 12-13 July 2003.

The event on 3 March 2004 produced ash clouds that reached altitudes of about 7 km above sea level, and pyroclastic flows were observed in the Tar River, with at least two incidents of flows reaching the sea. Seismicity returned to close to background levels by 1525, but vigorous ash venting continued until the following morning. Low-level tremor accompanied by hybrid earthquakes continued for the next 18 hours, including a series of hybrid earthquakes during the evening of 3 March.

Visual observations first suggested that the 3 March explosion removed the small dome that had grown in the collapse scar in late July 2003. Photographs taken on 28 February and 5 March showed the 3 March collapse to have also removed part of the NW dome remnant originally built up during 1995-1998.

After 3 March, activity remained elevated for several days. A period of low-level tremor occurred on 4 March, beginning at around 1300 and lasting three hours. On 5 March a small explosion was recorded at 1009, followed by a period of ash venting. Between 5 and 12 March activity returned to lower levels, with 1 LP and 15 hybrid earthquakes recorded. On 10 March, however, there was a short (10-20 minutes) period of elevated seismicity early in the morning; later in the day fresh pyroclastic-flow deposits were observed in the upper reaches of the Tar River Valley. During the second half of the week, short episodes of ash and steam venting were periodically observed, and ash fallout occurred as far N as St. Georges Hill.

On 15 March, the Washington VAAC reported a plume of ash extending to the W from the summit. The following day MVO reported a plume extending 250 km (135 nautical miles) W of the volcano. SO2 emissions fluctuated during February and the first two weeks of March, peaking at 1017 t/d on 1 February and 1250 t/d on 9 March (table 2).

A beautifully illustrated look at the eruption from 1995 to present is now available (Kokelaar, 2002; Druitt and Kokellar, 2002).

References. Kokelaar, B.P., 2002, Setting, chronology and consequences of the eruption of Soufrière Hills Volcano, Montserrat (1995-1999), in Druitt, T.H. and Kokelaar, B.P., eds., 2002: The eruption of the Soufrière Hills Volcano, Montserrat from 1995 to 1999. Geological Society London, Memoir No. 21, p. 1-43.

Druitt, T.H. and Kokelaar, B.P., eds., 2002: The eruption of the Soufrière Hills Volcano, Montserrat from 1995 to 1999. Geological Society London.

Geologic Background. The complex, dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. The volcano is flanked by Pleistocene complexes to the north and south. English's Crater, a 1-km-wide crater breached widely to the east by edifice collapse, was formed about 2000 years ago as a result of the youngest of several collapse events producing submarine debris-avalanche deposits. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits, including those from an eruption that likely preceded the 1632 CE settlement of the island, allowing cultivation on recently devegetated land to near the summit. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but no historical eruptions were recorded until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption.

Information Contacts: Montserrat Volcano Observatory (MVO), Fleming, Montserrat, West Indies (URL: http://www.mvo.ms/); Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ssd.noaa.gov).


Stromboli (Italy) — February 2004 Citation iconCite this Report

Stromboli

Italy

38.789°N, 15.213°E; summit elev. 924 m

All times are local (unless otherwise noted)


After 10 February 2004, explosions at upper limit of that typically seen

According to aviation reports from the U.S. Air Force, the web camera at Stromboli captured shots of light ash emissions on 7 and 11 November 2003. In both cases plumes rose to ~ 2.5 km elevation. The Stromboli Web video camera showed a small explosion on 10 December 2003 that produced a plume to a height of ~ 1 km above the volcano. No ash was visible on satellite imagery.

The Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Catania reported that explosive activity at Stromboli's three summit craters increased after 10 February 2004, leading to significant growth of the cinder cones inside the craters. Several powerful explosions, especially from Crater 1 (the NE crater) and Crater 3 (the SW crater), sent scoriae 200 m above the rims. These powerful explosions led to fallout of fresh bombs and lapilli on Il Pizzo Sopra la Fossa (an area atop the volcano about 100 m above the crater terrace) in early March. As of 8 March, Strombolian activity was occurring at the volcano, with variations in the number and frequency of explosions within normally observed limits, and the intensity of explosions at the higher limit of commonly observed activity.

