4-4-4-4-4-4-4-4-4-4-4-4-4 From: "Bennis, Kadie" <BennisK@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 16 October-22 October 2024 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) Kadie Bennis â?? Weekly Report Writer (*bennisk@xxxxxx <bennisk@xxxxxx>*) URL: https://volcano.si.edu/reports_weekly.cfm <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AWxou45g$> New Activity/Unrest: Cerro Hudson, Chile | Copahue, Chile-Argentina | Etna, Italy | Iya, Indonesia | Kanlaon, Philippines | Spurr, United States Ongoing Activity: Aira, Japan | Dukono, Indonesia | Ebeko, Russia | Fuego, Guatemala | Great Sitkin, United States | Ibu, Indonesia | Karymsky, Russia | Katmai, United States | Kuchinoerabujima, Japan | Langila, Papua New Guinea | Lewotobi, Indonesia | Marapi, Indonesia | Merapi, Indonesia | Nevado del Ruiz, Colombia | Nyamulagira, DR Congo | Popocatepetl, Mexico | Reventador, Ecuador | Rincon de la Vieja, Costa Rica | Sabancaya, Peru | Sangay, Ecuador | Santa Maria, Guatemala | Semeru, Indonesia | Sheveluch, Russia | Stromboli, Italy | Suwanosejima, Japan | Taal, Philippines | Whakaari/White 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* *Cerro Hudson* | Chile | 45.9°S, 72.97°W | Summit elev. 1905 m Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) reported an increase in seismicity associated with rock-fracturing at Hudson starting at 1200 on 16 October, with a total of 160 volcano-tectonic earthquakes. The highest magnitude earthquake of 2.5 occurred at 1416 on 17 October, which was located 2.9 km ESE from the center of the caldera and at a depth of 4.4 km. A long-period earthquake was detected at 1638 on 17 October. A volcano-tectonic earthquake was detected at 0245 on 19 October. The Alert Level remained at Green (the lowest level on a four-color scale). Geologic Summary. The ice-filled, 10-km-wide caldera of Cerro Hudson volcano was not recognized until its first 20th-century eruption in 1971. It is the southernmost volcano in the Chilean Andes, related to subduction of the Nazca plate beneath the South American plate. The massive volcano covers an area of 300 km2. The compound caldera is drained through a breach on its NW rim, which has been the source of mudflows down the RÃo de Los Huemeles. Two cinder cones occur N of the volcano and others occupy the SW and SE flanks. This volcano has been the source of several major Holocene explosive eruptions. An eruption about 6,700 years ago was one of the largest known in the southern Andes during the Holocene; another eruption about 3,600 years ago also produced more than 10 km3 of tephra. An eruption in 1991 formed a new 800-m-wide crater in the SW portion of the caldera. Source: Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) http://www.sernageomin.cl/ <https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BsFQVL9w$> *Copahue* | Chile-Argentina | 37.856°S, 71.183°W | Summit elev. 2953 m Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) reported nighttime crater incandescence at Copahue on 16 October. According to Servicio Geológico Minero Argentino (SEGEMAR), webcam images recorded an increase in surface activity at 0430 on 19 October, which consisted of an ash emission that rose 200 m above the crater and drifted SE. The Alert Level remained at Green (the lowest level on a four-color scale) and the public was reminded to stay 500 m away from the crater. Geologic Summary. Volcán Copahue is an elongated composite cone constructed along the Chile-Argentina border within the 6.5 x 8.5 km wide Trapa-Trapa caldera that formed between 0.6 and 0.4 million years ago near the NW margin of the 20 x 15 km Pliocene Caviahue (Del Agrio) caldera. The eastern summit crater, part of a 2-km-long, ENE-WSW line of nine craters, contains a briny, acidic 300-m-wide crater lake (also referred to as El Agrio or Del Agrio) and displays intense fumarolic activity. Acidic hot springs occur below the eastern outlet of the crater lake, contributing to the acidity of the RÃo Agrio, and another geothermal zone is located within Caviahue caldera about 7 km NE of the summit. Infrequent mild-to-moderate explosive eruptions have been recorded since the 18th century. Twentieth-century eruptions from the crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments. Sources: Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) http://www.sernageomin.cl/ <https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BsFQVL9w$> ; Servicio Geológico Minero Argentino (SEGEMAR) http://www.segemar.gov.ar/ <https://urldefense.com/v3/__http://www.segemar.gov.ar/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0ASgykfcA$> *Etna* | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m Sezione di Catania - Osservatorio Etneo (INGV) reported that during 14-20 October activity