Smithsonian / USGS Weekly Volcanic Activity Report

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday and averaging 16 reported volcanoes, this is not a comprehensive list of all eruptions this week, but rather a summary of activity that meet criteria discussed in the "Criteria and Disclaimers" section below.

Volcanic activity reported here is preliminary and subject to change. Carefully reviewed, detailed narratives over longer time periods are published as reports of the Bulletin of the Global Volcanism Network available through volcano profile pages.

Smithsonian / USGS Weekly Volcanic Activity Report for the week of 19 October-25 October 2011
Name	Country	Volcanic Province	Eruption Start Date	Report Status
Hierro	Spain	Canary Volcanic Province	—	New
Ranakah	Indonesia	Sunda Volcanic Arc	—	New
Sangay	Ecuador	Andean Northern Volcanic Arc	2019 Mar 26	New
Sheveluch	Russia	Eastern Kamchatka Volcanic Arc	1999 Aug 15	New
Tungurahua	Ecuador	Andean Northern Volcanic Arc	—	New
Aira	Japan	Ryukyu Volcanic Arc	2017 Mar 25	Continuing
Cleveland	United States	Aleutian Ridge Volcanic Arc	—	Continuing
Dukono	Indonesia	Halmahera Volcanic Arc	1933 Aug 13	Continuing
Etna	Italy	Sicily Volcanic Province	—	Continuing
Fuego	Guatemala	Central America Volcanic Arc	2002 Jan 4	Continuing
Karymsky	Russia	Eastern Kamchatka Volcanic Arc	—	Continuing
Kilauea	United States	Hawaiian-Emperor Hotspot Volcano Group	—	Continuing
Kizimen	Russia	Eastern Kamchatka Volcanic Arc	—	Continuing
Manam	Papua New Guinea	Bismarck Volcanic Arc	2014 Jun 29	Continuing
Popocatepetl	Mexico	Trans-Mexican Volcanic Belt	2005 Jan 9	Continuing
Puyehue-Cordon Caulle	Chile	Andean Southern Volcanic Arc	—	Continuing
Santa Maria	Guatemala	Central America Volcanic Arc	1922 Jun 22	Continuing
Suwanosejima	Japan	Ryukyu Volcanic Arc	2004 Oct 23	Continuing

All times are local unless otherwise stated.

Hierro (Spain) | 19 October-25 October 2011 | New Activity / Unrest Cite this Report

Hierro
Canary Volcanic Province

Instituto Geográfico Nacional (IGN) reported that during 19-25 October tremor continued to be registered by every seismic station on El Hierro Island; 270 seismic events were registered and located. The mean amplitude was lower than during previous days but indicated that the submarine eruption continued. Since 21 October, most of the events were located in the N part of the island, aligned NNW-SSE from the center of the island to around 13 km offshore. Most of these earthquakes occurred around 20-25 km depth. Superficial analysis of GPS deformation data from the last few days of the reporting period showed different behaviors between the stations located at the N of the island and the station located at the S, close to the submarine eruptive vent.

Source: Instituto Geográfico Nacional (IGN)

Ranakah (Indonesia) | 19 October-25 October 2011 | New Activity / Unrest Cite this Report

Ranakah
Sunda Volcanic Arc

CVGHM reported that throughout September and during 1-12 October diffuse white plumes rose 10-15 m above the Anak Ranakah lava dome. Plumes were not observed during 13-21 October. Starting on 1 July, seismicity had increased to a peak level on 15 August then declined through 20 October. Based on visual observations, seismicity, and deformation data, CVGHM lowered the Alert Level to 2 (on a scale of 1-4) on 22 October.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Sangay (Ecuador) | 19 October-25 October 2011 | New Activity / Unrest Cite this Report

Sangay
Andean Northern Volcanic Arc

Based on analyses of satellite imagery, the Washington VAAC reported that on 25 October a gas plume from Sangay, which possibly contained ash, drifted 75 km E. Ash was not identified in subsequent images.

