Activity for the week of 2 August-8 August 2006
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
| Siau Island (Indonesia)
| 2.781°N, 125.407°E
| Elevation 1797 m
On 2 August, the Alert Level at Karangetang was raised to 4, the highest level. During 1-5 August, white plumes reached heights of 50-300 m (164-984 ft) above the summit (6,000-6,800 ft a.s.l.). Lava flows advanced hundreds of meters to over a kilometer E toward the Batu Awang river and S towards the Keting river during the reporting period. Incandescent rockfalls originating from the summit and ends of the lava flows traveled hundreds of meters E toward the Kahetang and Batu Awang rivers and S towards the Keting and Batang rivers. On 5 August, the Alert level was lowered to 3.
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 2-8 August, lava from Mayon continued to flow mainly SSE along the Mabinit channel and subsequently over a broad sector of the upper and middle SE slopes. During 17 July-3 August, the volume of lava discharged amounted to 17 million cubic meters. Voluminous steaming accompanied lava extrusion. On 4 August, lava flows extended 30 m beyond the 6-km-radius region designated as the Permanent Danger Zone. Areas SE and E experienced light ash fall on 4 August generated by the collapse of deposits. On 6 August, lava flows spilled into the Bonga Valley, E of the Mabinit Chanel.
The Tokyo VAAC reported an eruption cloud at 2331 that reached an altitude of 3.4 km (11,000 ft) a.s.l. and drifted E. On 7 August, the Alert Level was raised to 4 (scale is 0-5, 0 referring to No Alert status) and the Extended Danger Zone (8 km from the summit) was defined. Three explosions (out of nine in a 24-hour period) at 2236, 2246, and 2249 produced incandescent ejections of lava fragments, ash, gas, and steam. According to news reports, ~40,000 people were evacuated from inside the Extended Danger Zone to 20 evacuation centers on 7 and 8 August.
Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC), Associated Press
| 1.467°S, 78.442°W
| Elevation 5023 m
According to the Instituto Geofísico, on 1 August a pyroclastic flow from Tungurahua that traveled an unstated distance W left deposits an estimated 50 m thick consisting largely of blocks and ash. On 2 August, a small lahar that traveled NW caused the closing of a highway. Strombolian activity was observed at night on 3 August. Small explosions were registered during 3-7 August. On 6 August, light ash fall was reported ~8 km SW in the town of Manzano.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
Based on information from JMA, the Tokyo VAAC reported that an explosion at Sakura-jima on 2 August generated a plume that rose to ~2.4 km (8,000 ft) a.s.l. and drifted SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
Activity at Karymsky continued during 29 July-4 August, with 100-300 shallow earthquakes occurring daily. Based on interpretations of seismic data, ash plumes reached altitudes of 3.1 km (10,200 ft) a.s.l. According to the Tokyo VAAC, the Kamchatkan Experimental and Methodical Seismological Department (KEMSD) reported that on 4 August ash plumes reached altitudes of 3.7 km (12,000 ft) a.s.l. A thermal anomaly in the crater was observed. Karymsky remained at Concern Color Code Orange.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
A 4-hectare (10-acre) area of the lava delta at Kilauea's East Lae'apuki collapsed into the ocean on 30 July. The collapse represented less than 15% of the delta's total area.
During 2-8 August, lava from the PKK lava tube flowed into the ocean at two entries on the SE flank, East Lae`apuki and about 3.5 km E at East Ka`ili`ili. Tilt at the Pu`u `O`o cone displayed a saw tooth pattern and tremor remained at a moderate level.
Sources: US Geological Survey Hawaiian Volcano Observatory (HVO), The Honolulu Advertiser
| Papua New Guinea
| 4.08°S, 145.037°E
| Elevation 1807 m
On 4 and 5 August, an ash plume from Manam was visible on satellite imagery at an unknown altitude and extended 30 km NW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
Based on pilot reports, the Darwin VAAC reported that eruption plumes from Merapi on 2 and 3 August reached altitudes of ~6.1 km (~20,000 ft) a.s.l. and drifted W. According to CVGHM, during 2-4 August rockfalls traveled 1 km SE toward the Gendol river and gas plumes reached a maximum of 400 m above the summit (10,900 ft a.s.l.). On 3 August, the Alert Level was lowered to 2 (on a scale of 1-4).
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)
| 19.023°N, 98.622°W
| Elevation 5393 m
According to the Washington VAAC, the Meteorological Watch Office reported emissions from Popocatépetl on 3 August. Ash was not visible on satellite imagery. A bright glow was visible with the camera operated by CENEPRED.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| Eastern Java (Indonesia)
| 8.108°S, 112.922°E
| Elevation 3657 m
Eruption plumes from Semeru were visible on satellite imagery on 2 August. They reached a maximum altitude of 5.2 km (17,000 ft) a.s.l.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 16.72°N, 62.18°W
| Elevation 915 m
During 29 July-4 August, the Soufrière Hills lava dome continued to grow, mainly to the E. The loss of prominent spines made the dome appear more symmetrical. On 2 August, a small pyroclastic flow occurred and was associated with light ash fall to the N of the island. The Alert Level remained at 3 (on a scale of 0-5).
Source: Montserrat Volcano Observatory (MVO)
| United States
| 46.2°N, 122.18°W
| Elevation 2549 m
During 2-8 August, the lava dome at Mount St. Helens continued to grow and produce small rockfalls. On 5 August, two earthquakes (the largest, M 3.6) triggered rockfalls. Resulting dust plumes rose well above the crater rim. The hazard status remained at Volcano Advisory (Alert Level 2); aviation color code Orange.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
| 16.355°S, 70.903°W
| Elevation 5672 m
According to the Buenos Aires VAAC, during 1-8 August pilots reported that ash plumes emitted from Ubinas reached altitudes of between 4.6 km to 6.7 km (15,000 ft-22,000 ft) a.s.l. and drifted generally NE and SW. Ash was visible on satellite imagery on 4 and 6 August.
Source: Buenos Aires 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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