at Etna was characterized by continuous intra-crater explosive activity at NE Crater, mild and sporadic ash emissions from SE Crater, and degassing activity from the summit craters, based on webcam images. During 17-20 October weather conditions prevented clear observations. The Aviation Color Code was raised from Yellow to Orange at 1538 on 21 October. Geologic Summary. Mount Etna, towering above Catania on the island of Sicily, has one of the world's longest documented records of volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank. Source: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AXiD_l6w$> *Iya* | Indonesia | 8.891°S, 121.641°E | Summit elev. 618 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that there was an increase in activity and potential hazards at Iya, based on visual and instrumental monitoring data during 16-22 October. The Alert Level was raised to 2 (on a scale of 1-4) at 0800 on 17 October, and the public was warned to stay 2 km away from the active crater area. Geologic Summary. Gunung Iya is the southernmost of a group of three volcanoes comprising a small peninsula south of the city of Ende on central Flores Island. The cones to the north, Rooja and Pui, appear to be slightly older and have not shown historical activity, although Pui has a youthful profile (a reported 1671 eruption of Pui was considered to have originated from Iya volcano). Iya, whose truncated southern side drops steeply to the sea, has had numerous moderate explosive eruptions during historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Cl80l5iw$> *Kanlaon* | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Kanlaon during 16-22 October, characterized by elevated seismicity and sulfur dioxide emissions. Visual monitors recorded continuous degassing, with brief episodes when gray ash was entrained in the plume. Three â??ashingâ?? events, at 0641, 0701, and 0801 on 19 October, lasted two to six minutes long, based on visual observations; no detectable seismic or infrasound signals were recorded. The events generated light-gray plumes that rose 500 m above the crater and drifted SW. Traces of ash deposits were reported in the barangays of Yubo and Ara-al, La Carlota City (14 km W), and Sag-ang, La Castellana (16 km SW). A sulfur dioxide odor was also reported in Yubo. The seismic network recorded 6-19 daily volcanic earthquakes. Daily gas-and-steam emissions that were sometimes voluminous rose 200-900 m above the summit and drifted W, SW, S, and SE. Sulfur dioxide emissions were recorded during 16-20 October and continued to be high, averaging 2,679-6,477 tonnes/day. The Alert Level remained at 2 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone and warned pilots 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. 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BP1ZfZfQ$> *Spurr* | United States | 61.299°N, 152.251°W | Summit elev. 3374 m The Alaska Volcano Observatory (AVO) reported that low-level unrest at Spurr was ongoing, characterized by elevated seismicity and deformation, and minor gas-and-steam emissions were visible in webcams. A small lake was present in the summit crater during 15 May to 15 June. The Volcano Alert Level was raised to Advisory (the second highest level on a four-level scale) and the Aviation Color Code was raised to Yellow (the second highest level on a four-color scale) at 1237 on 16 October. Geologic Summary. Mount Spurr is the closest volcano to Anchorage, Alaska (130 km W) and just NE of Chakachamna Lake. The summit is a large lava dome at the center of a roughly 5-km-wide amphitheater open to the south formed by a late-Pleistocene or early Holocene debris avalanche and associated pyroclastic flows that destroyed an older edifice. The debris avalanche traveled more than 25 km SE, and the resulting deposit contains blocks as large as 100 m in diameter. Several ice-carved post-collapse cones or lava domes are present. The youngest vent, Crater Peak, formed at the southern end of the amphitheater and has been the source of about 40 identified Holocene tephra layers. Eruptions from Crater Peak in 1953 and 1992 deposited ash in Anchorage. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0D7w7JZ5A$> *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 14-21 October. Daily crater incandescence was visible in webcam images. An explosion at 0121 on 18 October generated an ash-and-gas plume that rose 1-4 km above the crater rim. The explosion ejected large blocks to a distance of 1.3 km from the vent. According to a field survey conducted on 18 October, sulfur dioxide emissions were measured at 2,500 tons per day (t/d). 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BA_FOI3g$> *Dukono* | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono was ongoing during 16-21 October. Daily dense gray-and-white ash plumes rose 100-800 m above the summit and drifted E and NE. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone. Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Cl80l5iw$> *Ebeko* | Russia | 50.686°N, 156.014°E | Summit elev. 1103 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate explosive activity was ongoing at Ebeko during 11-17 October. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 16-17 October generated ash plumes that rose as high as 2.5 km (8,200 ft) a.s.l. and drifted NE. Thermal anomalies were identified in satellite images on 15 October; on other days either no activity was observed, or weather conditions prevented views. 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0A2WSWkcg$> *Fuego* | Guatemala | 14.473°N, 90.88°W | Summit elev. 3763 m Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) reported that eruptive activity continued at Fuego during 16-21 October. Daily explosions were recorded by the seismic network, averaging 3-12 per hour when reported. The explosions generated gas-and-ash plumes that rose as high as 1.2 km above the crater rim and drifted as far as 30 km SW, SE, and S. Weak rumbling sounds and shock waves from explosions were occasionally reported. The explosions often produced avalanches of material that descended the flanks, sometimes reaching vegetated areas. On most days, explosions ejected incandescent material up to 200 m above the summit. During the afternoon and evening of 16 October lahars descended the Ceniza, Zarco, Seca, and Mineral drainage, carrying tree branches, trunks, and blocks as large as 1.5 m in diameter. Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BkirI96w$> *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 16-22 October. The lava flow had filled most of the summit crater with minor advancement in the N part of the E lobe. The local seismic network continued to detect small earthquakes associated with the ongoing eruption. Weather clouds often obscured webcam and satellite views of the summit. 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0D7w7JZ5A$> *Ibu* | Indonesia | 1.488°N, 127.63°E | Summit elev. 1325 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 17-22 October. Near daily gray or white-and-gray ash plumes that were sometimes dense generally rose 500-1,500 m above the summit and drifted NE and E; a gray ash plume rose 4 km above the summit and drifted N and NE at 0126 on 16 October and another one rose 3 km above the summit and drifted NE and E at 2315 on 17 October. Nighttime incandescence was visible in a webcam image taken on 16 October. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5 km away from the N crater wall opening. Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Cl80l5iw$> *Karymsky* | Russia | 54.049°N, 159.443°E | Summit elev. 1513 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported moderate levels of activity at Karymsky during 11-17 October. Explosions on 11, 15, and 17 October produced ash plumes that rose as high as 6 km (20,000 ft) a.s.l. and drifted 200 km to the SE and NE. A thermal anomaly over the volcano was identified in satellite images on 15 and 17 October; the volcano exhibited no activity or weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. 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 <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0A2WSWkcg$> *Katmai* | United States | 58.279°N, 154.9533°W | Summit elev. 2047 m The Alaska Volcano Observatory (AVO) reported that during 18-19 October strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes dispersed unconsolidated ash up to 1.8 km (6,000 ft) a.s.l. to the SE and NW. The ash was originally deposited during the Novarupta-Katmai eruption in 1912. The Volcano Alert Level remained at Normal (the lowest level on a four-level scale) and the Aviation Color Code remained at Green (the lowest level on a four-color scale). Geologic Summary. Katmai was initially considered to be the source of the Valley of Ten Thousand Smokes ash flow in 1912. However, the 3 x 4 km caldera of 1912 is now known to have formed as a result of the voluminous eruption at nearby Novarupta volcano. The edifice had four NE-SW-trending summits, most of which were truncated by the 1912 collapse. Two or more large explosive eruptions took place during the late Pleistocene. Most of the two overlapping pre-1912 Katmai volcanoes are Pleistocene, but Holocene lava flows from a flank vent descend the SE flank of the SW edifice into the Katmai River canyon. The steep walled young caldera has a jagged rim that rises 500-1,000 m above the caldera floor and contains a deep lake. Lake waters have covered a small post-collapse lava dome (Horseshoe Island) that was seen on the caldera floor at the time of the initial ascent to the caldera rim in 1916. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0D7w7JZ5A$> *Kuchinoerabujima* | Japan | 30.443°N, 130.217°E | Summit elev. 657 m The Japan Meteorological Agency (JMA) reported that volcanic activity at Kuchinoerabujima had been declining since mid-August. The number of shallow volcanic earthquakes that had been frequent since the beginning of April, with most epicenters located near Furudake Crater, and few near Shindake Crater (just N of Furudake), have declined. The Alert Level was lowered to 2 (on a scale of 1-5) at 1100 on 18 October due to the decreased seismicity. Sulfur dioxide gas emissions were at low levels. The public was warned that ejected blocks and pyroclastic flows may impact areas within 1 km of both craters and within 2 km of Shindake. Geologic Summary. A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km W of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. All historical eruptions have occurred from Shindake, although a lava flow from the S flank of Furudake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shindake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BA_FOI3g$> *Langila* | Papua New Guinea | 5.525°S, 148.42°E | Summit elev. 1330 m The Darwin VAAC reported that an ash plume at Langila, identified in satellite images during 1720 on 18 October to 0900 on 19 October, rose to 1.8 km (6,000 ft) a.s.l. and drifted NW. Geologic Summary. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower E flank of the extinct Talawe volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the N and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml <https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0CGM5xPVA$> *Lewotobi* | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Lewotobiâ??s Laki-laki volcano continued during 16-22 October from a vent on the upper NW flank. Near daily gray or white-and-gray ash plumes that were sometimes dense rose as high as 1 km above the summit and drifted W, NW, and SW. The Alert Level remained at 3 (the second highest level on a scale of 1-4) and the public was warned to stay outside of the exclusion zone, defined as a 3 km radius around both Laki-laki and Perempuan craters, 4 km to the NNW and SSE of Laki-laki. 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Cl80l5iw$> *Marapi* | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) was ongoing during 16-22 October. Daily white emissions rose 50-400 m above the summit and drifted in multiple directions. On 22 October at 0139 an ash emission rose 800 m above the summit and drifted NW. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 3 km away from the active crater. Geologic Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Cl80l5iw$> *Merapi* | Indonesia | 7.54°S, 110.446°E | Summit elev. 2910 m The Balai Penyelidikan dan Pengembangan Teknologi Kegunungapian (BPPTK) reported that the eruption at Merapi (on Java) continued during 11-17 October. The number of multiple-phase and low-frequency earthquakes increased while the number of avalanche earthquakes decreased. The SW lava dome produced 302 lava avalanches that traveled as far as 1.9 km down the Bebeng drainage on the SW flank. There were morphological changes to the SW lava dome resulting from continuing effusion and collapses of material. 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 Kegunungapian (BPPTK) http://www.merapi.bgl.esdm.go.id/index.php <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/index.php__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AD-9OArQ$> *Nevado del Ruiz* | Colombia | 4.892°N, 75.324°W | Summit elev. 5279 m Servicio Geológico Colombianoâ??s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued during 15-21 October. The number of seismic events associated with fluid movement increased in both magnitude and number compared to the previous week, especially from seismic signals related to pulsating ash emissions, but were variable between low and moderate levels throughout the week. Webcam images confirmed ash emissions associated with some of these events. The highest temperature recorded for the week was on 16 October, associated with an ash emission at 0452 that rose 1.3 km above the crater. Another ash emission rose 2.2 km above the crater at 1637 on 19 October. Ashfall was reported in Cabaña de Brisas (NW), Aguacerales, and Recreo (Caldas and Tolima). Seismicity associated with rock fracturing remained similar in the number of events and magnitude compared to the previous week, with depths ranging from less than 1 km down to 8 km below the summit. The largest event was an M 1 which was detected at 1725 on 20 October. Sulfur dioxide emissions were variable, and drift directions were not towards measuring stations; satellite measurements indicated a slight decrease in emissions. Low-to-moderate thermal anomalies on the crater floor were identified in satellite data. The Alert Level remained at Yellow (the second level on a four-level scale), and the public was warned to stay out of the restricted areas around Arenas Crater, not to spend long periods of time on the Murillo-Cerro Gualà Road, and to avoid drainages in the high-threat zones. Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption. Source: Servicio Geológico Colombiano (SGC) https://www2.sgc.gov.co/volcanes/index.html <https://urldefense.com/v3/__https://www2.sgc.gov.co/volcanes/index.html__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0D8Jw8pdw$> *Nyamulagira* | DR Congo | 1.408°S, 29.2°E | Summit elev. 3058 m The Observatoire Volcanologique de Goma (OVG) reported that lava effusion at Nyamulagira was continuing. According to a special bulletin issued on 2 October, three lava flows were active on the N and W flanks, with the longest reaching 7 km NW from the crater rim. Strong seismicity in the area was also reported in a special bulletin issued on 14 October. During the nights of 13 and 14 October an intense glow was visible in the crater. Geologic Summary. Africa's most active volcano, Nyamulagira (also known as Nyamuragira), is a massive high-potassium basaltic shield about 25 km N of Lake Kivu and 13 km NNW of the steep-sided Nyiragongo volcano. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Documented eruptions have occurred within the summit caldera, as well as from the numerous flank fissures and cinder cones. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Recent lava flows extend down the flanks more than 30 km from the summit as far as Lake Kivu; extensive lava flows from this volcano have covered 1,500 km2 of the western branch of the East African Rift. Source: Observatoire Volcanologique de Goma (OVG) https://ovg-rdc.cd/ <https://urldefense.com/v3/__https://ovg-rdc.cd/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Bb8LcTxQ$> *Popocatepetl* | Mexico | 19.023°N, 98.622°W | Summit elev. 5393 m Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 16-22 October. The seismic network recorded 9-89 long-period events per day that were accompanied by steam-and-gas emissions. The seismic network also recorded daily tremor with periods lasting from 54 minutes up to 13 hours and 17 minutes, and a period of emissions that lasted 35 minutes during 15-16 October. Two volcano-tectonic earthquakes were recorded during 0100-0200 on 16 October. A single volcano-tectonic earthquake was detected at 1639 on 20 October. A significant tremor episode that began at 1147 was accompanied by a gas-and-ash plume that rose 2 km above the crater and incandescent material that was ejected a short distance from the crater. Based on information from El Centro Nacional de Comunicación y Operación de Protección Civil (CENACOM) ashfall was reported in Ozumba (18 km W), Tlalmanalco (30 km NW), and Ecatzingo (15 km SW) in the state of Mexico; and around 0958 in Tlalnepantla (80 km NW), Tlayacapan (40 km WSW), and Totolapan in the state of Morelos. According to the Washington VAAC ash plumes visible in webcam and satellite images during 17-21 October rose to 5.8-7.3 km (19,000-24,000 ft) a.s.l. and drifted in different directions. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater. Geologic Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time. Sources: Centro Nacional de Prevencion de Desastres (CENAPRED) https://www.gob.mx/cenapred <https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AObPA5Wg$> ; Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html <https://urldefense.com/v3/__http://www.ssd.noaa.gov/VAAC/messages.html__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AtAP60uQ$> *Reventador* | Ecuador | 0.077°S, 77.656°W | Summit elev. 3562 m Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) reported that an eruption at Reventador was ongoing during 18-22 October. Seismicity was characterized by 59-92 daily explosions, 17-23 long-period earthquakes, and 5-17 tremor events associated with emissions. During 19-22 October there were 2-5 harmonic tremor events recorded. Ash-and-gas plumes were observed in webcam images and/or satellite images rising 200-1,000 m above the crater and drifted in different directions. Crater incandescence was visible during 18-21 October and incandescent material was reported descending the flanks as far as 1,000 m below the crater. According to a webcam image, a pyroclastic flow occurred at 1701 on 19 October, traveling 800 m below the crater on the SE flank. SecretarÃa de Gestión de Riesgos maintained the Alert Level at Orange (the second highest level on a four-color scale). Geologic Summary. Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents. Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) http://www.igepn.edu.ec/ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AVHluofg$> ; SecretarÃa de Gestión de Riesgos (SGR) http://www.gestionderiesgos.gob.ec/ <https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BJ1oRi2Q$> *Rincon de la Vieja* | Costa Rica | 10.83°N, 85.324°W | Summit elev. 1916 m Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that a small eruption at Rincón de la Vieja was recorded at 0115 on 22 October, based on seismic and acoustic instruments. This event did not produce emissions with ash. Geologic Summary. Rincón de la Vieja, the largest volcano in NW Costa Rica, is a remote volcanic complex in the Guanacaste Range. The volcano consists of an elongated, arcuate NW-SE-trending ridge constructed within the 15-km-wide early Pleistocene GuachipelÃn caldera, whose rim is exposed on the south side. Sometimes known as the "Colossus of Guanacaste," it has an estimated volume of 130 km3 and contains at least nine major eruptive centers. Activity has migrated to the SE, where the youngest-looking craters are located. The twin cone of Santa MarÃa volcano, the highest peak of the complex, is located at the eastern end of a smaller, 5-km-wide caldera and has a 500-m-wide crater. A Plinian eruption producing the 0.25 km3 RÃo Blanca tephra about 3,500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous historical eruptions possibly dating back to the 16th century, have been from the prominent active crater containing a 500-m-wide acid lake located ENE of Von Seebach crater. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ <https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0CUVlHKiw$> *Sabancaya* | Peru | 15.787°S, 71.857°W | Summit elev. 5960 m Instituto GeofÃsico del Perú (IGP) reported that the eruption at Sabancaya continued during 14-20 October with a daily average of eight explosions. Gas-and-ash plumes rose as high as 1.7 km above the summit and drifted less than 10 km NW, E, and SE. Thermal anomalies over the lava dome in the summit crater were identified in satellite data. Slight inflation was detected N of Hualca Hualca (7 km N). Sulfur dioxide emissions were at moderate levels, averaging 548 tons per day. The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay outside of a 12 km radius. Geologic Summary. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of observed eruptions date back to 1750 CE. Source: Instituto GeofÃsico del Perú (IGP) http://www.igp.gob.pe/ <https://urldefense.com/v3/__http://www.igp.gob.pe/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0CJNax97Q$> *Sangay* | Ecuador | 2.005°S, 78.341°W | Summit elev. 5286 m Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) reported that high levels of eruptive activity continued at Sangay during 18-22 October. The seismic network recorded 45-460 daily explosions. Gas-and-ash plumes visible in webcam and/or satellite images on most days rose 300-2,000 m above the summit and drifted NW, NE, E, SE, and ENE. Several episodes of crater incandescence were observed, and incandescent material descended the flanks as far as 2 km. SecretarÃa de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale). Geologic Summary. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within the open calderas of two previous edifices which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex. Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) http://www.igepn.edu.ec/ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AVHluofg$> ; SecretarÃa de Gestión de Riesgos (SGR) http://www.gestionderiesgos.gob.ec/ <https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BJ1oRi2Q$> *Santa Maria* | Guatemala | 14.757°N, 91.552°W | Summit elev. 3745 m Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) reported ongoing eruptive activity at Santa Mariaâ??s Santiaguito cone during 16-21 October with continuing lava extrusion at Caliente dome. Daily explosions (a few per hour) generated gas-and-ash plumes that rose as high as 900 m above the summit and drifted mainly NW, S, and SW. Effusion of blocky lava and collapses of material produced block avalanches that descended the flanks. Incandescence was sometimes visible during dark hours from avalanches of material at the dome as well as explosions. Ashfall was reported in San Marcos (8 km SW) on 19 October. Geologic Summary. Symmetrical, forest-covered Santa MarÃa volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing E towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BkirI96w$> *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 16-22 October with multiple daily eruptive events recorded by the seismic network. Daily white-and-gray and gray-and-black ash plumes that were sometimes dense rose 400-800 m above the summit and drifted in various directions. 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0Cl80l5iw$> *Sheveluch* | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that during 11-17 October lava extrusion at Sheveluchâ??s may have continued at both the â??300 years of RASâ?? dome on the SW flank of Old Sheveluch and at the dome on Young Sheveluch. This activity was accompanied by strong gas-and-steam emissions. Thermal anomalies over the domes were identified in satellite images during the week. Plumes of resuspended ash drifted 25 km SE on 11 October. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0A2WSWkcg$> *Stromboli* | Italy | 38.789°N, 15.213°E | Summit elev. 924 m Sezione di Catania - Osservatorio Etneo (INGV) reported that eruptive activity continued at Stromboli during 14-20 October. Webcam images showed Strombolian activity at four vents in Area N within the upper part of the Sciara del Fuoco and from at least two vents in Area C-S (South-Central Crater) on the crater terrace. The vents in Area N continued to produce low-to-medium intensity explosions at a rate of 9-16 events per hour, ejecting lapilli and bombs less than 150 m above the vents. Spattering continued and was sometimes intense and continuous for long periods of time on 15 and 20 October. Explosions at the vents in Area C-S ejected tephra more than 250 m above the vent. An INGV inspection of the summit area occurred during 1000-1300 on 16 October. At least two vents were observed in the central part of Area C-S and were continuously degassing, and a third faced the wall of Pizzo Sopra la Fossa (an area atop the volcano about 100 m above the crater terrace). A single but intense ash emission rose over 300 m above the crater and was accompanied by small collapses of material. Ash emissions were also reporting rising from the two central vents. The Alert Level remained at Yellow (the second lowest level on a four-level scale). Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli have long attracted visitors to the "Lighthouse of the Mediterranean" in the NE Aeolian Islands. This volcano has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small island 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 Neostromboli eruptive period took place between about 13,000 and 5,000 years ago. The active summit vents are located at the head of the Sciara del Fuoco, a prominent scarp that formed about 5,000 years ago due to a series of slope failures which extends to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded for more than a millennium. Source: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AXiD_l6w$> *Suwanosejima* | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 14-22 October. An eruptive event at 0410 on 16 October produced an ash-and-gas plume that rose 1 km above the crater rim and drifted SW. An ash-and-gas plume at 0743 on 18 October and at 1706 on 22 October rose as high as 1.5 km above the crater rim and drifted NW and NE, respectively. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater. Geologic Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BA_FOI3g$> *Taal* | Philippines | 14.0106°N, 120.9975°E | Summit elev. 311 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that phreatic eruptive events at Taal periodically continued during 16-22 October. There were 1-2 phreatic events recorded almost daily during the week, with most lasting 2-14 minutes. Hot fluids upwelling in the lake were persistently observed, and daily steam-and-gas emissions that were sometimes voluminous rose as high as 1.8 km above the crater rim. Sulfur dioxide emissions averaged 1,577 tonnes per day (t/d) on 16 October and 1,256 t/d on 19 October. The Alert Level remained at 1 (on a scale of 0-5), and 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 and Taal Lake 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0BP1ZfZfQ$> *Whakaari/White Island* | New Zealand | 37.52°S, 177.18°E | Summit elev. 294 m On 22 October GeoNet reported that the eruption at Whakaari/White Island had ended, though gas-and-steam emissions remained variable. Based on observations from an overflight on 18 October and recent webcam and satellite images, the level of vent activity had decreased, with no evidence of eruptions or ash emissions. The Volcanic Alert Level was lowered to 2 (on a scale of 0-5) and the Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale). 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!aJhZeh9_c_kehFVTFOLtYpYILw85NlY07Ojmu84rE4cUxFpAtUwFSI41hwf8iBScApmGrfIP0YH369r8O0AL7VyJ8A$> 4-4-4-4-4-4-4-4-4-4-4-4-4 ============================================================== 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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