Source: Washington Volcanic Ash Advisory Center (VAAC)

Sheveluch (Russia) | 19 October-25 October 2011 | New Activity / Unrest Cite this Report

Sheveluch
Eastern Kamchatka Volcanic Arc

KVERT reported that seismic activity at Shiveluch was moderate during 13-18 October and indicated that possible ash plumes rose to altitudes of 8-10.5 km (26,200-34,400 ft) a.s.l. Technical reasons prevented seismic data collection during 19-21 October. Ground-based observers noted hot avalanches in the lava dome area during 13-16 October, and that plumes from those avalanches rose to an altitude of 6 km (19,700 ft) a.s.l. Satellite imagery showed a large daily thermal anomaly over the lava dome and ash plumes that drifted 75 km E on 14 and 16 October. The Aviation Color Code remained at Orange.

Based on information from KEMSD, the Tokyo VAAC reported that on 23 October an eruption produced a plume that rose to an altitude of 7.3 km (24,000 ft) a.s.l. The altitude was based on seismic analysis. An eruption on 24 October noted by KVERT produced a plume that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

Tungurahua (Ecuador) | 19 October-25 October 2011 | New Activity / Unrest Cite this Report

Tungurahua
Andean Northern Volcanic Arc

Based on a pilot observation, the Washington VAAC reported that on 24 October an ash plume from Tungurahua rose to an altitude of 7.3 km (24,000 ft) a.s.l. and drifted W. Ash was not observed in satellite imagery. [A 9 November VAAC report stated that IG noted no ash emissions from Tungurahua since June.]

Source: Washington Volcanic Ash Advisory Center (VAAC)

Aira (Japan) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Aira
Ryukyu Volcanic Arc

Based on information from JMA, the Tokyo VAAC reported that during 20-25 October explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-3.4 km (6,000-11,000 ft) a.s.l. and drifted W, NW, E, and SE. Pilots observed ash plumes that rose to altitudes of 3 and 1.5 km (10,000 and 5,000 ft) a.s.l. on 23 and 25 October, respectively. The plumes drifted SE on both days.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Cleveland (United States) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Cleveland
Aleutian Ridge Volcanic Arc

AVO reported that during 19-23 October cloud cover over Cleveland prevented views of the lava dome in the summit crater. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Dukono (Indonesia) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Dukono
Halmahera Volcanic Arc

Based on analyses of satellite imagery, the Darwin VAAC reported that on 22 October ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 110-185 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Etna (Italy) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Etna
Sicily Volcanic Province

Sezione di Catania - Osservatorio Etneo reported that the seventeenth paroxysmal eruptive episode of 2011 took place at the New SE Crater (New SEC) of Etna during the evening of 23 October. Weak explosive activity was recorded at 1913, and at about 1935 small anomalies appeared in images recorded by thermal cameras. Explosive activity rapidly intensified at 1940 and by 2007 that crater was completely filled with lava. The lava overflowed through a breach in the E crater rim and traveled towards the Valle del Bove.

At 2026, Strombolian activity transitioned to continuous lava fountains that rose a few tens of meters above the crater rim. At 2036, a vent opened on the SE flank of the cone, producing a second lava fountain, leading to a significant increase in the lava effusion rate. The height of the lava fountains significantly increased after 2100, reaching 300 m above the crater. At about 2130, a third vent became active within the New SEC, possibly near the N rim. Abundant amounts of tephra fell on the E flank of the cone, forming a dense curtain, while large incandescent blocks rolled to the base of the cone on more gently sloping terrain. At approximately 2229 two lightning flashes near the crater were observed. After 2230 both effusive and explosive activity showed a marked reduction, changing again into Strombolian activity around 2300, and ceasing altogether at 2315.

