Activity for the week of 17 May-23 May 2006
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
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
On 23 May, AVO reported that an astronaut aboard the International Space Station observed an ash plume from Cleveland at 1500. A plume was visible on satellite imagery at 1507 that drifted SW and reached a height of 6.1 km (20,000 ft) a.s.l. At 1700, an image showed the detached ash plume 130 km SW of Cleveland. The Concern Color Code was raised to Yellow. No precursory or current seismic information is available because Cleveland does not have a real-time seismic network.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
The Alert Level at Merapi remained at 4, the highest level, during 17-22 May. Incandescence and sulfur-dioxide plumes were observed. Pyroclastic flows to the SW and SE reached 4 km on 19 May and 3 km on 20 May. On 22 May, the lava dome volume was estimated at ~ 2.3 million cubic meters. The Darwin VAAC reported that low-level emissions continued during 18-19 and 23 May. CVGHM recommended that residents who live in valleys on the NNW flanks near Sat, Lamat, Senowo, Trising, and Apu Rivers and on the SE flank near Woro River be allowed to return to their homes. Residents remained evacuated from villages within a 7 km radius from the volcano's summit and within 300 m of the banks of the Krasak/Bebeng, Bedog, and Boyong Rivers to the SW, and the Gendol River to the SE.
According to news reports, an eruption producing a cloud of hot gas and ash was witnessed on 17 May. Witnesses said the size of the plume was smaller than ash-and-gas plumes on 15 May. On 18 May, a representative for Merapi from the Center for Volcanological Research and Technology Development (part of CVGHM), reported new ashfall.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC), Associated Press, Agence France-Presse (AFP), Reuters
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that on the morning of 20 May a major lava-dome collapse at Soufriére Hills occurred over a time period of less than three hours. Approximately 90 million cubic meters of the lava dome material was shed from the summit leaving a broad, deep, eastward-sloping crater. Pyroclastic flows traveled E down the Tar River Valley and were estimated to extend out to 3 km over the sea. Lahars due to excessive rain were produced NW in the Belham River Valley, N in the Trants area, and to the NE. An ash cloud reached 16.8 km (55,000 ft) a.s.l. by 0740, the highest reported ash cloud during the 10 years of the eruption, and traveled NW. Lithics (average size of 3.5 cm across) fell NW of the volcano. On 21 May, ash and mud fell on the northern parts of the island. Prior to the lava-dome collapse, during 12 May and 19 May, lava extrusion had continued.
The Washington VAAC reported that the ash plume from the 20 May dome collapse initiated at approximately 0700. On 21 May, the remnant ash cloud from 20 May was at a height of ~11.3 km (37,000 ft) a.s.l. along the northern coast of South America and the Southern Caribbean. An ash cloud at a height of ~7 km (23,000 ft) a.s.l. extended S of Puerto Rico and the Dominican Republic. According to news reports, the ash cloud on 20 May forced the suspension of some international flights in areas of the Caribbean through 21 May. On 22 May, multi-spectral imagery indicated that an ash plume at a height of ~3 km (10,000 ft) a.s.l. extended over the islands of Anguilla, St. Martin, and St. Kitts. On 23 May, a thin ash plume was visible on satellite imagery and moved WNW.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC), Associated Press
| 14.473°N, 90.88°W
| Elevation 3763 m
On 17 May, INSIVUMEH reported that fumarolic emissions reached ~600 m above the volcano (14,300 ft a.s.l.). and drifted E and W. Active lava flows reached ~100 m SW toward the Taniluyá River and ~500 m SW toward the Ceniza River. Avalanches occurred from lava-flow fronts. The Washington VAAC reported a short low-level plume on 18 May that drifted N from the volcano.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)
| 1.22°N, 77.37°W
| Elevation 4276 m
INGEOMINAS reported that during 15-22 May, a partially solidified lava dome remained in the main crater of Galeras. Seismicity and the sulfur-dioxide flux continued at very low levels. Galeras remained at Alert Level 2 (likely eruption in days or weeks).
Source: Servicio Geológico Colombiano (SGC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
During 12-19 May, eruptive activity continued at Karymsky. Based on interpretations of seismic and satellite data, ash plumes rose to a height of 8 km (26,200 ft) a.s.l. Ash plumes extended for about 50 km to the S and NE. KVERT warned that activity from the volcano could affect nearby low-flying aircraft. Karymsky remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Eastern Java (Indonesia)
| 7.93°S, 112.308°E
| Elevation 1731 m
Based on a pilot report, the Darwin VAAC reported that on 18 May an ash plume from Kelut reached a height of 5.5 km (18,000 ft) a.s.l. The report was not verified by ground observations. [Correction: VAAC report did not mention ash in the plume]
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Small lava flows were visible on 19 May and minor incandescence was observed on 21-22 May at Kilauea's East Lae`apuki lava delta. Seismicity levels were low at the summit and moderate at Pu`u `O`o. After 16 May, there was very little change in deformation.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 16.507°S, 168.346°E
| Elevation 1413 m
According to Vanuatu's National Disaster Management Office, Lopevi volcano remains at Alert Level 2. An official spokesperson reported no new ashfall during 17-22 May. The last report of an ash plume was on 15 May.
Source: Shanghai Daily
| United States
| 46.2°N, 122.18°W
| Elevation 2549 m
During 17-22 May, the lava spine continued to grow inside the crater of Mt. St. Helens producing minor rockfalls and moderately-sized rock avalanches that generated small ash plumes. On 17 May, lava extrusion continued to deform the W part of the lava dome and night-time incandescence from rockfalls was observed.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
During 17-20 May, ash emissions from Tungurahua increased. On 18 May, an ash plume reached a height of 5.2 km (17,000 ft) a.s.l. and extended NW, according to Washington VAAC reports. The Washington VAAC also noted that on 19 May, the Instituto Geofísico observed an ash plume that reached a height of 12 km (40,000 ft) a.s.l. On satellite imagery, ash plumes were visible on 20 and 23 May and extended SW. Hotspots were visible on satellite imagery 19-20 and 23 May. The ash plume and incandescence on 23 May were also observed by Instituto Geofísico staff.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC), Reuters
| 16.355°S, 70.903°W
| Elevation 5672 m
Based on information from significant meteorological advisories (SIGMET) and pilot reports, the Buenos Aires VAAC reported that ash emitted from Ubinas during 20-23 May rose to a maximum height of 7.3 km (24,000 ft) a.s.l.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)
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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