6-6-6-6-6-6-6-6-6-6-6-6-6 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 11-17 December 2024 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBq51953YA$> New Activity/Unrest: Ahyi, United States | Dukono, Indonesia | Home Reef, Tonga | Kanlaon, Philippines | Kirishimayama, Japan | Raung, Indonesia | Whakaari/White Island, New Zealand Ongoing Activity: Aira, Japan | Ebeko, Russia | Great Sitkin, United States | Ibu, Indonesia | Lewotobi, Indonesia | Merapi, Indonesia | Semeru, Indonesia | Sheveluch, Russia | Suwanosejima, Japan | Taal, Philippines 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, these reports 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 about recent activity are published in issues of the Bulletin of the Global Volcanism Network. Note that many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source. New Activity/Unrest Ahyi | United States | 20.42°N, 145.03°E | Summit elev. -75 m No plumes of discolored water surrounding Ahyi Seamount were identified in satellite images during 7-13 December and no significant signals were identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale). Geologic Summary. Ahyi seamount is a large conical submarine volcano that rises to within 75 m of the ocean surface ~18 km SE of the island of Farallon de Pajaros in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations. Source: US Geological Survey https://www.usgs.gov/ <https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBonHl1Wdg$> Dukono | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono was ongoing during 11-17 December. A dense black, gray, and white ash plume rose 3 km above the summit and drifted NW on 11 December. White-and-gray ash plumes rose 100-1,500 m above the crater rim and drifted in multiple directions during 12-13, 15, and 17 December. White plumes rose 200-300 m and drifted S and E on 14 December and no emissions were visible on 16 December. The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater. Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBoz-PWvXg$> Home Reef | Tonga | 18.992°S, 174.775°W | Summit elev. -10 m The Tonga Geological Services reported that a thermal anomaly at Home Reef was identified in satellite data at 0115 on 4 December. Thermal anomalies persisted at least through 13 December. The Maritime Alert Level was raised to Orange (the second highest level on a four-color scale) and mariners were advised to stay 4 km away from the island, the Aviation Color Code remained at Green (the lowest color on a four-color scale), and the Alert Level for residents of Vavaâ??u and Haâ??apai remained at Green (the lowest color on a four-color scale). A comparison of satellite images from 7 and 12 December showed that a new lobe of lava had flowed to the NE, expanding the coastline. There was also a thermal anomaly over the central part of the island. Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption. Sources: Tonga Geological Services, Government of Tonga https://www.facebook.com/tongageologicalservice <https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBrS5ztBLw$> ; Copernicus https://www.copernicus.eu/en <https://urldefense.com/v3/__https://www.copernicus.eu/en__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBos8kwCeQ$> Kanlaon | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 11-17 December. The seismic network recorded 2-32 daily volcanic earthquakes, and sulfur dioxide emissions ranged from 3,620 to 8,600 tonnes per day. Gas-and-steam emissions that were continuous rose 50-100 m above the summit and drifted mainly W, WSW, SSW, and SW; weather clouds obscured views on 11 and 13 December. There were 1-6 ash emission events during 3-5 and 7-8 December, with each lasting 3-40 minutes. Periodic ash emissions were recorded during the week: two ash emission events lasting 11-29 minutes occurred on 10 December, 13 ash emission events on 12 December were as short as two minutes and as long as 78 minutes, and four ash emission events on 16 December lasted 6-35 minutes. The Disaster Response Operations Monitoring and Information Center (DROMIC) report issued at 2000 on 17 December stated that 15,391 people (4,865 families) were spread across 32 evacuation centers and another 2,711 people (803 families) were staying elsewhere. The report also stated that 40 people involved with farming or fishing were affected, a total of 21.27 hectares of agricultural fields were damaged, and 32 cities had declared a â??state of calamityâ??. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano. Geologic Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall. Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBplg85uzw$> ; Disaster Response Operations Monitoring and Information Center (DROMIC) https://dromic.dswd.gov.ph/ <https://urldefense.com/v3/__https://dromic.dswd.gov.ph/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBonwWrQ6Q$> Kirishimayama | Japan | 31.934°N, 130.862°E | Summit elev. 1700 m The Japan Meteorological Agency (JMA) reported increasing unrest at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group). The Global Navigation Satellite System (GNSS) indicated minor inflation starting in November 2023. The number of earthquakes with epicenters beneath Shinmoedake had been increasing since late October 2023; during 1-11 December 2024 the seismic network detected 284 earthquakes. At 1100 on 12 December the Alert Level was raised to 2 (on a 5-level scale) and the public was warned to stay 2 km away from Shinmoedake Crater. Sulfur dioxide emissions were below detectable limits on 3 and 9 December. Geologic Summary. Kirishimayama is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene dominantly andesitic group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located Karakunidake being the highest. Onamiike and Miike, the two largest maars, are located SW of Karakunidake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Miike to Ohachi, and at Shinmoedake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBofuIjqQw$> Raung | Indonesia | 8.119°S, 