Activity for the week of 19 May-25 May 2004
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
Awu
| Sangihe Islands (Indonesia)
| 3.689°N, 125.447°E
| Elevation 1318 m
DVGHM reported a sudden increase in seismicity at Awu beginning on 16 May when 12 volcanic earthquakes were recorded. In addition, tremor was recorded during 1110-1540. Gas plumes rose ~75 m above the crater that were thicker than earlier in the month, but they did not change color or form clumps. On 18 May, six volcanic earthquakes were recorded and tremor continued. The same day DVGHM raised the Alert Level from 1 to 2. According to news reports, on 21 May hundreds of residents of the villages of Manente, Kolongan, Kendahe, and North Tabukan began to flee due to fears of an eruption.
Sources: Agence France-Presse (AFP), Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), The Jakarta Post
Sirung
| Pantar Island (Indonesia)
| 8.508°S, 124.13°E
| Elevation 862 m
According to DVGHM, the news reports of an eruption at Sirung around 13 May were false. There was no activity at the volcano.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Ongoing Activity
Aira
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
Based on information from JMA, during 19-24 May several explosions at Sakura-jima produced ash clouds. The highest reported ash cloud reached ~2.4 km a.s.l. on 24 May.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
Anatahan
| Mariana Islands (USA)
| 16.35°N, 145.67°E
| Elevation 790 m
During 20-25 May, volcanic activity continued at Anatahan. Explosions every few minutes threw volcanic material hundreds of meters out of the crater, and steam-and-ash emissions probably rose several hundred meters above the volcano. On 25 May satellite imagery showed an ash plume extending at least 5 km NW of the volcano.
Source: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program
Dukono
| Halmahera (Indonesia)
| 1.693°N, 127.894°E
| Elevation 1229 m
During 19-25 May, Dukono occasionally emitted ash plumes that were visible on satellite imagery. Plumes rose to heights of ~3 km a.s.l.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Fuego
| Guatemala
| 14.473°N, 90.88°W
| Elevation 3763 m
During 18-21 May, moderate volcanic activity continued at Fuego. Several explosions produced ash plumes, with the highest one reaching ~1.2 km above the volcano on 20 May. On 21 May, avalanches of incandescent volcanic material traveled toward the ravines of Seca (to the W) and Taniluya (to the SW).
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Kilauea
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 19-21 May, the Banana lava flow traveled toward down the Pulama pali toward the sea, reaching within ~200 m of the sea cliff before stopping on the morning of 21 May. Around this time, a few incandescent areas were visible along the flow. During 19-23 May, tremor was at low levels at Kilauea's summit and at moderate levels at Pu`u `O`o. There were small episodes of inflation and deflation at the volcano.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Nyamuragira
| DR Congo
| 1.408°S, 29.2°E
| Elevation 3058 m
The Toulouse VAAC reported that satellite imagery showed a weak eruption of ash at Nyamuragira on 25 May.
Source: Toulouse Volcanic Ash Advisory Centre (VAAC)
Nyiragongo
| DR Congo
| 1.52°S, 29.25°E
| Elevation 3470 m
The Toulouse VAAC reported that satellite imagery showed a weak eruption of Nyiragongo on 21 May. Activity intensified during the evening of 24 May. By the evening of 25 May, the volcano was no longer visible on satellite imagery due to meteorological clouds in the area.
Source: Toulouse Volcanic Ash Advisory Centre (VAAC)
Piton de la Fournaise
| Reunion Island (France)
| 21.244°S, 55.708°E
| Elevation 2632 m
The eruptive episode that began at Piton de la Fournaise on 2 May stopped on 18 May. This followed 2 days of high eruptive activity when numerous pahoehoe lava flows and Pele's hair were produced. Around 1550 on the 18th the amount of eruption tremor decreased, completely stopping at 1615 and signaling the eruption's end.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)
Reventador
| Ecuador
| 0.077°S, 77.656°W
| Elevation 3562 m
Strong rain on 15 May caused several lahars to travel down Reventador's flanks. They persisted through 16 May.
Source: Instituto GeofÃsico-Escuela Politécnica Nacional (IG)
Santa Maria
| Guatemala
| 14.757°N, 91.552°W
| Elevation 3745 m
During 18-21 May, weak-to-moderate explosions at Santa MarÃa's Santiaguito lava-dome complex produced gas-and-ash plumes that rose to ~1 km above the crater. Many of the moderate explosions were accompanied by avalanches of incandescent volcanic material. On 20 May around 1800 a small partial collapse at the edge of the Caliente lava dome produced an avalanche of incandescent volcanic material to the SW that reached the base of the dome.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Semeru
| Eastern Java (Indonesia)
| 8.108°S, 112.922°E
| Elevation 3657 m
The Darwin VAAC reported that a thin ash plume from Semeru was visible on satellite imagery on 23 May around 0625. The plume reached a height of ~4.3 km a.s.l. and extended ~110 km SSE.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Shishaldin
| Fox Islands (USA)
| 54.756°N, 163.97°W
| Elevation 2857 m
During 14-21 May seismic unrest continued at Shishaldin, characterized by weak seismic tremor and small explosions. On 16 May, a pilot reported an ash plume that rose ~300 m above the volcano's summit. Satellite imagery from 17 May showed a vigorous plume emanating from the summit that may have contained small amounts of ash. Shishaldin remained at Concern Color Code Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Soufriere Hills
| Montserrat
| 16.72°N, 62.18°W
| Elevation 915 m
Volcanic and seismic activity at Soufrière Hills during 14-21 May remained at low levels. On 21 May intense rainfall produced large mudflows in the Belham Valley. At the peak of the activity, the entire width of the valley floor at Belham Bridge was flooded and standing waves up to 2 m high were observed. The sulfur-dioxide flux was low for most of the report period.
Source: Montserrat Volcano Observatory (MVO)
Tungurahua
| Ecuador
| 1.467°S, 78.442°W
| Elevation 5023 m
During 19-24 May, small-to-moderate emissions of gas, steam, and ash continued at Tungurahua. The highest rising plume reached ~2.5 km above the volcano on 23 May. On the morning of 19 May a mudflow occurred in the Pampas sector, but it did not affect the highway. Strombolian activity was visible in the crater on the evening of 23 May.
Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
Veniaminof
| United States
| 56.17°N, 159.38°W
| Elevation 2507 m
Unrest continued at Veniaminof during 14-21 May, characterized by intermittent volcanic tremor. The tremor was similar to seismic signals recorded the previous month in association with small ash plumes, suggesting that ash bursts continued. A pilot report on 18 May indicated the presence of an ash plume rising to heights of 300-900 m above the volcano's summit and extending ~32 km NE. Veniaminof remained at Concern Color Code Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
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 monthly, and 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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An RSS (Really Simple Syndication) feed for the Weekly Volcanic Activity Report first made available on 5 March 2008 can be utilized with the aid of various free downloadable readers. The report content of the news feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website. On 12 March 2009, GeoRSS tags were added so that the latitude and longitude for each volcano could be included with the feed.
At the end of each individual report is a list of the sources used. We would like to emphasize that the World Organization of Volcano Observatories (WOVO) website (http://www.wovo.org/) lists the regional volcano observatories that have the most authoritative data for many of these events.
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Google Earth Placemarks
A Google Earth network link for the Weekly Volcanic Activity Report was first made available on 1 April 2009. This file can be loaded into the free Google Earth software, and in turn will load placemarks for volcanoes in the current weekly report. Placemark balloons include the volcano name, report date, report text, sources, and links back to the GVP volcano page for that volcano and to the complete Weekly Report for that week.