The lava flow continued to advance towards the Valle del Bove until about 0040 on 24 October and stagnated just upslope of Monte Centenari (at 1,900 m a.s.l.). The area most heavily affected by the tephra (ash and small scoriaceous lapilli) fall was the E flank of Etna, including the N portion of the towns of Zafferana (about 10 km to the E), Milo (about 11 km ESE), and Fornazzo (10 km E), downslope across Santa Venerina (SE flank) and Dagala del Re (14 km ESE) to Giarre (~17 km E) and Riposto (18 km E), as well as nearby villages.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

Fuego (Guatemala) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Fuego
Central America Volcanic Arc

INSIVUMEH reported that during 20-21 October explosions from Fuego produced shock waves that were detected nearby, rumbling sounds, and ash plumes that rose 500 m above the crater and drifted W. Incandescence emanated from the crater at night, and avalanches traveled SW into the Taniluyá, Ceniza, and Trinidad drainages. On 23 October, the Washington VAAC reported that an ash plume was observed in satellite imagery.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)

Karymsky (Russia) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Karymsky
Eastern Kamchatka Volcanic Arc

KVERT reported that seismic activity continued at a moderate level at Karymsky during 14-21 October, and indicated that possible ash plumes rose to an altitude of 3.3 km (10,800 ft) a.s.l. during 13-15 October and to lesser altitudes the other days of the week. Satellite imagery showed a thermal anomaly on the volcano on 14 and 16 October. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Kilauea (United States) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Kilauea
Hawaiian-Emperor Hotspot Volcano Group

During 19-25 October, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby. At the E rift zone, incandescence emanated from the 21 September fissure on the upper E flank of the Pu'u 'O'o cone and lava flows remained active on the flow field to the SE of Pu'u 'O'o. Vents on the E and W edges of crater floor were incandescent.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Kizimen (Russia) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Kizimen
Eastern Kamchatka Volcanic Arc

KVERT reported that during 14-21 October the magnitudes of the volcanic earthquakes at Kizimen decreased, as well as the numbers, down to 22-60. Video data showed ashfall on the flanks during 14-15 October, and that a large lava flow on the NE flank continued to effuse. A thermal anomaly on the volcano was detected daily in satellite images. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Manam (Papua New Guinea) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Manam
Bismarck Volcanic Arc

Based on analysis of satellite imagery, the Darwin VAAC reported that during 19-21 October ash plumes from Manam rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted 150-220 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Popocatepetl (Mexico) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Popocatepetl
Trans-Mexican Volcanic Belt

CENAPRED reported that during 19-23 October steam-and-gas emissions rose from Popocatépetl. Emissions during 23-25 October occasionally contained small amounts of ash.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Puyehue-Cordon Caulle (Chile) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Puyehue-Cordon Caulle
Andean Southern Volcanic Arc

Based on seismicity during 19-25 October, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, mostly continued at a low level. Seismicity did increase during the last few days of the reporting period.

Plumes visible with an area web camera rose no higher than 2 km above the crater during 19-20 October. A small plume visible in satellite imagery on 19 October drifted 50 km E and a diffuse ash plume drifted 150 km NE and SE. On 20 October a small plume drifted 70 km E.

At night on 22 October incandescence emanated from the crater, possibly from active lava flows reported during the previous few days. At 0311 an explosion generated a plume that rose 4.5 km above the crater as well as increased incandescence from the crater. An ash plume observed in satellite imagery drifted 120 km W and NW, and a diffuse ash plume drifted 250 km NE and SE. During the day a white plume rose 3 km above the crater. Satellite imagery showed a plume that drifted 125 km NE, then dissipated NE and SE. On 24 October, a plume rose 6 km above the crater. Satellite imagery showed a plume drifting 125 km NE and a diffuse ash plume drifting 280 km in the same direction. The next day white plumes did not rise higher than 7.5 km above the crater and satellite imagery showed a plume that drifted 100 km NW and SW. The Alert Level remained at Red.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Santa Maria (Guatemala) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Santa Maria
Central America Volcanic Arc

Based on analyses of satellite imagery, the Washington VAAC reported that on 25 October a narrow ash plume from Santa María's Santiaguito lava dome complex rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted 30 km WNW.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Suwanosejima (Japan) | 19 October-25 October 2011 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Volcanic Arc

Based on a pilot observation, the Tokyo VAAC reported that on 14 October an ash plume from Suwanose-jima rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted SE. Ash was not detected in satellite imagery.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

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Criteria & Disclaimers

Criteria

The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:

- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.

Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.

It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.

Disclaimers

1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are cover longer time periods and are more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.

2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.

3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.

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