114.056°E | Summit elev. 3260 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) issued a Volcano Observatory Notice for Aviation (VONA) for Raung at 1751 on 12 December, noting that white plumes rose 500 m above the summit and volcanic tremor was recorded by the seismic network. Increasing volcanic activity prompted the release of another VONA at 2003 on 15 December; the Aviation Color Code was raised to Yellow (the second lowest color on a four-color scale). An eruptive event produced a medium-dense to dense ash plume that rose 500 m above the summit and drifted E and SE. According to the Darwin VAAC the ash plume had dissipated by 0940 on 16 December. The Alert Level remained at 2 (on a scale of 1-4) and the pubic was warned to stay 3 km away from the summit crater. Geologic Summary. Raung, one of Java's most active volcanoes, is a massive stratovolcano in easternmost Java that was constructed SW of the rim of Ijen caldera. The unvegetated summit is truncated by a dramatic steep-walled, 2-km-wide caldera that has been the site of frequent historical eruptions. A prehistoric collapse of Gunung Gadung on the W flank produced a large debris avalanche that traveled 79 km, reaching nearly to the Indian Ocean. Raung contains several centers constructed along a NE-SW line, with Gunung Suket and Gunung Gadung stratovolcanoes being located to the NE and W, respectively. Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBoz-PWvXg$> ; Darwin Volcanic Ash Advisory Centre (VAAC) http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml <https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBoeiRN_Xg$> Whakaari/White Island | New Zealand | 37.52°S, 177.18°E | Summit elev. 294 m On 12 December GeoNet reported that larger steam-and-gas plumes were recently being emitted from Whakaari/White Island. During an overflight on 5 December scientists observed a vivid white steam-and-gas plume rising from the vent area with no detected ash. There were no new ash deposits in the crater or on the island, and the plume was relatively cool at 150 degrees Celsius. During 1500-1800 on 10 December a larger steam-and-gas plume was visible in images from webcams located at Whakatane and Te Kaha, as well as in satellite images. Additional larger plumes were sometimes visible when weather conditions allowed during 10-12 December. Sulfur dioxide emissions detected by satellite had generally increased during the previous two weeks. During a gas monitoring overflight on 14 December scientists observed the emissions changing to include more ash content. The gas data showed increases in sulfur dioxide and carbon dioxide emissions, possibly indicating the start of a new eruptive episode. On 16 December the Aviation Color Code was raised to Orange (the second highest level on a four-color scale). The Volcanic Alert Level remained at 2 (on a scale of 0-5). GeoNet stated that the Alert Levels were reflective of the current level of activity, but there was uncertainty due to the current lack of consistent, usable, real-time monitoring data. Geologic Summary. The uninhabited Whakaari/White Island is the 2 x 2.4 km emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The island consists of two overlapping andesitic-to-dacitic stratovolcanoes. The SE side of the crater is open at sea level, with the recent activity centered about 1 km from the shore close to the rear crater wall. Volckner Rocks, sea stacks that are remnants of a lava dome, lie 5 km NW. Descriptions of volcanism since 1826 have included intermittent moderate phreatic, phreatomagmatic, and Strombolian eruptions; activity there also forms a prominent part of Maori legends. The formation of many new vents during the 19th and 20th centuries caused rapid changes in crater floor topography. Collapse of the crater wall in 1914 produced a debris avalanche that buried buildings and workers at a sulfur-mining project. Explosive activity in December 2019 took place while tourists were present, resulting in many fatalities. The official government name Whakaari/White Island is a combination of the full Maori name of Te Puia o Whakaari ("The Dramatic Volcano") and White Island (referencing the constant steam plume) given by Captain James Cook in 1769. Source: GeoNet http://www.geonet.org.nz/ <https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBrWDI9jow$> Ongoing Activity Aira | Japan | 31.5772°N, 130.6589°E | Summit elev. 1117 m The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Calderaâ??s Sakurajima volcano) during 9-16 December. Nightly crater incandescence was visible in webcam images and small eruptive events were occasionally recorded during the week. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 1 km away from both craters. Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim and built an island that was joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4,850 years ago, after which eruptions took place at Minamidake. Frequent eruptions since the 8th century have deposited ash on the city of Kagoshima, located across Kagoshima Bay only 8 km from the summit. The largest recorded eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBofuIjqQw$> Ebeko | Russia | 50.686°N, 156.014°E | Summit elev. 1103 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate activity was ongoing at Ebeko during 5-12 December. Explosions during 9-10 December generated ash plumes that drifted NE, according to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E). Satellite images indicated that the volcano was quiet or obscured by weather clouds. