Activity for the week of 21 February-27 February 2001
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
The ash cloud produced from the 19 February eruption of Cleveland volcano was visible on GOES-10 imagery through 1700 on 21 February. The AVO reported that a thermal anomaly was detected on satellite imagery during 21-26 February. On 22 February a pilot reported that steam was observed rising from near the SE shoreline of the volcano where an apparently fresh deposit entered the sea. The deposit may have been an active lava flow fan or hot debris, and was probably the source of the satellite thermal anomaly. On 23 February an active lava flow or hot lahar was observed on the volcano's SW flank. Avalanches of hot, rubbly debris from this flow reached the sea and produced steam clouds at the shoreline.
Sources: US Geological Survey Alaska Volcano Observatory (AVO), Anchorage Volcanic Ash Advisory Center (VAAC)
| 19.514°N, 103.62°W
| Elevation 3850 m
The Volcanological Observatory of Colima University reported that a moderate explosion occurred at 0532 on 22 February. After reviewing video footage of the eruption, the observatory concluded that the ash cloud produced from the eruption rose ~2 km above the volcano at an average velocity of 200 meters/second (m/s). Incandescent ballistics were hurled up to 3 km away from the volcano at a rate of ~100 m/s and landed on the NE and SW flanks of the volcano, and to a lesser extent on the N flank. Large blocks, up to several meters in diameter, rolled ~400 m from the volcano's summit. The collapse of the eruptive column generated small pyroclastic flows that traveled towards the SW. Small amounts of ash fell in the towns of San Marco ~14 km SE of the volcano and Tonila ~13 km to the SSE. According to the observatory, the events were not sufficient to trigger an expansion of the zone of exclusion around the volcano, which remained at 6.5 km.
Source: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima
| Eastern Java (Indonesia)
| 7.93°S, 112.308°E
| Elevation 1731 m
In the wake of earlier concern about renewed volcanic activity at Kelut, the VSI reported that during 12-17 February the temperature of Kelut's crater lake decreased and its pH increased. The temperature decreased to 47.5°C from a range of 50.1 °C to 51 °C, measured during 29 January to 7 February. The pH of the water increased to 5.3 from 5, measured on 7 February. The volcano remained at Alert Level 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| Sulawesi (Indonesia)
| 1.358°N, 124.792°E
| Elevation 1580 m
Visual observations by VSI personnel during 12-17 February revealed that volcanic activity remained low at Lokon, with steam plumes rising 200-350 m above the crater rim. Seismic data were not available because the seismograph on the volcano was broken. The volcano remained at Alert Level 3 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| Luzon (Philippines)
| 13.257°N, 123.685°E
| Elevation 2462 m
PHIVOLCS reported that during the week the number of earthquakes recorded at Mayon was similar to the previous week, and lower SO2 emission rates were recorded. Between 6 and 30 low-frequency volcanic earthquakes were recorded daily during 21-26 February. SO2 emission rates decreased from a maximum value of ~3,000 metric tons per day (t/d) on 20 February, to 1,700 t/d on 21 February. The minimum value was ~1,000 t/d on 24 February. During the week there was an inflationary trend at Mayon's edifice and no incandescence was observed at the volcano's crater. Weak-to-moderate steaming was occasionally observed. Mayon remained at Alert Level 3 (on a scale of 0-5).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
Based on reports from the VSI, the Darwin VAAC stated that during 15-21 February volcanic activity decreased at Merapi. According to the Meteorological and Geophysical Agency of Indonesia, during 11-18 February daily ash emissions rose up to ~150 m above the summit. The volcano remained at Alert Level 4, the highest level.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 14.382°N, 90.601°W
| Elevation 2569 m
The agency responsible for monitoring active volcanoes in Guatemala, INSIVUMEH, observed several indications of renewed eruptive vigor at Pacaya. A local seismometer recorded over 700 earthquakes per day in comparison to 100 earthquakes per day recorded approximately 2 weeks earlier. SO2 gas emissions increased from 253 tons/day to 550 tons/day. In addition, lava was visible in the summit region at MacKenny Crater.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| North Island (New Zealand)
| 39.28°S, 175.57°E
| Elevation 2797 m
The IGNS reported that an episode of strong volcanic tremor was recorded at Ruapehu. The tremor episode peaked on 16 February and was the strongest tremor recorded since the 1996 eruptions, but direct observations of the crater revealed a lack of unusual activity. By approximately 23 February the tremor had declined to background levels. The volcano remained at Alert Level 1.
| North Island (New Zealand)
| 37.52°S, 177.18°E
| Elevation 294 m
Based on reports from White Island tour operators, the IGNS stated that on 19 February minor ash eruptions began at White Island. A light gray plume of fine ash rose ~2 km above the MH vent and drifted towards the mainland. Fine ash was deposited on and near White Island, but only an acid aerosol cloud reached the mainland near the town of Matata. IGNS personnel concluded that the ash eruptions on the 19th were similar to recent eruptive activity at the volcano, therefore White Island remained at Alert Level 1.
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3320 m
According to the Italy's Volcanoes website, on 20 February slow lava extrusion continued from a vent on the NNE flank of the Southeast Crater cone. Mild eruptive activity continued from the Bocca Nuova Crater, with Strombolian bursts from two vents on the NW and E parts of the crater. During 18-20 February, a slight increase in activity was observed at the Bocca Nuova Crater.
Source: Italy's Volcanoes
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Lava continued to flow SE down the Pulama pali and across the coastal plain to within 1 km of the coast. At 1317 on 20 February a M 3.7 earthquake occurred that was centered about 5 km SE of Halemaumau Crater at a very shallow depth. Brief summit deflation occurred on 24 February, but ended the next day with no corresponding period of inflation following it. NE of Kilauea at Mauna Kea volcano, a swarm of earthquakes occurred during 22-24 February on Mauna Kea's NE flank. The earthquakes were all approximately M 3 and occurred at 2-12 km depth. Swarms occasionally occur in this area of Mauna Kea.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 19.023°N, 98.622°W
| Elevation 5393 m
CENAPRED reported that small exhalations occurred at Popocatépetl during the week. The Washington VAAC did not report that ash was visible in satellite imagery. The volcano remained at Alert Level Yellow Phase III, with a restricted area of 12-km-radius.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
The KVERT reported that during 19-20 February there was an increase in seismic activity. Two- and four-minute-long series of shallow earthquakes were registered, possibly corresponding to weak ash-and-gas explosions. On 22 February, a gas-and-steam plume rose 900 m above the volcano. The Concern Color Code remained at Yellow.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
The MVO reported that during 16 to 23 February activity at the Soufrière Hills volcano was similar to the previous week, as lava dome growth continued. The level of seismic activity was also comparable to last week. A large stubby spine was visible in the S part of the summit area on 22 February. The top of the spine was measured as 1,068 m a.s.l. and the main summit area was about 1,030 m a.s.l. New pyroclastic-flow deposits were emplaced towards the E, down Tar River as far as the old coastline, and to the S in the White River Valley as far as 50 m short of the coast on the new pyroclastic delta. Many rockfalls descended the NE flank of the dome into the upper reaches of Tuitt's Ghaut. The Washington VAAC reported that throughout the week low-level ash clouds (up to ~3.4 km a.s.l.), presumably produced by rockfalls, and periodic hot-spot activity were visible on GOES-8 imagery.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
The IG reported that at 1056 on 21 February an eruption sent an ash cloud to ~8.8 km a.s.l. that drifted to the NW. The ash cloud was not visible on the Washington VAAC's GOES-8 imagery. The IG reminded residents near the volcano that strong rains in the area may remobilize ash and generate lahars.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington 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.
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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