Geologic Background. Spectacular incandescent nighttime explosions at this volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small island is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period took place between about 13,000 and 5,000 years ago. The active summit vents are located at the head of the Sciara del Fuoco, a prominent horseshoe-shaped scarp formed about 5,000 years ago due to a series of slope failures that extend to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded for more than a millennium.

Information Contacts: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania Piazza Roma 2, 95123 Catania, Italy (URL: http://www.ct.ingv.it/); Toulouse VAAC, Météo-France, 42 Avenue G. Coriolis, 31057 Toulouse, France (URL: http://www.meteo.fr/vaac/); AGI Online news service, Italy (URL: http://www.agi.it/).


Ulawun (Papua New Guinea) — February 2004 Citation iconCite this Report

Ulawun

Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)


Tabulation of aviation reports issued during 2000-mid-2003

Activity on Ulawun occurs frequently and is monitored and reported from several sources including the Rabaul Volcano Observatory (RVO), the Darwin Volcanic Ash Advisory Center (VAAC), the U.S. Air Force Weather Agency (AFWA), and imagery from several satellites including NOAA GMS (daylight) and MODIS (infrared). The continuing activity after an eruption on 28 September 2000 (see BGVN 25:08) resulted in BGVN reports every few months since that event (BGVN reports on Ulawun have appeared in nine subsequent issues through the end of 2003).

This issue supplements the Bulletin reports with those from the Darwin VAAC archives (table 2), which included information provided from ground, airborne, and space-based sensing. RVO reports that Ulawun remained quiet during February 2004. Emissions from the main vent consisted of white vapor being released at weak to moderate rates. No noise or night-time glow were reported during the month. No emission was reported from the two N-valley vents. Seismicity was at a low level.

Table 2. Dates of issue and the principal comments in Darwin VAAC reports concerning Ulawun, September 2000-July 2003. Similar or duplicate messages are not shown. In many cases ash cloud trajectory information has been omitted. On this table, the distance unit Nautical Miles (NM) has not been converted to kilometers (1 NM = 1.852 km (exactly)). Courtesy of the Darwin VAAC.

