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 2-8 February 2022 Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI_KK4LFY$ <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwvF8uwsw$> New Activity/Unrest: Ambrym, Vanuatu | Chikurachki, Paramushir Island (Russia) | Hunga Tonga-Hunga Ha'apai, Tonga Ridge | Krakatau, Sunda Strait | Taal, Luzon (Philippines) | Villarrica, Central Chile | Wolf, Isla Isabela (Galapagos) Ongoing Activity: Aira, Kyushu (Japan) | Ambae, Vanuatu | Davidof, Aleutian Islands (USA) | Etna, Sicily (Italy) | Great Sitkin, Andreanof Islands (USA) | Kilauea, Hawaiian Islands (USA) | Lewotolok, Lembata Island | Merapi, Central Java | Pavlof, Alaska Peninsula, Alaska | Popocatepetl, Mexico | Rincon de la Vieja, Costa Rica | Sangay, Ecuador | Santa Maria, Southwestern Guatemala | Semeru, Eastern Java | Semisopochnoi, Aleutian Islands (USA) | Sheveluch, Central Kamchatka (Russia) | Suwanosejima, Ryukyu Islands (Japan) | Turrialba, Costa Rica | 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 Ambrym | Vanuatu | 16.25°S, 168.12°E | Summit elev. 1334 m On 2 February the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that sulfur dioxide gas emissions from Ambrym were detected in satellite images drifting E. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside of the Permanent Danger Zone A, defined as a 1-km radius around Benbow Crater and a 2-km radius around Marum Crater, and additionally to stay 500 m away from the ground cracks created by the December 2018 eruption. Geologic Summary. Ambrym, a large basaltic volcano with a 12-km-wide caldera, is one of the most active volcanoes of the New Hebrides Arc. A thick, almost exclusively pyroclastic sequence, initially dacitic then basaltic, overlies lava flows of a pre-caldera shield volcano. The caldera was formed during a major Plinian eruption with dacitic pyroclastic flows about 1,900 years ago. Post-caldera eruptions, primarily from Marum and Benbow cones, have partially filled the caldera floor and produced lava flows that ponded on the floor or overflowed through gaps in the caldera rim. Post-caldera eruptions have also formed a series of scoria cones and maars along a fissure system oriented ENE-WSW. Eruptions have apparently occurred almost yearly during historical time from cones within the caldera or from flank vents. However, from 1850 to 1950, reporting was mostly limited to extra-caldera eruptions that would have affected local populations. Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD) https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7d0thpY$ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwm_X5l_0$> Chikurachki | Paramushir Island (Russia) | 50.324°N, 155.461°E | Summit elev. 1781 m KVERT reported that the eruption at Chikurachki that began around 0300 on 31 January was over by 2 February. Explosions generated ash plumes that rose as high as 5 km (16,400 ft) a.s.l. and drifted as far as 255 km W, SW, S, and SE. The Aviation Color Code was lowered to Yellow on 3 February and to Green on 5 February, the lowest color on a four-color scale. Geologic Summary. Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is actually a relatively small cone constructed on a high Pleistocene volcanic edifice. Oxidized basaltic-to-andesitic scoria deposits covering the upper part of the young cone give it a distinctive red color. Frequent basaltic plinian eruptions have occurred during the Holocene. Lava flows from 1781-m-high Chikurachki reached the sea and form capes on the NW coast; several young lava flows also emerge from beneath the scoria blanket on the eastern flank. The Tatarinov group of six volcanic centers is located immediately to the south of Chikurachki, and the Lomonosov cinder cone group, the source of an early Holocene lava flow that reached the saddle between it and Fuss Peak to the west, lies at the southern end of the N-S-trending Chikurachki-Tatarinov complex. In contrast to the frequently active Chikurachki, the Tatarinov volcanoes are extensively modified by erosion and have a more complex structure. Tephrochronology gives evidence of only one eruption in historical time from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7-3vz34$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwIUtd3Qg$> Hunga Tonga-Hunga Ha'apai | Tonga Ridge | 20.536°S, 175.382°W | Summit elev. 114 m On 4 February the Tonga Geological Services (TGS) posted drone footage of the Good Samaritan Beach, located on the NE side of Tongatapu, showing that tsunamis from the 15 January Hunga Tonga-Hunga Ha'apai eruption reached areas at 15 m elevation, 200 m inland. A 6 February post provided details of what happened