Activity for the week of 2 May-8 May 2012
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, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
New Activity / Unrest
| Komba Island (Indonesia)
| 7.791°S, 123.585°E
| Elevation 633 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 2-4 May ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 37 km NW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
Based on analyses of satellite images, AVO reported on 4 May that the small lava dome recently emplaced in Cleveland's summit crater had been destroyed late in the previous week, but the explosion was too small to be detected by distant infrasound and seismic networks. A small new dome was extruded following the explosion and was the fifth dome to be observed in this eruptive episode which began in July 2011. During 4-5 May two small explosions were detected. No ash was observed with the mostly-cloudy conditions. Satellite observations were obscured by clouds during 6-8 May.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| 19.023°N, 98.622°W
| Elevation 5393 m
CENAPRED reported that during 2-3 May activity at Popocatépetl increased significantly. Spasmodic tremor was detected along with a dense and continuous plume of gas and ash that drifted W, NW, and NNE. Ash fell in multiple areas, including Amecameca (20 km NW), Atlautla, Ozumba (18 km W), Ecatzingo (15 km SW), Chalco (35 km NW), and some parts of SE México City (70 km NW). On 3 May gas-and-ash plumes rose 1.5 km above the crater and drifted W and NE. Incandescent fragments ejected from the crater landed on the flanks as far as 800 m away. Explosion-generated gas-and-ash plumes the next day rose 2.5 km above the crater and drifted NW. Spasmodic tremor was detected along with a dense and continuous plume of gas and ash that drifted WNW. Later that day gas-and-ash plumes rose 1 km. During 5-6 May gas-and-ash plumes rose 1.5 km above the crater and drifted N, NE, and E. Light ashfall was reported in Atlixco (25 km SE), San Juan Tianguismanalco (22 km SE), Tochimilco (16 km SSE), San Pedro Benito Juárez (10 km SE), and San Nicolás de los Ranchos (16 km ENE). During 5-7 May incandescent fragments ejected from the crater landed on the flanks as far as 500 m away. A gas-and-ash plume drifted ESE on 7 May. The next day activity remained high; seismic events were accompanied by dense and continuous plumes of steam, gas, and ash that drifted mainly ESE. The Alert Level remained at Yellow Phase Three.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
| Eastern Java (Indonesia)
| 8.108°S, 112.922°E
| Elevation 3657 m
CVGHM reported that during 1-29 February multiple pyroclastic flows from Semeru traveled 500 and 2,500 m into the Besuk Kembar and Besuk Kobokan rivers (on the S flank), respectively. During 1 February-30 April dense gray-to-white plumes rose 100-500 m above Jongring Seloko crater and drifted W and N. Incandescence was visible up to 50 m above the crater during 1 February-31 March. Seismicity decreased from March to April. Observations indicated that the lava dome grew in April. On 2 May CVGHM lowered the Alert Level to 2 (on a scale of 1-4) and reminded the public not to approach the crater within a 4-km radius.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| New Britain (Papua New Guinea)
| 5.576°S, 150.516°E
| Elevation 724 m
Based on analyses of satellite imagery, the Darwin VAAC reported that ash-and-steam plumes from Pago rose to an altitude of 13.7 km (45,000 ft) a.s.l. and drifted 75 km NE on 3 May.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
JMA reported that during 1-7 May explosive eruptions from Sakura-jima's Showa Crater occurred 17 times and ejected tephra as far as 1.3 km from the crater. Very small eruptions from Minami-dake Crater occurred on 3 and 5 May. Based on information from JMA, the Tokyo VAAC reported that during 3-4 and 6-8 May explosions produced plumes that rose to altitudes of 1.5-3.7 km (5,000-12,000 ft) a.s.l. and drifted S, SE, and E. Ash was observed in satellite imagery on 3 May. A pilot observed an ash plume on 7 May that rose to an altitude of 2.4 (8,000 ft) a.s.l. and drifted SE.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Japan Meteorological Agency (JMA)
| Halmahera (Indonesia)
| 1.693°N, 127.894°E
| Elevation 1229 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 8-9 May ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 75 km SE.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
KVERT reported that moderate seismic activity from Karymsky continued to be detected during 27 April-4 May, and indicated that possible ash plumes rose to an altitude of 2.3 km (7,600 ft) a.s.l. during 26-27 April and 2 May. Satellite imagery showed a gas-and-steam plume drifting 65 km SE on 27 April; a thermal anomaly was present during 27, 29, and 30 April and 2-3 May. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 2-8 May HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Frequent measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash, and occasionally fresh spatter from an active source at the SE edge of the lava lake, onto nearby areas. Incandescence was visible from both a lava pond in a small pit on the E edge and a small spatter cone on the SE edge of the Pu'u 'O'o crater floor. Geologists observed slowly advancing lava flows on 4 May that were about 1.1 km from the coast, not reaching as far as previous flows on the coastal plain over the past month. On 5 May further collapse of the pit on the E edge of the Pu'u 'O'o crater floor led to much brighter incandescence from that area. Lava flows on the coastal plain stalled while new lava flows high on the pali formed on 5 May, vigorously advancing from the base of the pali to more than halfway across the flow field during 5-8 May.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Nevado del Ruiz
| 4.892°N, 75.324°W
| Elevation 5279 m
According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that during 1-2 May both satellite images and field observers indicated that steam and sulfur dioxide emissions rose from Nevado del Ruiz. Seismicity continued to decrease. On 3 May the Alert Level was lowered to III (Yellow; "changes in the behavior of volcanic activity").
Source: Servicio Geológico Colombiano (SGC)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
KVERT reported that explosive activity at Shiveluch continued during 27 April-4 May. Ground-based observers and satellite imagery indicated that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption and was accompanied by fumarolic activity. Seismic data and visual observations showed that ash plumes rose to altitudes of 4 and 5.4 km (13,200 and 17,800 ft) a.s.l. on 26 April and 1 May, respectively. Satellite imagery showed a weak thermal anomaly on the lava dome during 28-29 April and on 1 and 3 May. Explosions on 1 May produced ash plumes that rose to an altitude of 5 km (16,400 ft) a.s.l.; an ash cloud was observed in satellite imagery drifting 270 km NE that same day.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that the cloud cover which often obscures views of the Soufrière Hills lava dome cleared for a short period on 5 May, revealing multiple areas of incandescence, the same ones first observed on 11 November 2011. Some of the areas were visible to the naked eye while more were visible in a long-exposure photograph. Many of the bright areas were related to fumaroles. The Hazard Level remained at 2 (on a scale of 1-5).
Source: Montserrat Volcano Observatory (MVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
IG reported that during 2-8 May visual observations of Tungurahua were often limited due to cloud cover. Explosions were heard in Baños on 2 May and ashfall was reported in Pillate (7 km W) the next day. On 4 May steam emissions rose from the crater and an ash plume drifted W. Ashfall was reported in Pillate and Choglontus (SW). On 6 May explosions were detected and roaring was heard. An ash plume rose 1.5 km above the crater and drifted WSW. Ashfall covered houses and pastures in Bilbao (8 km W) and Pillate. Ash also fell in Chacauco. An ash plume drifted W on 7 May; ashfall was reported in Bilbao, Pillate, Mapayacu (SW), Cevallos (23 km NW), Pillate (7 km W), and Chacauco.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Criteria & Disclaimers
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.
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