Active volcanoes in the world from 03/08/2011 to 09/08/2011 + 2 videos

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 every Week (mostly 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 of 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 or activity change

CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
* AVO reported that observations from 2 August of the lava dome growing in Cleveland's summit crater revealed growth from about 40 m to 50 m in diameter since 29 July. Weak thermal anomalies were observed in satellite imagery during 2-3, 5, and 7-9 August when cloud cover was limited or absent. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.
Volcano information: Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.

ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m
* Sezione di Catania - Osservatorio Etneo reported that the ninth paroxysmal eruptive episode from Etna in 2011 took place at the New SE Crater (located on the E flank of the old SE Crater cone and previously called the "pit crater") during the night of 5-6 August. Weak Strombolian explosions occurred in the crater during the afternoon on 5 August and gradually increased over the next few hours. At 2215 lava flowed over the E rim of the crater and towards the W slope of the Valle del Bove. Strombolian activity rapidly increased and formed a lava fountain that rose 100 m above the crater rim. Activity again intensified and jets of lava rose several hundred meters high. An eruption plume laden with ash and lapilli rose a few kilometers above the crater and drifted SE. At the climax of the eruption lava fountains exceeded 500 m in height. Just after midnight the incandescent jets diminished in height, continued to pulsate for about an hour, then further diminished. By 0215 on 6 August the eruption was substantially over. Ash-and-lapilli fall were observed in the SE sector of the volcano, between Zafferana (10 km SE) and Viagrande (16 km SSE) and between Acitrezza (23 km SE) and Pozzillo (19 km SE) along the Ionian coast.
Volcano information: Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania.

Eruption video August 5-6

image courtesy Smithsonian Institution

KARANGETANG [API SIAU] Siau I 2.78°N, 125.40°E; summit elev. 1784 m
* CVGHM reported that during July and August cloud cover often prevented observations of Karangetang, although white smoke was sometimes observed rising as high as 500 m above the crater. At night incandescence up to 10 m was often observed.
* On 8 July a phreatic eruption occurred from the N part of the Main Crater, ejecting material 150 m high. On 24 July and 1 August incandescent material traveled 1,500 m from the Main Crater. Sounds indicating an eruption were heard on 7 August, although fog prevented observations of the crater. Based on recent visual observations and increased seismicity, the Alert Level was raised to 3 (on a scale of 1-4) on 8 August. According to a news article, about 600 people living on the flanks evacuated.
Volcano information: Karangetang (also known as Api Siau) lies at the northern end of the island of Siau, N of Sulawesi, and contains five summit craters strung along a N-S line. One of Indonesia's most active volcanoes, Karangetang has had more than 40 recorded eruptions since 1675. Twentieth-century eruptions have included frequent explosions, sometimes accompanied by pyroclastic flows and lahars.

KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
* HVO reported that on 3 August at 1402 the floor of Kilauea's Pu'u 'O'o crater, which had risen significantly over the past month, began to subside. At 1420 lava erupted from a vent low on the W flank of the Pu'u 'O'o cone, about halfway between Pu'u 'O'o Crater and the E end of the Kamoamoa fissure, and formed two branches. The weaker flow traveled N into a forested kipuka. The higher-volume S branch quickly advanced down Kilauea's S flank along the edge of flows erupted during 2002-2004. By 1515, the crater floor and perched lava lake began to collapse; the circulation in the lava lake was maintained as the crater floor dropped. Within a few hours the lava lake was no longer visible and the crater floor, which had dropped 75-85 m, was covered with rubble. Between 1530 and 1615, the preliminary sulfur dioxide emission rate from all east rift zone sources was as high as 7,000 tonnes/day. The rate decreased to 4,000 tonnes/day at about 1700. Also by that time the lava flow had advanced 3.6 km.
* During 4-9 August lava continued to flow from multiple W-flank vents topped with spatter cones, ponding in a low area due to a decreasing effusion rate. The Pu'u 'O'o crater rim was extremely unstable; continued collapses along the crater walls sendt blocks of rock onto the crater floor. Lava also slowly flowed back onto the collapsed crater floor.
* During 3-9 August the level of the summit lava lake fluctuated deep in the 150-m-diameter vent inset within the E wall of Halema'uma'u Crater and circulated with various patterns. Overall, the lake level receded and on 6 August was about 75 m below the crater floor. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby.
Volcano information: Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.

Collapsing Crater floor Video (Time Lapse video)

LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
* CVGHM reported that during 24 July-8 August seismicity decreased at Tompaluan crater, in the saddle between the Lokon-Empung peaks, with a drastic reduction on 26 July. During 27 July-8 August white plumes rose 100-400 m above the crater. The Alert Level remained at 3 (on a scale of 1-4). Residents and tourists were not permitted within a 3-km radius of the crater.
Volcano information: The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.

RABAUL New Britain 4.271°S, 152.203°E; summit elev. 688 m
* RVO reported that white vapor plumes rose from Rabaul caldera's Tavurvur cone during 1-3 August. An explosion on 3 August produced a gray ash plume that rose 1 km above the crater and drifted NNW. Sustained emissions of pale-gray ash continued for about an hour afterwards. In addition, ash deposited at the former airport was re-suspended and blown NW into the E part of Rabaul town (3-5 km NW) and towards Namanula hill (3 km W). Seismicity was very low, although two periods of harmonic tremor on 2 August and the explosion and ash emissions on 3 August were detected.
* During 4-5 August gray ash emissions periodically continued, punctuated by a few large and notable explosions. Ash plumes from the explosions rose 1 km above the crater and drifted N and NW producing fine ashfall in the E part of Rabaul town, Namanula Hill, and further downwind towards Tavui Point. Moderate seismicity consisting of low-frequency earthquakes, explosions, and volcanic tremors with variable durations was detected. During 5-9 August activity increased, characterized by an increased frequency and duration of ash emissions and more explosions. About 34 explosions were recorded between 5 and 8 August. Ash-rich clouds that rose 1.5 km above the crater drifted NW causing ashfall in most parts of Rabaul town and in areas between Toliap and Nonga (10 km NW). GPS measurements on Matupit Island continued to show long-term inflation; about 10-11 cm of uplift had been recorded since August 2010.
Volcano information: The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay. Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.

REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m
* The IG reported that scientists conducting an overflight of Reventador on 14 July noted that the lava dome at the top of the 2008 cone continued to grow, filling the crater. The dome had reached the same height as the highest part of the crater rim, formed during 2002. Intense fumarolic activity produced continuous plumes. The dome was thought to have formed during 2011, growing at a rapid rate and producing high temperatures. IG also noted that seismicity had increased starting in May but was more pronounced during the previous few weeks. During 3-9 August cloud cover prevented observations of the lava dome, but the seismic network detected long-period and explosion-type earthquakes.
Volcano information: Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera.

STROMBOLI Aeolian Islands (Italy) 38.789°N, 15.213°E; summit elev. 924 m
* Sezione di Catania - Osservatorio Etneo reported that during the morning of 9 August a new episode of weak spattering occurred on Stromboli's crater terrace, generating a small intra-crater lava flow. The source vent was located in the central portion of the crater terrace. Regular explosive activity also continued from the vents located in the N and S parts of the crater terrace. Spattering continued into the afternoon, then ceased.
Volcano information: Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean."Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.

 

For the list of volcanoes with Ongoing activity, please click here

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Comments

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