Activity for the week of 23 May-29 May 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
| 11.984°N, 86.161°W
| Elevation 635 m
The Washington VAAC reported that Masaya may have erupted on 23 May at ~1300. Ground observations from the capital city of Managua, 20 km NW of the volcano, indicated that there was a reduction in visibility to the SE of the city due to volcanic "smoke" and steam. The presence of the ash cloud could not be confirmed on satellite imagery due to thunderstorms in the area.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
Neither eruptive activity nor thermal anomalies have been observed at Cleveland during the previous 6 weeks.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3295 m
According to the Italy's Volcanoes website, through 25 May at Southeast Crater lava continued to flow from a small cone on its NNE flank and mild Strombolian activity continued at its summit vent. Volcanic activity had been relatively regular since a strong eruptive episode began on 9 May.
Source: Italy's Volcanoes
| 0.171°S, 78.598°W
| Elevation 4784 m
Based on information from the IG, the Washington VAAC reported that on 25 May at 1110 a steam-and-ash emission from Guagua Pichincha's summit rose up to ~8.5 km a.s.l. The cloud was not visible on satellite imagery.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
The tilt event that began on 20 May ended the following day and HVO reported that the precursory deflation, remarkably rapid inflation of 10-11 microradians in one hour, and then the slow relaxation of the summit presumably recorded a pulse of magma supplied to the summit reservoir complex. The pulse was then transferred to the Pu`u `O`o area where it is currently stored. Lava continued to flow into the ocean at the SE corner of the lava flow field. On 23 May surface lava flows were visible. On 26 May tremor occurred at low-to-moderate levels beneath Pu`u `O`o, earthquake swarms occurred beneath Kilauea caldera, and background tremor was low. Tiltmeters in the summit area and along the east rift zone indicated no significant deformation.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| Luzon (Philippines)
| 13.257°N, 123.685°E
| Elevation 2462 m
During the week seismic activity was relatively low at Mayon and was associated with occasional rockfalls that descended to the SE down the Bonga Gully. In addition, moderate steaming occurred, incandescence was occasionally observed at the crater, and SO2 emission (up to 5,700 metric tons/day) was above the baseline value of 500 tons/day. On 28 May at 1036 the seismic network recorded a low-frequency volcanic earthquake that was inferred from seismic data to be associated with an ash puff. The ash puff not visible due to meteorological cloud cover. Alert Level 3 remained in effect, prohibiting entry within the 6-km-radius permanent danger zone. PHIVOLCS warned that residents around the volcano, especially those staying in areas facing the Bonga Gully and the SE sector, should be vigilant and prepared to evacuate at any time.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
| 19.023°N, 98.622°W
| Elevation 5393 m
Small-to-moderate sized exhalations occurred during the week. Based on information from the Mexico City MWO, the Washington VAAC reported that an eruption occurred on 26 May at 1122 that sent a steam-and-ash plume up to ~7 km a.s.l.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
On 22 May at 0209 an explosive eruption produced a mushroom-shaped ash column that rose to a height of more than 10 km a.s.l. (preliminary reports stated ~20 km). The high-pressure system over N Kamchatka caused the plume to remain fairly stationary over the region as it spread out to cover an area of ~50,000 km2. Observations from the town of Klyuchi, 46 km from the volcano, revealed that the new lava dome (first observed on 12 May) and the W part of the old dome were destroyed during the eruption. After the 22 May eruption several small eruptions produced ash-and-gas clouds that rose up to 2 km a.s.l. On 23 May a large thermal anomaly was observed at Shiveluch. In satellite imagery the anomaly consisted of ten pixels ranging in temperature from 30 to 49 °C with two pixels near saturation. The anomaly may have represented a pyroclastic flow that originated from the dome area. Seismic activity remained above background levels. On 24 May the Concern Color Code was reduced from Red to Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that during 18-25 May volcanic activity increased in comparison to the previous week. The main increase in activity occurred during 19 to 21 May when many large long-period and hybrid earthquakes were recorded. Low-level convective ash clouds generated during this increase in activity rose less than 2 km a.s.l. Observations confirmed that the main growth area was still concentrated in the S sector of the lava dome. A large volume of new talus had built out above the White River, to the S of the volcano, and on 24 May near-continuous rockfalls and small pyroclastic flows were observed. Sulfur dioxide flux increased, with an average of 700 metric tons per day measured on 21 May, considerably higher than the average flux during previous weeks of 100 to 200 tons per day. Due to the increase in activity the daytime entry zone was closed beginning on 21 May.
Source: Montserrat Volcano Observatory (MVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
Based on information from the IG, the Washington VAAC reported that on 26 May at 2215 ash from an eruption of Tungurahua was observed at a height of ~7 km a.s.l. drifting to the NE. Extensive cloudiness in the area prohibited ash cloud detection on satellite imagery.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
Weekly Reports Archive
||Huila, Nevado del
||Hunga Tonga-Hunga Ha'apai
||Soufriere St. Vincent
||South Sarigan Seamount
||Tair, Jebel at
|Campi Flegrei del Mar di Sicilia
|Chillan, Nevados de
||Palena Volcanic Group
||Kick 'em Jenny
|Dieng Volcanic Complex
||Rincon de la Vieja
|Etorofu-Yakeyama [Grozny Group]
||Lengai, Ol Doinyo
||Ruiz, Nevado del
|Fournaise, Piton de la
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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:
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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.
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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.