1-1-1-1-1-1-1-1-1-1-1-1-1-1 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 24-30 November 2021 Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvHvJw8Dc$ <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrOo96j6Y$> New Activity/Unrest: Iliwerung, Lomblen Island (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Pinatubo, Luzon (Philippines) | Ulawun, New Britain (Papua New Guinea) Ongoing Activity: Aira, Kyushu (Japan) | Bagana, Bougainville (Papua New Guinea) | Ebeko, Paramushir Island (Russia) | Etna, Sicily (Italy) | Great Sitkin, Andreanof Islands (USA) | Grimsvotn, Iceland | Heard, Kerguelen Plateau | Katmai, United States | Kilauea, Hawaiian Islands (USA) | La Palma, Spain | Lewotolok, Lembata Island (Indonesia) | Merapi, Central Java (Indonesia) | Nyiragongo, DR Congo | Pavlof, United States | Reventador, Ecuador | Sangay, Ecuador | Semisopochnoi, Aleutian Islands (USA) | Sheveluch, Central Kamchatka (Russia) | Stromboli, Aeolian Islands (Italy) | Suwanosejima, Ryukyu Islands (Japan) | Yasur, Vanuatu 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 Iliwerung | Lomblen Island (Indonesia) | 8.532°S, 123.573°E | Summit elev. 583 m A submarine eruption at Iliwerung was observed during 28-29 November, prompting PVMBG to raise the Alert Level to 2 (on a scale of 0-4). Residents reported seeing the sea surface, 30 m from the shore to the S, bubbling up to heights of less than 1 m beginning at 2152 on 28 November; the activity lasted about an hour. Eruptive activity at the sea surface was again observed at 0517 on 29 November. An observer described bubbling water and a plume rising about 100 m a few hours later, at 0829, though they noted that the activity was about 1 km S of the Hobal submarine vent (about 3 km E of the summit), the site of multiple eruptions since 1973. PVMBG warned residents to stay away from the coastline and the water nearest to the activity. Geologic Summary. Constructed on the southern rim of the Lerek caldera, Iliwerung forms a prominent south-facing peninsula on Lembata (formerly Lomblen) Island. Craters and lava domes have formed along N-S and NW-SE lines on the complex volcano; activity has been observed at vents from the summit to the submarine SE flank. The summit lava dome was formed during an eruption in 1870. In 1948 the Iligripe lava dome grew on the E flank at 120 m elevation. Beginning in 1973-74, when three ephemeral islands were formed, submarine eruptions began on the lower ESE flank at a vent named Hobal; several other eruptions have since taken place at this vent. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvnKkm4QM$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr0S5pweU$> Karymsky | Eastern Kamchatka (Russia) | 54.049°N, 159.443°E | Summit elev. 1513 m KVERT reported that during 18-20 and 25 November explosions at Karymsky generated ash plumes that rose as high as 6.5 km (21,300 ft) a.s.l. and drifted 370 km NE and NW. A thermal anomaly was visible in satellite images during 18-19 and 22 November. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvOKm2EfU$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrbCHI6NM$> Pinatubo | Luzon (Philippines) | 15.13°N, 120.35°E | Summit elev. 1486 m PHIVOLCS reported that a weak phreatic explosion at Pinatubo was recorded during 1209-1213 on 30 November. The event was likely drive by shallow hydrothermal processes based on very low seismicity recorded during the previous few days, low diffuse carbon dioxide flux from the lake, and a notable infrasound signal. A plume mostly comprised of steam was seen rising above weather clouds within a few minutes of the end of the event. The Tokyo VAAC stated that the plume rose to 13.4 km (44,000 ft) a.s.l. and drifted W based on satellite data. Geologic Summary. Prior to 1991 Pinatubo volcano was a relatively unknown, heavily forested lava dome complex located 100 km NW of Manila with no records of historical eruptions. The 1991 eruption, one of the world's largest of the 20th century, ejected massive amounts of tephra and produced voluminous pyroclastic flows, forming a small, 2.5-km-wide summit caldera whose floor is now covered by a lake. Caldera formation lowered the height of the summit by more than 300 m. Although the eruption caused hundreds of fatalities and major damage with severe social and economic impact, successful monitoring efforts greatly reduced the number of fatalities. Widespread lahars that redistributed products of the 1991 eruption have continued to cause severe disruption. Previous major eruptive periods, interrupted by lengthy quiescent periods, have produced pyroclastic flows and lahars that were even more extensive than in 1991. Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS) https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvEFaYQYk$ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrmZSh2m0$> ; Tokyo Volcanic Ash Advisory Center (VAAC) https://urldefense.com/v3/__http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsv7dSYzzo$ <https://urldefense.com/v3/__http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lrrp3TmsE$> Ulawun | New Britain (Papua New Guinea) | 5.05°S, 151.33°E | Summit elev. 2334 m The Darwin VAAC raised the Aviation Color Code for Ulawun to Orange (the second highest level on a four-color scale) on 30 November based on reports of unrest by local observers. The reports described increased seismicity, steam emissions, and a small ash eruption the day before. Geologic Summary. The symmetrical basaltic-to-andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. The volcano, also known as the Father, rises above the N coast of the island of New Britain across a low saddle NE of Bamus volcano, the South Son. The upper 1,000 m is unvegetated. A prominent E-W escarpment on the south may be the result of large-scale slumping. Satellitic cones occupy the NW and E flanks. A steep-walled valley cuts the NW side, and a flank lava-flow complex lies to the south of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater. Source: Darwin Volcanic Ash Advisory Centre (VAAC) https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsv3oVCixg$ <https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrOWiUwZ8$> Ongoing Activity Aira | Kyushu (Japan) | 31.593°N, 130.657°E | Summit elev. 1117 m JMA reported that incandescence from Minamidake Crater (at Aira Calderaâ??s Sakurajima volcano) was visible at night during 22-29 November. An eruptive event at 1509 on 25 November generated a plume that rose 1 km above the crater rim. The sulfur dioxide emission rate was slightly high at 1,200 tons per day on 26 November; sulfur dioxide emissions had been generally high since late September 2020. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater. Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvAsnDqXg$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LryPPVRYA$> Bagana | Bougainville (Papua New Guinea) | 6.137°S, 155.196°E | Summit elev. 1855 m The Darwin VAAC reported that on 27 November ash plumes from Bagana rose to 2.1 km (7,000 ft) a.s.l. and drifted NW based on satellite and wind model data. Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. This massive symmetrical cone was largely constructed by an accumulation of viscous andesitic lava flows. The entire edifice could have been constructed in about 300 years at its present rate of lava production. Eruptive activity is frequent and characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50 m thick with prominent levees that descend the flanks on all sides. Source: Darwin Volcanic Ash Advisory Centre (VAAC) https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsv3oVCixg$ <https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrOWiUwZ8$> Ebeko | Paramushir Island (Russia) | 50.686°N, 156.014°E | Summit elev. 1103 m On 26 November KVERT lowered the Aviation Color Code for Ebeko to Yellow (the second lowest level on a four-color scale), noting that a thermal anomaly was last identified on 25 October and eruptive activity was last recorded on 9 November. Gas-and-steam emission continued to be visible. Geologic Summary. The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvOKm2EfU$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrbCHI6NM$> Etna | Sicily (Italy) | 37.748°N, 14.999°E | Summit elev. 3320 m INGV reported that gas emissions from Etnaâ??s summit craters were visible during 15-21 November, though weather clouds sometimes prevented webcam observations. At 1116 on 20 November an explosion at Northeast Crater (NEC) produced diffuse ash-and-gas plumes that quickly dissipated near the summit. Geologic Summary. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank. Source: Sezione di Catania - Osservatorio Etneo (INGV) https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvfOZ1KRI$ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr3lPYoOk$> Great Sitkin | Andreanof Islands (USA) | 52.076°N, 176.13°W | Summit elev. 1740 m According to AVO satellite images acquired on 23 November showed that lava effusion at Great Sitkin continued, though at a low rate. Lava continued to fill the summit crater and the flows on the flanks advanced short distances. During 24-30 November seismicity remained slightly above background levels. Elevated surface temperatures were periodically detected. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively. Geologic Summary. The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger parasitic volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an ancestral volcano and produced a submarine debris avalanche. Deposits from this and an older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Historical eruptions have been recorded since the late-19th century. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvlfHKwkw$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrNnODQSg$> Grimsvotn | Iceland | 64.416°N, 17.316°W | Summit elev. 1719 m On 24 November Icelandic Meteorological Office (IMO) reported that the ice sheet in GrÃmsvötn's caldera had subsided 60 cm in the previous few days and the rate of subsidence had accelerated in the last day. By 29 November the ice had sunk a total of 5 m and by 1 December the subsidence totaled 10 m. Data indicated that water had likely begun exiting the caldera and will result in a jökulhlaup (glacial outburst flood) that will cause flooding conditions in drainages. Water levels in the GÃgjukvÃsl drainage rose overnight during 30 November-1 December. Geologic Summary. GrÃmsvötn, Iceland's most frequently active volcano in historical time, lies largely beneath the vast Vatnajökull icecap. The caldera lake is covered by a 200-m-thick ice shelf, and only the southern rim of the 6 x 8 km caldera is exposed. The geothermal area in the caldera causes frequent jökulhlaups (glacier outburst floods) when melting raises the water level high enough to lift its ice dam. Long NE-SW-trending fissure systems extend from the central volcano. The most prominent of these is the noted Laki (Skaftar) fissure, which extends to the SW and produced the world's largest known historical lava flow during an eruption in 1783. The 15-cu-km basaltic Laki lavas were erupted over a 7-month period from a 27-km-long fissure system. Extensive crop damage and livestock losses caused a severe famine that resulted in the loss of one-fifth of the population of Iceland. Source: Icelandic Meteorological Office (IMO) https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvcPgepxI$ <https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lrj48HUk8$> Heard | Kerguelen Plateau | 53.106°S, 73.513°E | Summit elev. 2745 m Thermal satellite images of Heard Islandâ??s Big Ben volcano showed thermal anomalies of varying intensity over the summit area or on the NW and W flanks on 4, 11, 14, and 21 November. Weather clouds prevented views of the volcano on eight other acquisitions during the month. On 11 November four anomalies on the NW flank formed a â??vâ?? shape open to the NW, possibly indicating a branched lava flow. On 21 November the anomaly was on the W flank and possible emissions from the E and SE margins of it drifted SE. Geologic Summary. Heard Island on the Kerguelen Plateau in the southern Indian Ocean consists primarily of the emergent portion of two volcanic structures. The large glacier-covered composite basaltic-to-trachytic cone of Big Ben comprises most of the island, and the smaller Mt. Dixon lies at the NW tip of the island across a narrow isthmus. Little is known about the structure of Big Ben because of its extensive ice cover. The historically active Mawson Peak forms the island's high point and lies within a 5-6 km wide caldera breached to the SW side of Big Ben. Small satellitic scoria cones are mostly located on the northern coast. Several subglacial eruptions have been reported at this isolated volcano, but observations are infrequent and additional activity may have occurred. Source: Sentinel Hub https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvvPRnlUw$ <https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrPb13_DI$> Katmai | United States | 58.28°N, 154.963°W | Summit elev. 2047 m AVO reported that on 25 November strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE over Shelikof Strait and Kodiak Island at an altitude up to 1.5 km (5,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912. The Volcano Alert Level remained at Normal and the Aviation Color Code remained at Green. Geologic Summary. Prior to 1912, Mount Katmai was a compound stratovolcano with four NE-SW-trending summits, most of which were truncated by caldera collapse in that year. Two or more large explosive eruptions took place from Mount Katmai during the late Pleistocene. Most of the two overlapping pre-1912 Katmai volcanoes are Pleistocene in age, but Holocene lava flows from a flank vent descend the SE flank of the SW stratovolcano into the Katmai River canyon. Katmai was initially considered to be the source of the Valley of Ten Thousand Smokes ash flow in 1912. However, the 3 x 4 km wide caldera of 1912 is now known to have formed as a result of the voluminous eruption at nearby Novarupta volcano. The steep walled young caldera has a jagged rim that rises 500-1000 m above the caldera floor and contains a 250-m-deep, still-rising lake. Lake waters have covered a small post-collapse lava dome (Horseshoe Island) that was seen on the caldera floor at the time of the initial ascent to the caldera rim in 1916. Post-1912 glaciers have formed on a bench within Katmai caldera. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvlfHKwkw$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrNnODQSg$> Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m HVO reported that the summit eruption at Kilauea continued at a vent in the lower W wall of Halema`uma`u Crater during 24-30 November. The vent contained ponded and sometimes spattering lava that fed the lake through the E part of the W wall cone. The size of the active part of the lake varied, and lava periodically oozed from the cooler, outer margins of the lake onto the lowest of the exposed down-dropped caldera floor blocks. Earthquake activity remained below background levels and volcanic tremor was elevated. The sulfur dioxide emission rate had averaged 3,000 tonnes per day in recent weeks; on 23 November the rate was higher at 6,400 tonnes per day and on 29 November it was below the average at 1,200 tonnes per day. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively. 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://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvIEoAIcs$ <https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrpZ5Kt5E$> La Palma | Spain | 28.57°N, 17.83°W | Summit elev. 2426 m The eruption at La Palma continued during 24-30 November, characterized by Strombolian explosions and lava fountaining/jetting from multiple existing and new vents, advancing and sometimes branching lava flows, and daily ash emissions. The eruption began on 19 September and had been active for 70 days by 28 November. Volcanic tremor levels were low, though during 28-29 November levels fluctuated and were sometimes intense. Seismicity persisted at variable but elevated levels, with earthquake locations distributed at depths of 10-15 km and 30-40 km. Deeper seismicity decreased to low levels by 27 November while mid-level seismicity intensified through the week. The largest earthquake was a M 5 recorded at 0935 on 29 November at a depth of 36 km. A M 4.2 earthquake at a depth of 13 km was the largest event at mid-levels since the eruption began. Several vents in the main cone continued to effuse lava, eject tephra, and emit ash-and-gas plumes. Lava moved W through pre-existing lava channels, lava tubes, over older flows, and over new ground, increasing the flow field that consists of overlapping flows (numbered 1-11) and two lava deltas. During 23-25 November flows 4, 5, and 7 at the N end of the flow field continued to widen and advance, filling in gaps between the flows, and fed the N delta. Flows 1, 2, and 9 minimally fed the S delta. There was also an increasing number of active flows on the flow field as lava overflowed some channel margins or broke out of tubes. At around 0900 on 25 November the lava effusion rate increased at main crater vents, and around 1100 two small E-W fissures opened less than 1 km S of the main cone. The easternmost vent produced a fast-moving lava flow that traveled along the S margin of flow 10 and around the S side of Montaña Cogote. The flow advanced through the Las Manchas cemetery and inundated parts of a solar power plant; the newly covered areas were part of the exclusion zone and had already been evacuated. The flow rate slowed to about 25 m per hour and joined flow 11 by 26 November. An overflow of lava SW of flow 3 produced a small branch oriented laterally the flow margin. Flow 7 widened during 26-27 November as it continued to be fed. New vents opened on the NE flank of the main cone at around 0300 on 28 November, producing fluid lava flows that traveled N and NW through the Tacande area and crossed the LP-212 road. The opening of the new vents was followed by landslides on the NW flank of the cone. In a video taken at 1145 lava fountains rose from one of the vents while another ejected tephra. Dense billowing ash plumes rose from the main crater. Video taken at 1050 on 29 November showed lava flows transporting large blocks downslope. Another video showed lava flowing at a rate of about 1 m per second. By noon the vents in the main cone became notably less active and remained only intermittently active through 30 November. Several streams of lava from the new vents continued to advance NW and then W along older flows and split into two branches. One branch traveled through tubes and fed flows 4, 5, and 7 between Montaña de Todoque and Montaña de La Laguna and the other descended towards flow 8 (the most northern flow). Flows inundated previously untouched forest and agricultural land. By 30 November the width of the flow field had grown to 3.35 km and lava covered an estimated 11.34 square kilometers. The number of people that had evacuated and were staying in hotels had increased to 537. Gas and ash emissions again impacted island residents. Suspended ash and high concentrations of volcanic gases triggered a few air-quality alerts mostly affecting the W part of the island; authorities warned residents of some affected areas to stay indoors. Essential personnel were occasionally barred from entering the exclusion zones to irrigate crops and remove ash from streets and buildings. Heavy rains during 25-26 November triggered warnings from authorities to stay away from steep slopes and drainages due to the possibility of lahars. Ash plumes rose as high as 4.8 km and drifted E during 24-26 November, and continued to deposit ash at La Palma airport. By 27 November winds had shifted and the ash at the airport had been removed, allowing it to open for the first time since 20 November. Ash plumes rose 1.4-3.5 km and drifted SW and SSW during the rest of the week. Sulfur dioxide emissions continued an overall downward trend during 23-26 November, though heavy rain sometimes prevented ground-based measurements. The trend was broken on 27 and 28 November with values of 30,000-49,999 tons per day, characterized as â??very high.