Date Source Eruption Details / Ash Cloud
28 Sep 2000 AIREP, AIR NIUGINI, ANK. Volcanic Activity reported at 28/2005Z - Ash plume to 11 km, rapid growth at top, spreading out 30 NM to N to SW. ASH CLOUD: Latest satellite imagery shows possible ash cloud extending 60 NM in an arc from ENE to the WSW.
29 Sep 2000 AIREP, AIR NIUGINI, ANK. There is evidence of volcanic ash on satellite imagery from 28/1800Z
30 Sep 2000 AIREP/Geological Survey Papua New Guinea. The Geological Survey confirms this eruption and notes that limited evacuations have commenced with the prospect of further seismic and eruptive activity. However 29/2230Z ash emissions were limited to infrequent puffs.
01 Oct 2000 AIREP/Geological Survey Papua New Guinea. A Geological Survey report (at 01/0001Z) noted the summit activity was relatively quiet for last 24 hours. QANTAS AIREP at 30/0501Z also observed the lack of activity.
29 Apr 2001 AIREP from PNG at 292130Z. Aircraft observed smoke cloud up to 9 km and drifting NW and SW direction out to 50/70 miles radius. ASH CLOUD: Satellite imagery [29/2132Z] shows possible volcanic plume extending 65 NM to the W and 30 NM to the N and S.
30 Apr 2001 -- Examination of latest satellite imagery [30/0530Z] indicates significant eruption has ceased. Ash plume may reach 14 km.
01 May 2001 Visual and infra-red GMS and NOAA satellite imagery, RVO. RVO advise remains on a high alert level with further eruptions possible. ASH CLOUD: There is no evidence of ash cloud at this time, but widespread cloud in the area is making detection difficult.
03 May 2001 AIREP from PNG 29/4/2001 2130Z. Visual and infra-red GMS and NOAA satellite imagery, RVO. A report by an aircraft of volcanic activity [on 29 April] at about 2130Z with smoke/ash cloud up to 9 km, and confirmed by the RVO and satellites surveillance, initiated a series of Volcanic Advisories. The latest report from RVO this morning states that activity has moderated. ASH CLOUD: Satellite surveillance has not identified any ash cloud since the initial eruption.
28 Aug 2001 GMS/NOAA Satellite Imagery. Ash observed on satellite imagery. Analysis indicates eruption is low level. ASH CLOUD: Ash plume 5 NM wide, extending 15 miles to the S of the summit. Ash expected to be below 4 km.
12 Sep 2002 NOAA/GMS satellite imagery. Small low level plume detected on visible satellite imagery at 11/2100Z. Plume extended 60 NM from summit in the sector NNW to NNE.
18 Sep 2002 GMS satellite imagery. Low level plume detected on visible satellite imagery at 18/2100Z. ASH CLOUD: Very thin plume extends 40 NM to the WSW
19 Sep 2002 GMS satellite imagery. Plume can no longer be detected on latest GMS imagery.
27 Sep 2002 GMS satellite imagery. Ash plume observed on satellite imagery [27/]2030Z. ASH CLOUD: Narrow ash cloud extends 40 NM to SW
28 Sep 2002 GMS satellite imagery. Ash plume observed on satellite imagery 2130Z. ASH CLOUD: Narrow ash cloud extends 20 NM to the NNW.
15 Oct 2002 GMS satellite imagery. Low level ash plume observed on satellite imagery 15/2225Z. ASH CLOUD: Ash plume extends 20 NM N of volcano. Winds indicate plume probably low level.
21 Oct 2002 AIREP PZ-ANF, GMS imagery. Smoke reported in area, and plume observed via GMS imagery. ASH CLOUD: Cloud up to 4 km, extending 5 NM, 30 NM wide to SE.
01 Nov 2002 AIREP. Smoke observed 01/0042Z drifting to NW of volcano at 3 km.
02 Nov 2002 AIREP AIR NIUGINI. Ash observed 02/2030Z drifting to ESE of volcano to 3 km.
11 Apr 2003 NOAA and GMS imagery. Plume evident on 10/2019Z and 11/0357Z NOAA image[s], height estimated below 3 km.
14 Apr 2003 GMS imagery. Possible plume evident on 13/2032Z, 13/2132Z and 13/2225Z [images], height estimated below 3 km
26 Apr 2003 GMS imagery. Possible plume evident on 26/0325Z MODIS as reported by KGWC/ Washington VAAC, height estimated below 4 km.
30 Apr 2003 GMS and MODIS imagery. Possible narrow low level plume evident on 30/0010Z MODIS and 30/0230Z GMS visible image[s], extending 30 NM WNW, height estimated below 3 km.
03 May 2003 KGWC. Ash/steam plume observed on 02/2026Z F13 DMSP Imagery. Plume extends 80 NM W of volcano, height to 4 km.
04 May 2003 NOAA satellite imagery. Thin low level plume observed on 04/2053Z. Plume extends 10 NM SW of Ulawun, height estimated at 4 km.
06 May 2003 GMS satellite imagery. Thin low level plume observed on 06/2032Z.
01 Jun 2003 GOES9 satellite imagery. Thin low level plume observed on [May] 31/2325Z.
18 Jun 2003 AFWA. Faint ash/steam plume seen on 18/2206Z satellite imagery.
20 Jun 2003 NOAA 17. Faint plume seen on NOAA 17 20/0004Z satellite imagery.
20 Jun 2003 NOAA 15. Faint plume seen 20/2050Z.
23 Jun 2003 NOAA 15. Faint plume seen on 23/2120Z.
24 Jun 2003 NOAA 15. Faint plume seen on 24/2057Z.
26 Jun 2003 MODIS. Faint plume seen on 26/0005Z extending 25 NM SW, height estimated at 4 km.
28 Jun 2003 NOAA 15. Faint plume seen on 28/2101Z.
02 Jul 2003 NOAA 15. Thin ash plume to 5 km extending 25 NM WSW of summit on 02/2108Z.
13 Jul 2003 AFWA. Thin ash plume to 4 km moving to the W at 10 knots [10 NM/hour or 18 km/hour].
22 Jul 2003 GOES9. Possible ash plume seen on 22/0130Z visible GOES imagery, extending 30 NM to NW, height estimated at 3 km.

