Activity for the week of 9 July-15 July 2003
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
| 16.72°N, 62.18°W
| Elevation 915 m
High levels of pyroclastic-flow activity began at Soufriere Hills on 12 July. A hybrid earthquake swarm that began on 9 July merged at 0700 on 12 July into a continuous tremor signal. Prolonged and heavy rainfall occurred on the 12th during 0600-0900, causing mudflows into the Belham Valley. Pyroclastic flows began to travel into the Tar River Valley, with a moderate-sized flow occurring at 0653. A series of similar-sized pyroclastic flows traveled in the Tar River Valley throughout the morning. The first pyroclastic flow reached the sea at 1045. Pyroclastic-flow activity increased slowly through the afternoon until it became almost continuous. Flows also occurred into Tuitt's and White's ghauts. The activity picked up markedly at 1827, with more energetic pyroclastic flows. The level of activity fluctuated thereafter, with several smaller pyroclastic flows into the Tar River Valley, before escalating again at 2005 with another phase of near-continuous pyroclastic flows. The flows increased in size and several surges traveled 2 km over the sea at the mouth of the Tar River Valley. Pyroclastic flows also reached the sea in White's Ghaut and the Spanish Point area. These flows resulted in heavy ashfall and accretionary lapilli, particularly between Salem and Woodlands. A number of explosive events took place during this collapse, with the largest occurring between 2300 and 2400. The Washington VAAC reported that ash clouds rose to a maximum height of ~15 km a.s.l.
Heavy falls of ash and rock fragments occurred over all of the inhabited parts of Montserrat. The ashfall deposit was 115 mm thick at Lime Kiln Bay. The ash burden resulted in the collapse of several wooden buildings in the Salem area. Vegetation damage was extensive with downed trees and branches broken from many others. Many birds were killed by the ash or trapped alive in it. Ashfall from this event was reported on the islands of Nevis, St Kitts, Anguilla, and St Maarten, and resulted in the closure of several airports. At 0910 on 13 July an explosive eruption occurred, following 2 hours of very low seismic activity. The Washington VAAC estimated a cloud height of ~12 km a.s.l.
During a helicopter reconnaissance flight on the morning of 14 July, a large collapse scar was seen in the lava dome directed down the Tar River Valley. The Tar River Valley was extensively modified and eroded with a deep canyon gouged by the pyroclastic flows. The fan had been extended eastwards into the sea and northwards along the coast. The area north of the Tar River Valley extending to Killyhawk Ghaut was devastated.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC), Associated Press, Reuters
| Mariana Islands (USA)
| 16.35°N, 145.67°E
| Elevation 790 m
As of 11 July, the eruption that began at Anatahan on 10 May continued to wane as shown by decreasing volcanic-tremor amplitudes and observations. On 9 July observations revealed that only white steam was being emitted from East Crater along with a small amount of light-brown fume. During 9-15 July, only faint ash plumes were visible on satellite imagery.
Sources: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program, Washington Volcanic Ash Advisory Center (VAAC)
| Kyushu (Japan)
| 32.884°N, 131.104°E
| Elevation 1592 m
A tremor event with a moderate amplitude was recorded at Aso on 10 July at 1718. Aso weather station personnel inspected the area around Nakadake crater and found a small amount of tephra newly deposited at Hakoishi-Toge about 6 km ENE of the crater. Dr. Yasuaki Sudo of Aso Volcanological Laboratory, Kyoto University, inspected the crater area and determined that a phreatic eruption had occurred. Mud emitted during the eruption reached as far as 10 km from the crater. The color of the crater lake surface changed to dark gray from green, its color on 8 July.
Source: Japan Meteorological Agency (JMA)
| 19.514°N, 103.62°W
| Elevation 3850 m
Based on information from the Mexico City MWO, the Washington VAAC reported that an emission occurred at Colima on 11 July at 2045. Extensive meteorological cloud cover made detecting ash on satellite images difficult. An eruption began on 15 July at about 0914 that produced an ash cloud to a height of ~9.1 km a.s.l. A narrow ash plume was visible on satellite imagery.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| 14.473°N, 90.88°W
| Elevation 3763 m
INSIVUMEH reported to the Washington VAAC that on 9 July at 0530 Fuego's lava dome collapsed, producing pyroclastic flows. After the collapse, strong explosions sent ash to ~2 km above the volcano's summit. Ash clouds drifted W and ash fell in communities W and SE of the summit. An ash cloud was visible on satellite imagery.
Sources: Washington Volcanic Ash Advisory Center (VAAC), Prensa Libre
| 10.412°N, 123.132°E
| Elevation 2435 m
An emission from Canlaon on 10 July at 1735 sent an ash-and-steam cloud to a height of ~1 km above the summit. The cloud was visible from Canlaon City and drifted NW, SW, and NE, depositing ash in an area within a 4 km radius around the crater. Emissions also occurred on 11 July during 0620-0624 and 0658-0705 that rose to ~1.3 km above the crater and drifted SE. Canlaon remained at Alert Level 1, with a 4-km-radius Permanent Danger Zone.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 12-15 July at Kilauea, surface lava flows were occasionally visible on the coastal flat and upslope on the Pulama pali fault scarp and Paliuli. Seismicity continued at moderate levels at Kilauea's summit, with small low-frequency earthquakes persisting at shallow depths at a rate of about 1-2 per minute. Volcanic tremor at Pu`u `O`o remained at moderate-to-high levels, as is the norm recently. Small periods of inflation and deflation occurred during the report week.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| Central Kamchatka (Russia)
| 56.056°N, 160.642°E
| Elevation 4754 m
Seismicity was above background levels at Kliuchevskoi during 4-12 July. Several earthquakes with magnitudes of 1.5-2.2 occurred at depths around 30 km and at shallower levels. The amount of spasmodic tremor decreased by the end of the report week. Ash explosions reached ~1 km above the volcano each day of the report week, except 6 July. On 4 July ash from an explosion reached ~2 km above the volcano. Kliuchevskoi remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Flores Island (Indonesia)
| 8.365°S, 122.833°E
| Elevation 1095 m
Based on a pilot's report, the Darwin VAAC reported that an ash plume was visible above Leroboleng on 14 July at 1606 at a height of`~2.5 km. Ash was not visible on satellite imagery and VSI personnel could not observe the volcano.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 19.023°N, 98.622°W
| Elevation 5393 m
During 9-15 July, moderate emissions of mainly gas, steam, and sometimes ash, occurred at Popocatépetl. An eruption on 9 July at 0910 sent ash to a height of ~1 km above the summit.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
During 9-15 July, volcanic and seismic activity at Tungurahua remained at relatively low levels. IG reported that no immediate changes in activity are expected until there is a new injection of magma into the volcano.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
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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:
- 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.
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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.
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.