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are UTC; specific events are in local time where noted. Geologic Summary. The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBo7hBHKxg$> Great Sitkin | United States | 52.076°N, 176.13°W | Summit elev. 1740 m The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick lava flow in Great Sitkinâ??s summit crater during 10-17 December. Minor lava flow advancement along the N margins had gradually filled the summit crater. The local seismic network continued to detect small earthquakes associated with the ongoing eruption. Nothing notable was identified in satellite and webcam images, though weather clouds occasionally obscured webcam and satellite views The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale). Geologic Summary. The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an older edifice and produced a submarine debris avalanche. Deposits from this and an even older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Eruptions have been recorded since the late-19th century. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBpRWZCUEA$> Ibu | Indonesia | 1.488°N, 127.63°E | Summit elev. 1325 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 11-17 December. Gray or white-and-gray ash plumes that were often dense rose 0.3-1.2 km above the summit and drifted in multiple directions on most days; emissions were not reported on 15 December likely due to weather clouds. Webcam images posted with 11 December reports showed incandescence at the summit of the inner active cone. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5.5 km away from the N crater wall opening. Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBoz-PWvXg$> Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Lewotobi Laki-laki during 11-17 December. White-and-gray ash plumes that were sometimes dense rose as high as 800 m above the summit and drifted in multiple directions during 11 and 13-14 December. White plumes rose as high as 700 m above the summit and drifted N, NW, W, and SW on 12 and 16 December. Eruptive events were recorded on 15 December, though weather conditions prevented visual confirmation. The Alert Level remained at 4 (on a scale of 1-4) and the public was warned to stay 6 km away from the center of Laki-laki and 7 km in a semicircle counterclockwise from the NE to the SW. Geologic Summary. The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the "husband and wife"). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBoz-PWvXg$> Merapi | Indonesia | 7.54°S, 110.446°E | Summit elev. 2910 m The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 6-12 December. Seismicity remained at high levels. The SW lava dome produced 113 lava avalanches that traveled as far as 1.8 km SW down the Bebeng drainage and 43 that traveled SW down the Krasak drainage. Morphological changes to the SW lava dome resulted from continuing effusion and collapses of material. The SW dome grew larger and was an estimated 3,315,200 cubic meters based on an analysis of webcam images. The volume of the main crater was stable at an estimated 2,361,800 cubic meters. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit, based on location. Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) http://www.merapi.bgl.esdm.go.id/ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBrvRhAiJQ$> Semeru | Indonesia | 8.108°S, 112.922°E | Summit elev. 3657 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Semeru during 4-10 December with several daily eruptive events recorded by the seismic network. White-and-gray or gray ash plumes that were sometimes dense rose 400-1,000 m above the summit and drifted in multiple directions during 13-15 and 17 December. Emissions were not observed on the other days of the week. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards. Geologic Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBoz-PWvXg$> Sheveluch | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava extrusion may have continued at Sheveluchâ??s â??300 years of RASâ?? dome on the SW flank of Old Sheveluch and at the dome at Young Sheveluch during 5-12 December. Daily thermal anomalies over the domes were identified in satellite images. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBo7hBHKxg$> Suwanosejima | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 9-16 December. Crater incandescence was observed nightly in webcam images. Blocks were ejected as far as 300 m from the center of the crater. Eruptive events at 1231 on 12 December, at 0750 on 13 December, at 1908 on 14 December, and at 0341 on 15 December produced ash plumes that rose 1-1.2 km above the cater rim and drifted S and SE; the plumes on 12 and 13 December rose into weather clouds. An explosion was recorded at 1213 on 15 December, though no emissions were reported. Another explosion at 0221 on 16 December produced an ash plume that rose 800 m above the crater rim and drifted E. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater. Geologic Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBofuIjqQw$> Taal | Philippines | 14.0106°N, 120.9975°E | Summit elev. 311 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Taal during 10-17 December. Daily emissions that were mostly diffuse rose 400-600 m above the crater rim and drifted SW and WSW. There were 3-10 daily occurrences of volcanic tremor during 10-12 December, with highly variable periods of between three minutes to six hours. Two volcanic earthquakes were recorded on 15 December. Sulfur dioxide gas emissions averaged 2,825 tonnes per day (t/d) on 11 December and 5,800 t/d on 14 December. An advisory issued at 1745 on 16 December stated that of sulfur dioxide emissions had reached 8,322 t/d, higher than the yearâ??s average of 6,057 t/d. The Alert Level remained at 1 (on a scale of 0-5); PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited. Geologic Summary. Taal is one of the most active volcanoes in the Philippines and has produced some powerful eruptions. The 15 x 20 km Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2 surface lies only 3 m above sea level. The maximum depth of the lake is 160 m, with several submerged eruptive centers. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!bREeedhYgwXpFaMV-YzI-dhMVOC8ymvtlr6WgT3MRr6Wx61NdJohilgjcxLtpwpPI0bV_qepWG-UNkCxMBplg85uzw$> 6-6-6-6-6-6-6-6-6-6-6-6-6 ============================================================== Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI). 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