when tsunamis reached Mango Island (75 km ENE), stating that waves 12 m high went over the church tower, reached 500 m inland, and pushed buildings and structures against the inland wall of trees. Residents fled to an area that was 30 m elevation, 700 m from the coast, and stayed there all night as ash fell. TGS noted that clean-up efforts were continuing on the islands and communications were slowly being restored. Geologic Summary. The small andesitic islands of Hunga Tonga and Hunga Ha'apai are part of the western and northern remnants of the rim (~6 km diameter) of a largely submarine caldera located about 30 km SSE of Falcon Island. The topmost sequence of welded and unwelded ignimbrite units from a caldera-forming eruption was 14C dated to 1040-1180 CE (Cronin et al., 2017; Brenna et al. 2022). At least two additional welded pumice-rich ignimbrite units and nonwelded pyroclastic flow deposits, below paleosols and other volcaniclastic deposits, indicated more very large previous eruptions (Cronin et al., 2017; Brenna et al. 2022). Several submarine eruptions have occurred at this caldera system since the first recorded eruption in 1912, including 1937 and S of the islands in 1988. A short eruption in 2009 added land to to Hunga Ha'apai. At that time the two islands were each about 2 km long, displaying inward-facing sea cliffs with lava and tephra layers dipping gently away from the caldera. An eruption during December 2014-January 2015 was centered between the islands, and combined them into one larger structure. Major explosive eruptions in late 2021 initially reshaped the central part of the combined island before stronger activity in mid-January 2022 removed most of the 2014-15 material; an even larger eruption the next day sent an eruption plume high into the stratosphere, triggered shock waves through the atmosphere and tsunami across the Pacific Ocean, and left only small remnants of the islands above the ocean surface. Source: Tonga Geological Services, Government of Tonga https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7bQpsWw$ <https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw8Wf4WG8$> Krakatau | Sunda Strait | 6.102°S, 105.423°E | Summit elev. 155 m PVMBG reported that as many as 10 eruptive events at Anak Krakatau were recorded during 3-5 February, with dense, gray-black ash plumes rising 800-1,000 m above the vent and drifting N, NE, E, and S. Ash emissions were first visible at 1000 on 3 February, and incandescence above the crater was observed at night. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the crater. Geologic Summary. The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of this ancestral volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption, the 2nd largest in Indonesia during historical time, caused more than 36,000 fatalities, most as a result of devastating tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIii16zoI$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwa92JAxc$> Taal | Luzon (Philippines) | 14.002°N, 120.993°E | Summit elev. 311 m PHIVOLCS reported that unrest at Taal continued during 1-8 February, with persistent low-level background tremor, hot volcanic fluids circulating in the crater lake, and daily gas-and-steam plumes rising as high as 1.5 km above the lake that drifted SW. Sulfur dioxide emissions continued to be elevated, averaging 7,008-7,902 tonnes/day on 2 and 4 February. Each day during 1-3 February the seismic network recorded as many as 152 volcanic earthquakes, 114 low-frequency volcanic earthquakes per day, five hybrid events, and 33 daily episodes of volcanic tremor each lasting 1-2 minutes. One short-lived (two minutes) phreatomagmatic burst recorded at 1555 on 2 February produced a plume that rose 300 m from the lake and drifted SW. Two low-frequency earthquakes were noted during 3-4 February and one volcanic earthquake was recorded during 7-8 February. Tilt, continuous GPS, and InSAR data all indicated that Taal Volcano Island and the Taal region had begun deflating in October 2021. The Volcano Alert Level remained at a 2 (on a scale of 0-5). PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and warned against extended stays on Taal Lake. Geologic Summary. Taal is one of the most active volcanoes in the Philippines and has produced some of its most powerful historical eruptions. Though not topographically prominent, its prehistorical eruptions have greatly changed the landscape of SW Luzon. 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, and several eruptive centers lie submerged beneath the lake. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all historical eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones that have grown about 25% in area during historical time. Powerful pyroclastic flows and surges from historical eruptions have caused many fatalities. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIAZsryk0$ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwmpgtLFo$> Villarrica | Central Chile | 39.42°S, 71.93°W | Summit elev. 2847 m The Buenos Aires VAAC reported that an ash plume from Villarrica rose 2.7-4.6 km (9,000-15,000 ft) a.s.l. and drifted E at 1050 on 2 February based on webcam images and information from SERNAGEOMIN. By 1130 the ash plume was barely visible in satellite images. Webcam images showed continuous emissions of gas with sporadic puffs of ash that rose as high as 4.9 km (16,000 ft) a.s.l. The puffs of ash were diffuse by 1730, and by 2330 no emissions were visible in webcam and satellite images. Geologic Summary. Glacier-clad Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A 2-km-wide caldera that formed about 3500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesitic cone at the NW margin of the Pleistocene caldera. More than 30 scoria cones and fissure vents dot the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano were produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Historical eruptions, documented since 1558, have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged towns on its flanks. Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) https://urldefense.com/v3/__http://www.smn.gov.ar/vaac/buenosaires/productos.php__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIRndUNzE$ <https://urldefense.com/v3/__http://www.smn.gov.ar/vaac/buenosaires/productos.php__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwhmBqv24$> Wolf | Isla Isabela (Galapagos) | 0.02°N, 91.35°W | Summit elev. 1710 m IG reported that the eruption at Wolf continued during 1-8 February. Daily thermal alert counts, anywhere from a few to well over two hundred, indicated active and advancing lava flows on the SE flank. Gas emissions were identified in satellite images on most days. Geologic Summary. Wolf, the highest volcano of the Galápagos Islands, straddles the equator at the north end of the archipelago's largest island, Isabela. The 1710-m-high edifice has steeper slopes than most other Isabela volcanoes, reaching angles up to 35 degrees. A 6 x 7 km caldera, at 700 m one of the deepest of the Galápagos Islands, is located at the summit. A prominent bench on the west side of the caldera rises 450 above the caldera floor, much of which is covered by a lava flow erupted in 1982. Radial fissures concentrated along diffuse rift zones extend down the north, NW, and SE flanks, and submarine vents lie beyond the north and NW fissures. Similar unvegetated flows originating from a circumferential chain of spatter and scoria cones on the eastern caldera rim drape the forested flanks to the sea. The proportion of aa lava flows at Volcán Wolf exceeds that of other Galápagos volcanoes. An eruption in in 1797 was the first documented historical eruption in the Galápagos Islands. Source: Instituto GeofÃsico-Escuela Politécnica Nacional (IG) https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI4zb0hIQ$ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw0-RW__w$> Ongoing Activity Aira | Kyushu (Japan) | 31.593°N, 130.657°E | Summit elev. 1117 m JMA reported that very small eruptive events were recorded at Minamidake Crater (at Aira Calderaâ??s Sakurajima volcano) during 31 January-4 February. Ejected incandescent material was visible at night during 4-7 February. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater. Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIwhGY79E$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwsKxzB88$> Ambae | Vanuatu | 15.389°S, 167.835°E | Summit elev. 1496 m On 5 February the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that the cone in Ambaeâ??s Lake Voui continued to grow and produce steam, gas, and ash emissions. Images from two webcams (in Saratamata, Ambae Island and in Enar, Pentecost Island) showed the plumes rising above the summit and drifting S and SE. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone defined as a 2-km radius around the active vents in Lake Voui and away from drainages during heavy rains. Geologic Summary. The island of Ambae, also known as Aoba, is a massive 2,500 km3 basaltic shield that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW-trending rift zone dotted with scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and Manaro Lakua) is located at the summit within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. That large central edifice is also called Manaro Voui or Lombenben volcano. Post-caldera explosive eruptions formed the summit craters about 360 years ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast. Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD) https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7d0thpY$ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwm_X5l_0$> Davidof | Aleutian Islands (USA) | 51.97°N, 178.33°E | Summit elev. 328 m An earthquake swarm, either related to tectonic processes or volcanic unrest, began in the vicinity of Davidof on 24 January. The swarm continued at low levels during 1-8 February with daily small earthquakes. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory. Geologic Summary. A cluster of small islands between Segula and Little Sitkin in the western Aleutians, the largest of which is Davidof, are remnants of a stratovolcano that collapsed during the late Tertiary, forming a 2.7-km-wide caldera. The islands include Khvostof, Pyramid, Lopy, and Davidof; the latter three form the eastern rim of the mostly submarine caldera, sometimes referred to as the "Aleutian Krakatau." The islands were constructed above a roughly 100-m-deep submarine platform extending NW to Segula Island; the floor of the caldera lies 80 m below sea level. The islands are vegetated, but lava flows are recognizable, and Smith et al. (1978) suggested a possible Holocene age. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$> Etna | Sicily (Italy) | 37.748°N, 14.999°E | Summit elev. 3320 m INGV reported that sporadic explosive activity at Etnaâ??s Southeast Crater (SEC) resumed at 0115 on 30 January, producing diffuse ash emissions that rapidly dispersed near the summit, and weak Strombolian activity was visible the next day. Webcam views were intermittent due to weather clouds the next day, but by the morning of 2 February all activity had definitely stopped. Minor and variable gas emissions rose from the Northeast Crater, Bocca Nuova, and Voragine Crater. Geologic Summary. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank. Source: Sezione di Catania - Osservatorio Etneo (INGV) https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIvXiAAik$ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwZboak1w$> Great Sitkin | Andreanof Islands (USA) | 52.076°N, 176.13°W | Summit elev. 1740 m AVO reported that slow lava effusion at Great Sitkin continued during 2-8 February, though cloudy conditions often prevented satellite and webcam views. Seismicity remained slightly elevated. The flow field expanded with up to 100 m of advancement of the S, W, and N flank lava flows. Elevated surface temperatures were periodically identified in satellite images. A steam plume was visible in webcam images during 5-6 February. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively. Geologic Summary. The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger parasitic volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an ancestral volcano and produced a submarine debris avalanche. Deposits from this and an older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Historical eruptions have been recorded since the late-19th century. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$> Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m HVO reported that lava effusion at the vent of the main cone in the lower W wall of Kilaueaâ??s Halema`uma`u Crater continued during 2-8 February. The lake level fluctuated, likely reflecting variable lava supply along with periods of inflation and deflation. A small spatter cone, less than 6 m tall, located near the E end of the crater produced lava fountains that were 10 m tall in the evening of 1 February. The fountains fed a short flow confined to the E margin of the crater. Effusion from the W vent paused during around 0900-1730 on 2 February. During the rest of the week the effusion rate fluctuated; the lake continued to circulate, although less when the effusion rate was lower. Multiple ooze-outs of lava along the N, E, and S margins of the crater were visible. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively. Geologic Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIBKuB8zI$ <https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwbKH96k4$> Lewotolok | Lembata Island | 8.274°S, 123.508°E | Summit elev. 1431 m PVMBG reported that the eruption at Lewotolok continued during 1-7 February, though weather conditions sometimes prevented visual confirmation. Rumbling and weak banging noises were heard throughout the week. Crater incandescence from active lava effusion was periodically observed. White, gray, and black ash plumes rose 100-400 m above the summit during 3-4 and 6-8 February. Incandescent material was ejected 300 m SE during 7-8 February. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater and 4 km away from the crater on the SE flank. Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIii16zoI$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwa92JAxc$> Merapi | Central Java | 7.54°S, 110.446°E | Summit elev. 2910 m BPPTKG reported no significant morphological changes at Merapiâ??s lava domes, located just below the SW rim and in the summit crater, during 28 January-3 February. Seismicity remained at high levels and earthquakes were more intense than the previous week. In the SW-flank Bebeng drainage there were as many as 133 lava avalanches that traveled a maximum of 2 km and two pyroclastic flows that extended 2-2.5 km; one lava avalanche also went 300 m NW. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-5 km away from the summit based on location. Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIdbuDimE$ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwywfS2bg$> Pavlof | Alaska Peninsula, Alaska | 55.417°N, 161.894°W | Summit elev. 2493 m AVO reported that the eruption at Pavlof was ongoing during 1-8 February with lava effusion on the upper SE flank feeding a branching flow on the E flank. Seismicity was elevated with periods of tremor and elevated surface temperatures were identified in satellite images; both were consistent was continuing lava effusion. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. Geologic Summary. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$> Popocatepetl | Mexico | 19.023°N, 98.622°W | Summit elev. 5393 m CENAPRED reported that each day during 1-8 February there were 25-77 steam-and-gas emissions with diffuse ash rising from Popocatépetl and drifting ENE. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale). Geologic Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time. Source: Centro Nacional de Prevencion de Desastres (CENAPRED) https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdInUlk4OY$ <https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwp2dNwF4$> Rincon de la Vieja | Costa Rica | 10.83°N, 85.324°W | Summit elev. 1916 m OVSICORI-UNA reported that an eruption at Rincón de la Vieja was recorded at 1853 on 2 February. No plumes were visible due to weather conditions. Geologic Summary. Rincón de la Vieja, the largest volcano in NW Costa Rica, is a remote volcanic complex in the Guanacaste Range. The volcano consists of an elongated, arcuate NW-SE-trending ridge constructed within the 15-km-wide early Pleistocene GuachipelÃn caldera, whose rim is exposed on the south side. Sometimes known as the "Colossus of Guanacaste," it has an estimated volume of 130 km3 and contains at least nine major eruptive centers. Activity has migrated to the SE, where the youngest-looking craters are located. The twin cone of Santa MarÃa volcano, the highest peak of the complex, is located at the eastern end of a smaller, 5-km-wide caldera and has a 500-m-wide crater. A Plinian eruption producing the 0.25 km3 RÃo Blanca tephra about 3,500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous historical eruptions possibly dating back to the 16th century, have been from the prominent active crater containing a 500-m-wide acid lake located ENE of Von Seebach crater. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI5yyGjUc$ <https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwAvYzhI4$> Sangay | Ecuador | 2.005°S, 78.341°W | Summit elev. 5286 m IG reported a high level of activity at Sangay during 2-7 February, and seismicity was characterized by daily explosions, long-period earthquakes, and signals indicating emissions. Weather clouds and rain often prevented visual and webcam observations of the volcano, though almost daily ash-and-gas plumes were identified in satellite images by the Washington VAAC or in webcam views; plumes rose as high as 1.5 km above the volcano and drifted in multiple directions. Multiple daily thermal anomalies over the volcano were visible in satellite data. Several ash emissions were observed in satellite images on 8February; at 0430 an ash plume rose more than 7 km above the summit, the highest a plume had risen since the current eruption started in 2019. Ashfall was reported in areas to the NW, in the provinces of Chimborazo and Bolivar. Geologic Summary. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of a historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex. Source: Instituto GeofÃsico-Escuela Politécnica Nacional (IG) https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI4zb0hIQ$ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw0-RW__w$> