9-9-9-9-9-9-9-9-9-9-9-9-9 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 27 January-2 February 2021 Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm New Activity/Unrest: Karangetang, Siau Island (Indonesia) | Merapi, Central Java (Indonesia) | Raung, Eastern Java (Indonesia) | Sarychev Peak, Matua Island (Russia) | Soufriere St. Vincent, St. Vincent | Tinakula, Solomon Islands Ongoing Activity: Aira, Kyushu (Japan) | Dukono, Halmahera (Indonesia) | Ebeko, Paramushir Island (Russia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Klyuchevskoy, Central Kamchatka (Russia) | Lewotolo, Lomblen Island (Indonesia) | Nevados de Chillan, Chile | Semeru, Eastern Java (Indonesia) | Sheveluch, Central Kamchatka (Russia) | Sinabung, Indonesia | Suwanosejima, Ryukyu Islands (Japan) | Whakaari/White Island, North Island (New Zealand) 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 Karangetang | Siau Island (Indonesia) | 2.781°N, 125.407°E | Summit elev. 1797 m The Darwin VAAC reported that on 29 January a pilot observed an eruption plume rising from Karangetang to 2.4 km (8,000 ft) a.s.l. and drifted SW. The next day an ash plume identified in satellite images rose to 3 km (10,000 ft) a.s.l. and drifted SW. The Alert Level remained at 2 (on a scale of 1-4). Geologic Summary. Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi island. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia's most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented in the historical record (Catalog of Active Volcanoes of the World: Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows. Sources: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml; Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ Merapi | Central Java (Indonesia) | 7.54°S, 110.446°E | Summit elev. 2910 m BPPTKG reported that the â??2021 lava domeâ?? continued to effuse just below Merapiâ??s SW rim during 22-28 January, producing a total of 230 incandescent lava avalanches that traveled as far as 1.5 km down the Krasak and Boyong river drainages on the SW flank. Pyroclastic flows were recorded 71 times and descended the Boyong drainage as far as 3.5 km. A comparison of photos taken on 21 and 26 January showed that the morphological changes in the summit area were attributed to the emergence of lava domes. The 2021 dome volume was an estimated 157,000 cubic meters on 25 January, but avalanches and pyroclastic flows during 26-27 January reduced the volume to 62,000 cubic meters based on 28 January estimates. Deformation continued, though at a lower rate; Electronic Distance Measurement (EDM) data showed a distance shortening between points in the NW at a rate of 0.4 cm per day. There were 36 pyroclastic flows recorded during 0000-1400 on 27 January; the longest pyroclastic flow traveled 3 km down the Krasak and Boyong drainages at 1253. The corresponding ash plume rose into low weather clouds that obscured the summit. At 1335 pyroclastic flows traveled 1.5 km SW. Sirens were triggered in Ngrangkah, Umbulharjo, Cangkringan, and Sleman (along the Boyong river drainage), alerting about 150 residents to temporarily evacuate. Ashfall was reported in several villages in the Tamansari and Musuk districts, Boyolali Regency, Boyolali City, and several locations in Klaten. The Alert Level remained at 3 (on a scale of 1-4), and the public were warned to stay 5 km away from the summit. 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. Sources: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) http://www.merapi.bgl.esdm.go.id/; Detik News https://news.detik.com/berita-jawa-tengah/d-5350625/gunung-merapi-erupsi-besar-boyolali-diguyur-hujan-abu-campur-pasir?_ga=2.230047007.2076450499.1612195171-14950811.1611700211 ; Detik News https://news.detik.com/detiktv/d-5350835/suasana-saat-sirene-bahaya-merapi-erupsi-meraung?_ga=2.225787417.2076450499.1612195171-14950811.1611700211 ; Detik News https://news.detik.com/berita-jawa-tengah/d-5350638/gunung-merapi-erupsi-siang-tadi-warga-turgo-sleman-diungsikan?_ga=2.268236173.2076450499.1612195171-14950811.1611700211 ; Detik News https://news.detik.com/berita-jawa-tengah/d-5350981/gunung-merapi-erupsi-semburkan-awan-panas-36-kali-dalam-8-jam?_ga=2.100160157.2076450499.1612195171-14950811.1611700211 ; Detik News https://news.detik.com/berita-jawa-tengah/d-5350985/gunung-merapi-erupsi-siang-tadi-warga-turgo-sleman-diungsikan?_ga=2.256235656.2076450499.1612195171-14950811.1611700211 Raung | Eastern Java (Indonesia) | 8.119°S, 114.056°E | Summit elev. 3260 m PVMBG reported that daily gray-to-brown ash plumes rose 400-700 m above Raungâ??s summit and drifted SE, E, and NE during 26 January-2 February. Incandescence from the crater was often seen reflected in the emissions and rumbling was sometimes heard. At 2354 on 2 February an ash plume rose 1 km and drifted E. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone. 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. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ Sarychev Peak | Matua Island (Russia) | 48.092°N, 153.2°E | Summit elev. 1496 m KVERT reported that the eruption at Sarychev Peak continued during 22-29 January, characterized by lava effusion from the carter onto the N flank. A daily thermal anomaly was identified in satellite images. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale). Geologic Summary. Sarychev Peak, one of the most active volcanoes of the Kuril Islands, occupies the NW end of Matua Island in the central Kuriles. The andesitic central cone was constructed within a 3-3.5-km-wide caldera, whose rim is exposed only on the SW side. A dramatic 250-m-wide, very steep-walled crater with a jagged rim caps the volcano. The substantially higher SE rim forms the 1496 m high point of the island. Fresh-looking lava flows, prior to activity in 2009, had descended in all directions, often forming capes along the coast. Much of the lower-angle outer flanks of the volcano are overlain by pyroclastic-flow deposits. Eruptions have been recorded since the 1760s and include both quiet lava effusion and violent explosions. Large eruptions in 1946 and 2009 produced pyroclastic flows that reached the sea. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php Soufriere St. Vincent | St. Vincent | 13.33°N, 61.18°W | Summit elev. 1220 m University of the West Indies Seismic Research Centre (UWI-SRC) and National Emergency Management Organisation (NEMO) reported that the lava dome in Soufrière St. Vincentâ??s main crater was an estimated 428 m long, 217 m wide, 80 m high, and had a volume of 4.45 million cubic meters by 27 January. The dome continued to grow during 27 January-2 February. During a field visit on 1 February scientists observed that gas-and-steam continued to rise from the top of the dome as well as along the contact of the old and new domes. Gas-and-steam plumes were often visible from Belmont Observatory. The Alert Level remained at Orange (the second highest level on a four-color scale). Geologic Summary. Soufrière St. Vincent is the northernmost and youngest volcano on St. Vincent Island. The NE rim of the 1.6-km wide summit crater is cut by a crater formed in 1812. The crater itself lies on the SW margin of a larger 2.2-km-wide caldera, which is breached widely to the SW as a result of slope failure. Frequent explosive eruptions after about 4,300 years ago produced pyroclastic deposits of the Yellow Tephra Formation, which cover much of the island. The first historical eruption took place in 1718; it and the 1812 eruption produced major explosions. Much of the northern end of the island was devastated by a major eruption in 1902 that coincided with the catastrophic Mont Pelée eruption on Martinique. A lava dome was emplaced in the summit crater in 1971 during a strictly effusive eruption, forming an island within a lake that filled the crater. A series of explosive eruptions in 1979 destroyed the 1971 dome and ejected the lake; a new dome was then built. Sources: University of the West Indies Seismic Research Centre (UWI-SRC) http://www.uwiseismic.com/; National Emergency Management Organisation (NEMO), Government of Saint Vincent and the Grenadines http://nemo.gov.lc/ Tinakula | Solomon Islands | 10.386°S, 165.804°E | Summit elev. 796 m Thermal anomalies over Tinakulaâ??s summit and on the WNW flank were periodically visible in satellite images during 17 December 2020-21 January 2021. Weather clouds often obscured views. Geologic Summary. The small 3.5-km-wide island of Tinakula is the exposed summit of a massive stratovolcano at the NW end of the Santa Cruz islands. Similar to Stromboli, it has a breached summit crater that extends from the summit to below sea level. Landslides enlarged this scarp in 1965, creating an embayment on the NW coast. The satellitic cone of Mendana is located on the SE side. The dominantly andesitic volcano has frequently been observed in eruption since the era of Spanish exploration began in 1595. In about 1840, an explosive eruption apparently produced pyroclastic flows that swept all sides of the island, killing its inhabitants. Frequent historical eruptions have originated from a cone constructed within the large breached crater. These have left the upper flanks and the steep apron of lava flows and volcaniclastic debris within the breach unvegetated. Source: Sentinel Hub https://sentinel-hub.com/explore/sentinel-playground Ongoing Activity Aira | Kyushu (Japan) | 31.593°N, 130.657°E | Summit elev. 1117 m JMA reported that during 25 January-1 February incandescence from Minamidake Crater (at Aira Calderaâ??s Sakurajima volcano) was often visible at night. Ten explosions generated eruption plumes that rose 1.8-2.3 km above the crater rim and ejected bombs 800-1,100 km away from the crater. The Alert Level remained at 3 (on a 5-level scale). 