â?? During 29-30 November emission values were â??highâ?? or between values of 1,000 and 29,999 tons per day. Geologic Summary. The 47-km-long wedge-shaped island of La Palma, the NW-most of the Canary Islands, is composed of two large volcanic centers. The older northern one is cut by the massive steep-walled Caldera Taburiente, one of several massive collapse scarps produced by edifice failure to the SW. The younger Cumbre Vieja, the southern volcano, is one of the most active in the Canaries. The elongated volcano dates back to about 125,000 years ago and is oriented N-S. Eruptions during the past 7,000 years have formed abundant cinder cones and craters along the axis of Cumbre Vieja, producing fissure-fed lava flows that descend steeply to the sea. Eruptions recorded since the 15th century have produced mild explosive activity and lava flows that damaged populated areas. The southern tip of the island is mantled by a broad lava field emplaced during the 1677-1678 eruption. Lava flows also reached the sea in 1585, 1646, 1712, 1949, and 1971. Sources: Instituto Volcanológico de Canarias (INVOLCAN) https://urldefense.com/v3/__http://www.involcan.org/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsvpz5PHwI$ <https://urldefense.com/v3/__http://www.involcan.org/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrwcVGbtw$> ; Instituto Geográfico Nacional (IGN) https://urldefense.com/v3/__https://www.ign.es/web/ign/portal__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvnWdiyxU$ <https://urldefense.com/v3/__https://www.ign.es/web/ign/portal__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr9rXAHoE$> ; Gobierno de Canaries https://urldefense.com/v3/__http://www.gobcan.es/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvTkHAwWs$ <https://urldefense.com/v3/__http://www.gobcan.es/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrLcqEo0I$> Lewotolok | Lembata Island (Indonesia) | 8.274°S, 123.508°E | Summit elev. 1431 m PVMBG reported that the eruption at Lewotolok continued during 24-30 November. Daily white-and-gray ash plumes rose as high as 1 km above the summit. Crater incandescence was visible each day, with eruptions accompanied by rumbling and roaring sounds. Incandescent material was ejected 300-500 m E and SE from the vent during 24-25 November. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater. Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvnKkm4QM$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr0S5pweU$> Merapi | Central Java (Indonesia) | 7.54°S, 110.446°E | Summit elev. 2910 m BPPTKG reported no notable morphological changes to Merapiâ??s SW lava dome, located just below the SW rim, or the dome in the summit crater during 19-25 November. The estimated dome volumes remained stable at 1.61 million cubic meters for the SW dome and almost 2.93 million cubic meters for the summit dome. As many as 110 lava avalanches traveled a maximum of 2 km SW. One pyroclastic flow traveled 1.8 km SW on 20 November. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-5 km away from the summit based on location. Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvLTUBaY8$ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrQ1twUso$> Nyiragongo | DR Congo | 1.52°S, 29.25°E | Summit elev. 3470 m OVG reported that active vents on the crater floor of Nyiragongo were seen ejecting spatter on 27 November. Geologic Summary. One of Africa's most notable volcanoes, Nyiragongo contained a lava lake in its deep summit crater that was active for half a century before draining catastrophically through its outer flanks in 1977. The steep slopes of a stratovolcano contrast to the low profile of its neighboring shield volcano, Nyamuragira. Benches in the steep-walled, 1.2-km-wide summit crater mark levels of former lava lakes, which have been observed since the late-19th century. Two older stratovolcanoes, Baruta and Shaheru, are partially overlapped by Nyiragongo on the north and south. About 100 parasitic cones are located primarily along radial fissures south of Shaheru, east of the summit, and along a NE-SW zone extending as far as Lake Kivu. Many cones are buried by voluminous lava flows that extend long distances down the flanks, which is characterized by the eruption of foiditic rocks. The extremely fluid 1977 lava flows caused many fatalities, as did lava flows that inundated portions of the major city of Goma in January 2002. Source: Observatoire Volcanologique de Goma (OVG) https://urldefense.com/v3/__http://observatoirevolcanologiquedegoma.org/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsvs4qCWO0$ <https://urldefense.com/v3/__http://observatoirevolcanologiquedegoma.org/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrEY--mTA$> Pavlof | United States | 55.417°N, 161.894°W | Summit elev. 2493 m AVO reported that the eruption at Pavlof continued during 23-30 November, focused at a vent on the upper SE flank. Low lava fountaining that had begun on 14 November continued to construct an unstable cone over the vent. Hot rubbly lava flows from the cone traveled a few hundred meters down the flanks, melting snow and ice that resulted in narrow lahars which traveled several kilometers down the flanks; satellite data from 25 November showed a new debris flow extending downslope from the end of the lava flow. Seismicity remained elevated; a few small explosions were detected during 24-26 and 28-30 November. Elevated surface temperatures were periodically observed in satellite data, though cloud cover sometimes prevented observations. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. Geologic Summary. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvlfHKwkw$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrNnODQSg$> Reventador | Ecuador | 0.077°S, 77.656°W | Summit elev. 3562 m IG reported that a high level of activity continued to be recorded at Reventador during 24-30 November. Gas-and-ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose higher than 1.3 km above the summit crater and drifted mainly NW, W, SW, and S. Crater incandescence was visible nightly, and incandescent blocks were observed rolling 400 m down the flanks in all directions on most nights. Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic Volcán El Reventador stratovolcano rises to 3562 m above the jungles of the western Amazon basin. A 4-km-wide caldera widely breached to the east was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1300 m above the caldera floor to a height comparable to the caldera rim. It has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. The largest historical eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents. Source: Instituto GeofÃsico-Escuela Politécnica Nacional (IG) https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvbVWwAVg$ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr6od1PEE$> Sangay | Ecuador | 2.005°S, 78.341°W | Summit elev. 5286 m IG reported that thermal anomalies, persistent at Sangay since July, suggested continuous emission of lava flows and hot pyroclastic material from summit crater vents. The SE drainage, which had been scoured and widened by persistent pyroclastic flows during August 2019 to March 2020, had only widened from about 600 m to about 650 m during March-October. An increased number of explosions and an inflationary trend were recorded during the previous few weeks. Strombolian activity began to dominate the eruptive style in July, though on 17 November the number of explosions increased to two per minute and remained at that level at least through 23 November. Most of the explosions were small and were recorded both by the seismic and acoustic networks. Though slight inflation began to be detected in June 2021 the trend was more pronounced in recent weeks. InSAR satellite data showed an inflationary trend of up to 5 cm per year all around the volcano except the E flank between 5 January 2020 and 13 November 2021. The sulfur dioxide emission rate had remained stable and low since June, with values less than 1,000 tons per day. Daily ash-and-gas plumes were identified by the Washington VAAC or in IG webcam views during 23-29 November. The plumes rose 970-2,100 m above the volcano and drifted NW, W, SW, and S. Daily thermal anomalies over the volcano were often visible in satellite data. Strombolian activity at summit vents and SE-descending lava flows were visible during 23-24 November. A new vent was possibly identified on the upper W flank. Two lahars were detected by the seismic network on 25 November. 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 horseshoe-shaped 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 sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of a historical eruption was in 1628. More or less 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. Source: Instituto GeofÃsico-Escuela Politécnica Nacional (IG) https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvbVWwAVg$ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr6od1PEE$> Semisopochnoi | Aleutian Islands (USA) | 51.93°N, 179.58°E | Summit elev. 1221 m AVO reported that eruptive activity at Semisopochnoi's North Cerberus crater continued during 24-30 November. Daily minor explosions were detected in seismic and infrasound data. Weather clouds obscured satellite and webcam views of the volcano on most days; small ash plumes rising no higher than 3 km (10,000 ft) a.s.l. were sometimes visible during breaks in the cloud cover but were likely emitted daily. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch. Geologic Summary. Semisopochnoi, the largest subaerial volcano of the western Aleutians, is 20 km wide at sea level and contains an 8-km-wide caldera. It formed as a result of collapse of a low-angle, dominantly basaltic volcano following the eruption of a large volume of dacitic pumice. The high point of the island is Anvil Peak, a double-peaked late-Pleistocene cone that forms much of the island's northern part. The three-peaked Mount Cerberus was constructed within the caldera during the Holocene. Each of the peaks contains a summit crater; lava flows on the N flank of Cerberus appear younger than those on the south side. Other post-caldera volcanoes include the symmetrical Sugarloaf Peak SSE of the caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake in the NE part of the caldera. Most documented eruptions have originated from Cerberus, although Coats (1950) considered that both Sugarloaf and Lakeshore Cone could have been recently active. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvlfHKwkw$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrNnODQSg$> Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 19-26 November. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvOKm2EfU$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrbCHI6NM$> Stromboli | Aeolian Islands (Italy) | 38.789°N, 15.213°E | Summit elev. 924 m INGV reported that during 15-28 November activity at Stromboli was characterized by ongoing explosive activity from five vents in Area N (North Crater area) and four vents in Area C-S (South-Central Crater area). Explosions from Area N vents (N1 and N2) averaged 6-17 events per hour; explosions from two vents in the N1 vent ejected lapilli and bombs 80 m high and explosions at three N2 vents ejected material 80-150 m high. Spattering at N2 was sometimes intense. No explosions occurred at the S1 and C vents in Area C-S; explosions at the two S2 vents occurred at a rate of 4-9 per hour and ejected coarse material as high as 80 m. Drone footage acquired on 20 November captured two C-S vents ejecting shreds of lava and one emitting gas. A 60-m-line of fumaroles, oriented NNW, were situated on the Sciara del Fuoco, down-flank of Area N. During the morning of 21 November intense spattering occurred at a vent between N1 and N2 produced a rheomorphic lava flow, formed by the accumulated spatter, on the upper middle part of the Sciara del Fuoco. At 0751 on 25 November lava blocks originating from a hornito in the N2 area began rolling downslope. Within a few hours a lava flow was visible in the same area; blocks from the end of the flow descended the Sciara del Fuoco, reaching the coastline. The rate of lava effusion varied during 25-26 November; the flow had begun cooling by the evening of 27 November. Geologic Summary. Spectacular incandescent nighttime explosions at this volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout 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 horseshoe-shaped scarp formed about 5,000 years ago due to a series of slope failures that extend 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) https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvfOZ1KRI$ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-Lr3lPYoOk$> Suwanosejima | Ryukyu Islands (Japan) | 29.638°N, 129.714°E | Summit elev. 796 m JMA reported that during 22-29 November about 41 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.7 km above the crater rim and ejected blocks 500-800 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater. Geologic Summary. The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvAsnDqXg$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LryPPVRYA$> Yasur | Vanuatu | 19.532°S, 169.447°E | Summit elev. 361 m The Vanuatu Meteorology and Geohazards Department (VMGD) and the Wellington VAAC reported that multiple gas-and-ash emissions at Yasur were visible in webcam images on 27 November rising 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifting W. Weather clouds prevented satellite observations of the emissions. The Alert Level remained at 2 (on a scale of 0-4). Geologic Summary. Yasur, the best-known and most frequently visited of the Vanuatu volcanoes, has been in more-or-less continuous Strombolian and Vulcanian activity since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island, this mostly unvegetated pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide, horseshoe-shaped caldera associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century. Sources: Vanuatu Meteorology and Geo-Hazards Department (VMGD) https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsv3OXm19M$ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LreeXw868$> ; Wellington Volcanic Ash Advisory Center (VAAC) https://urldefense.com/v3/__http://vaac.metservice.com/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvpKn2Oho$ <https://urldefense.com/v3/__http://vaac.metservice.com/__;!!IKRxdwAv5BmarQ!LEJqn8LOipitM13fGpmn1xsS_4fSGTdNwtPsLAU4lY_wLgTgN72C_-LrzaQSkIU$> 1-1-1-1-1-1-1-1-1-1-1-1-1-1 ============================================================== Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI). ASU - http://www.asu.edu/ PSU - https://urldefense.com/v3/__http://pdx.edu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5BmsvUpL5nmc$ GVP - https://urldefense.com/v3/__http://www.volcano.si.edu/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsvgm3WLJs$ IAVCEI - https://urldefense.com/v3/__https://www.iavceivolcano.org/__;!!IKRxdwAv5BmarQ!LS-9rMPE6kff2LCGJDgvajw1bg_ZRxrg93kwqxYwMi15yGXDm3v5Bmsv2qzxP80$ 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 - 1 Dec 2021 to 2 Dec 2021 (#2021-116) ************************************************************