The VAAC reports contain numerous abbreviations; however, a few of the terms here are in widespread use referring to satellites, meteorology, and various related agencies (NOAA, AFWA, GOES9, MODIS, and KGWC . . . DMSP Imagery, etc.) or AIREP (atmospheric conditions reported from aircraft). "RVO" stands for Rabaul Volcano Observatory. Other terms may be less familiar: "AIR NIUGINI, ANK." refers to a commuter plane in the fleet of the national airline based in Papua New Guinea. The stated dates and times are not local ones, but instead refer to those at the zero (prime) meridian. For example, 04/2240Z means the fourth day of the stated month at 2240 UTC (i.e. "Z," spoken as Zulu, is shorthand for Coordinated Universal Time (UTC).

Geologic Background. The symmetrical basaltic-to-andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. The volcano, also known as the Father, rises above the N coast of the island of New Britain across a low saddle NE of Bamus volcano, the South Son. The upper 1,000 m is unvegetated. A prominent E-W escarpment on the south may be the result of large-scale slumping. Satellitic cones occupy the NW and E flanks. A steep-walled valley cuts the NW side, and a flank lava-flow complex lies to the south of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.

Information Contacts: Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea; Darwin Volcanic Ash Advisory Center (VAAC), Commonwealth Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/).


Witori (Papua New Guinea) — February 2004 Citation iconCite this Report

Witori

Papua New Guinea

5.576°S, 150.516°E; summit elev. 724 m

All times are local (unless otherwise noted)


Two explosions on 24 February 2004, otherwise quiet during that month

Pago was mainly quiet throughout the month of February 2004. However, two explosions were reported in the early hours of 24 February. The explosions were accompanied by thick dark grey ash clouds from the lower and upper vents. The ash clouds drifted SW of the volcano resulting in fine ashfall downwind. Jet-like noises were also heard at 0140 on 24 February accompanying the explosions. A weak glow was visible from the lower vents.

Geologic Background. The 5.5 x 7.5 km Witori caldera on the northern coast of central New Britain contains the young historically active cone of Pago. The Buru caldera cuts the SW flank of Witori volcano. The gently sloping outer flanks of Witori volcano consist primarily of dacitic pyroclastic-flow and airfall deposits produced during a series of five major explosive eruptions from about 5600 to 1200 years ago, many of which may have been associated with caldera formation. The post-caldera Pago cone may have formed less than 350 years ago. Pago has grown to a height above that of the Witori caldera rim, and a series of ten dacitic lava flows from it covers much of the caldera floor. The youngest of these was erupted during 2002-2003 from vents extending from the summit nearly to the NW caldera wall.

Information Contacts: Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.

Atmospheric Effects

The enormous aerosol cloud from the March-April 1982 eruption of Mexico's El Chichón persisted for years in the stratosphere, and led to the Atmospheric Effects section becoming a regular feature of the Bulletin. Descriptions of the initial dispersal of major eruption clouds remain with the individual eruption reports, but observations of long-term stratospheric aerosol loading will be found in this section.

Atmospheric Effects (1980-1989)  Atmospheric Effects (1995-2001)

Special Announcements

Special announcements of various kinds and obituaries.

Special Announcements  Obituaries

Misc Reports

Reports are sometimes published that are not related to a Holocene volcano. These might include observations of a Pleistocene volcano, earthquake swarms, or floating pumice. Reports are also sometimes published in which the source of the activity is unknown or the report is determined to be false. All of these types of additional reports are listed below by subject.

Additional Reports  False Reports