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 Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ Dukono | Halmahera (Indonesia) | 1.693°N, 127.894°E | Summit elev. 1229 m PVMBG reported that during 26 January-2 February ash plumes from Dukono rose 100-600 m above the summit and drifted W, SW, and W. Weather conditions sometimes prevented visual observations. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone. 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, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the north-flank cone of Gunung Mamuya. 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/ Ebeko | Paramushir Island (Russia) | 50.686°N, 156.014°E | Summit elev. 1103 m Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 22, 24-25, and 27 January that sent ash plumes to 3.1 km (10,200 ft) a.s.l. and drifted ESE. Ashfall was reported in Severo-Kurilsk on 24 January. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). 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 Karymsky | Eastern Kamchatka (Russia) | 54.049°N, 159.443°E | Summit elev. 1513 m KVERT reported that a thermal anomaly over a lava dome in Karymskyâ??s summit crater was visible in satellite images during 21-24 and 27 January. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m HVO reported that lava from a vent on a cone on the inner NW wall of Kilaueaâ??s Halema`uma`u Crater fed flows that traveled down a channel into a perched lava lake during 27-29 January. The vent was mostly crusted over during 30 January-2 February, though several incandescent areas on cone were visible and lava slowly effused from the base of the cone. The western half of the lake deepened from 209 to 212 m and was elevated ~5 m above the stagnant E half. Geologic Summary. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 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 km2, destroying nearly 200 houses and adding new coastline to the island. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) https://volcanoes.usgs.gov/observatories/hvo/ Klyuchevskoy | Central Kamchatka (Russia) | 56.056°N, 160.642°E | Summit elev. 4754 m KVERT reported that Strombolian and sometimes Vulcanian activity at Klyuchevskoy continued during 22-29 January and lava advanced down the Kozyrevsky drainage on the S flank and the Apakhonchich drainage on the SE flank. A large bright thermal anomaly was identified daily in satellite images. Steam-and-gas plumes with some ash rose to 6 km (19,700 ft) a.s.l. and drifted 125 km in multiple directions. On 24 January collapses from the lava flow sent large amounts of material and pyroclastic flows down the Apakhonchich drainage. An ash cloud rose to 9.6 km (31,500 ft) a.s.l. and drifted 60 km N then NE. The Aviation Color Code remined at Orange (the second highest level on a four-color scale). Geologic Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php Lewotolo | Lomblen Island (Indonesia) | 8.274°S, 123.508°E | Summit elev. 1431 m PVMBG reported that the eruption at Lewotolo continued at least during 26-28 January. Gray-and-white ash plumes rose 500 m above the summit and drifted E, SE, and W. Strombolian explosions ejected material 500 m above the summit, and incandescent material was ejected as far as 500-600 m SE from the crater. Rumbling was reported during 29-30 January; weather conditions prevented visual observations of the crater during 29 January-2 February. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 4 km away from the summer crater. Geologic Summary. The Lewotolo (or Lewotolok) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ Nevados de Chillan | Chile | 36.868°S, 71.378°W | Summit elev. 3180 m SERNAGEOMIN reported that activity at Nevados de Chillánâ??s Nicanor Crater was ongoing with sporadic gas-and-ash emissions and continuing lava effusion through 1 February. Lava effusion began in mid-2020 though the rate had increased in the past two months. A satellite image from 25 January showed a thermal anomaly over the lava dome in Nicanor Crater and one on the N crater rim, at the vent producing lava flows. A minor thermal anomaly was visible at the end of the active â??L5â?? lava flow, about 600 m N of the vent. The Alert Level remained at Yellow, the second lowest level on a four-color scale, and residents were reminded not to approach the crater within 3 km. ONEMI stated that Alert Level Yellow (the middle level on a three-color scale) remained in place for the communities of Pinto and Coihueco, noting that the public should stay at least 3 km away from the crater on the W and SW flank and 5 km away on the NE flank. Geologic Summary. The compound volcano of Nevados de Chillán is one of the most active of the Central Andes. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km into the Central Depression of Chile. The largest stratovolcano, dominantly andesitic, Cerro Blanco (Volcán Nevado), is located at the NW end of the group. Volcán Viejo (Volcán Chillán), which was the main active vent during the 17th-19th centuries, occupies the SE end. The new Volcán Nuevo lava-dome complex formed between 1906 and 1945 between the two volcanoes and grew to exceed Volcán Viejo in elevation. The Volcán Arrau dome complex was constructed SE of Volcán Nuevo between 1973 and 1986 and eventually exceeded its height. Sources: Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) http://www.sernageomin.cl/; Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI) http://www.onemi.cl/ Semeru | Eastern Java (Indonesia) | 8.108°S, 112.922°E | Summit elev. 3657 m PVMBG reported that the eruption at Semeru continued during 27 January-2 February, though weather conditions often prevented visual confirmation. On 28 January incandescent material was seen being ejected 50 m above the summit. According to a news article a pyroclastic flow from the end of a lava flow traveled 2 km down the flank on 2 February. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 4 km in the SSE sector. 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/ Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 22-29 January. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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 Sinabung | Indonesia | 3.17°N, 98.392°E | Summit elev. 2460 m PVMBG reported that at 1822 on 27 January an ash plume from Sinabung rose 500 m above the summit and drifted SE and E, according to a ground-based observer. Dense white plumes rose as high as 1 km above them summit during 28 January-2 February. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km in the SE sector and 4 km in the NE sector. Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical andesitic-to-dacitic edifice is at the southern end of the four overlapping summit craters. The youngest deposit is a SE-flank pyroclastic flow 14C dated by Hendrasto et al. (2012) at 740-880 CE. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks in 1912. No confirmed historical eruptions were recorded prior to explosive eruptions during August-September 2010 that produced ash plumes to 5 km above the summit. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ Suwanosejima | Ryukyu Islands (Japan) | 29.638°N, 129.714°E | Summit elev. 796 m JMA reported that incandescence at Suwanosejimaâ??s Ontake Crater was occasionally visible at night during 22-29 January. Intermittent explosions produced ash plumes that rose as high as 1.4 km above the crater rim and ejected bombs 200 m away from the crater. The Alert Level remained at 2 (on a 5-level scale). Geologic Summary. The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed 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 the horseshoe-shaped Sakuchi caldera, which extends 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/ Whakaari/White Island | North Island (New Zealand) | 37.52°S, 177.18°E | Summit elev. 294 m GeoNet reported that during the previous year temperatures of Whakaari/White Islandâ??s steam and gas vents were regularly captured during helicopter overflights. These data showed a downward trend from temperatures of over 700 degrees Celsius in February 2020 to temperatures around 300 degrees Celsius recorded on 21 January. The recent gas-emission temperatures were similar to those measured in July 2018. There was no evidence of eruptive activity observed during overflights in January nor signs of collapse in or near the active vents. A small amount of water had ponded on the 1978/90 Crater floor. Gas continued to be emitted from the active vents and from cooling lava that had erupted in December 2019, though the emission rates were the lowest recorded since that eruption. The Volcanic Alert Level remained at 1 and the Aviation Color Code remained at Green. 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/ 9-9-9-9-9-9-9-9-9-9-9-9-9 ============================================================== 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). ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - http://www.volcano.si.edu/ IAVCEI - https://www.iavceivolcano.org/ To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx. To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments. ============================================================== ------------------------------ End of Volcano Digest - 27 Jan 2021 to 3 Feb 2021 (#2021-10) ************************************************************
