Activity for the week of 9 May-15 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
| 77.53°S, 167.17°E
| Elevation 3794 m
Geologic Summary. Mount Erebus, the world's southernmost historically active volcano, overlooks the McMurdo research station on Ross Island. The 3,794-m-high Erebus is the largest of three major volcanoes forming the crudely triangular Ross Island. The summit of Mount Erebus has been modified by several generations of caldera formation. A summit plateau at about 3,200 m altitude marks the rim of the youngest caldera, within which the modern cone was constructed. An elliptical 500 x 600 m wide, 110-m-deep crater truncates the summit and contains an active lava lake within a 250-m-wide, 100-m-deep inner crater. The glacier-covered volcano was erupting when first sighted by Captain James Ross in 1841. Continuous lava-lake activity has been documented since 1972, punctuated by occasional Strombolian explosions that eject bombs onto the crater rim.
Source: Mount Erebus Volcano Observatory
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3320 m
The Italy's Volcanoes website reported that after more than 8 months of minor activity (slow lava flows, degassing, light ash emission, and low-level Strombolian activity), a new episode of vigorous volcanic activity began at Southeast Crater on 9 May. On 6 May active lava flows and explosions were observed launching pyroclasts and lithics onto the volcano's S flank every 7-10 seconds. On 9 May an obvious increase in activity occurred, with Strombolian bursts occurring every few seconds. By 1745 activity further increased and lava fountains rose up to 100 m above the NNE flank fissure while a dense eruption cloud simultaneously rose above the summit vent. Local press sources reported that air traffic was rerouted during the activity. The high level of activity continued at Southeast Crater through at least 14 May and strong degassing occurred at Bocca Nuova crater.
Sources: Italy's Volcanoes, Etna Volcan Sicilien (Charles Rivière)
| Luzon (Philippines)
| 13.257°N, 123.685°E
| Elevation 2462 m
Volcanic activity increased at Mayon, with a lava dome collapse occurring on 13 May. On 12 May seismographs detected a series of explosions at Mayon's summit crater. The following day the SE-facing portion of the lava dome partially collapsed, leaving a V-shaped opening in the dome. The collapse produced small lava avalanches that reached a maximum runout distance of 300 m down the Bonga Gully. After the collapse, incandescence was observed at the dome and lava fragments fell into the gully. Seismic activity indicated frequent earthquakes, tremor, and explosions. On 14 May rockfalls dominated the seismicity. On 15 May there was a lull in activity, with no rockfalls or lava avalanches occurring. Alert Level 3 remained in effect, prohibiting entry within the 6-km-radius permanent danger zone. PHIVOLCS warned that lava flows and/or pyroclastic flows could be produced in the future and residents just outside of the permanent danger zone should be prepared to evacuate at any time.
Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Associated Press, Agence France-Presse (AFP)
| Fox Islands (USA)
| 53.43°N, 168.13°W
| Elevation 1073 m
During ~0800 to at least 1700 on 11 May AVO detected a small earthquake swarm that was centered near Okmok. Earthquakes in the swarm had magnitudes of approximately 2-3.6, but their locations could not be pinpointed because Okmok is not monitored by a local seismic network. AVO noted that the earthquakes may have been of volcanic origin, but earthquake swarms with similar sizes and character are not uncommon at Aleutian arc volcanoes and do not necessarily lead to eruptive activity.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Ryukyu Islands (Japan)
| 29.638°N, 129.714°E
| Elevation 796 m
Beginning on the morning of 9 May volcanic activity increased at Suwanose-jima when a tremor event commenced. The tremor increased at 1100 and became more violent at 2100. Around noon on 11 May an eruption produced an ash cloud that rose 1-1.5 km above the crater. The Suwanose-jima Branch of Toshima village, ~4 km NNW of the active Otake crater, reported that abundant ash fall was observed in the village on 11 May. Vigorous eruptions on the evening of 12 May and the morning of 13 May deposited up to 3 cm of ash in the village. At 0900 on 14 May the eruption seemed to have stopped. The Sakurajima Volcano Observatory reported that plumes associated with volcanic tremor events have been observed at Suwanose-jima since the new crater was formed during the December 2000 eruption.
Sources: Volcano Research Center-Earthquake Research Institute (University of Tokyo), Tokyo Volcanic Ash Advisory Center (VAAC)
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
Cleveland was obscured by clouds during most of the week and no thermal anomalies were observed. AVO had received no reports of significant volcanic activity from pilots, residents, or satellite remote-sensors since the last eruption on 19 March.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Surface lava flows were visible traveling down Pulama Pali. Three ocean-entry benches were seen along the SE corner of the active lava flow field. The active lava flow was 300-500 m from the nearest house in the Royal Gardens subdivision, but the homes may be protected from the lava by a barrier of `a`a deposited in 1983. Volcanic tremor was higher than normal during 12 and 13 May and small earthquakes were recorded in the caldera. Tiltmeters in the summit area and along the east rift zone indicated no significant deformation.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 19.023°N, 98.622°W
| Elevation 5393 m
CENAPRED reported that at 2301 on 13 May a small explosion sent incandescent fragments as far away as 0.5 km from the crater. At 0939 on 14 May an ash-and-steam plume rose 1.5 km above the crater.
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
After a pyroclastic-flow producing eruption occurred at ~0958 on 7 May, seismic activity decreased but it remained above background levels for most of the week, a new extrusive dome formed, and the Concern Color Code was reduced. A noticeable increase in seismic activity occurred between 1820 and 1852 on 7 May, and may have corresponded to an explosion that produced an ash-and-gas plume. The plume was visible in satellite imagery rising up to 4 km a.s.l. and drifting ~40 km to the WNW. A small amount of ash fell in the town of Kliuchi, 46 km from the volcano. During 11-15 May seismic activity continued to decrease, but remained above background levels. Many small earthquakes occurred at the volcano's edifice. At 0900 on 12 May a new extrusive lava dome was observed from Kliuchi that was steaming intensely, 100 m high, 200 m wide at the upper part of the dome, and had a volume of ~10 million m3. Observers in Kliuchi reported that by 2140 on 13 May the dome had grown ~50 m higher. Weak explosions produced ash-and-steam plumes that rose up to 1 km above the new dome. On 16 May the Concern Color Code at Shiveluch was reduced from Orange to Yellow.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that during 4-11 May volcanic activity increased slightly, with more rockfalls and seismic activity recorded than the previous week and a small pyroclastic flow on 9 May. The pyroclastic flow traveled ~2.5 km S of the dome down the White River. There still appeared to be a very small amount of growth in the S side of the lava dome, and observation flights confirmed that most rockfall activity occurred in the dome's S sector. Sulfur dioxide flux remained low.
Source: Montserrat Volcano Observatory (MVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
Heavy rainfall in the vicinity of Tungurahua caused the remobilization of ash deposited on the upper flanks of the volcano, producing several lahars. Lahars traveled down the Cusúa, Basural, Mandur, ún, and Ulba gorges. Lahars caused the closing of the Baños-Riobamba highway and blocked a route to the town of Baños.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
News Feeds and Google Placemarks
The RSS (Really Simple Syndication) 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.
The CAP (Common Alerting Protocol) feeds are XML files specifically formatted for disaster management. They are similar in content to the RSS feed, but contain no active links.
A Google Earth network link for the Weekly Volcanic Activity Report 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.
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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RSS and CAP Feeds
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.
CAP (Common Alerting Protocol) feeds are XML files specifically formatted for disaster management.
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.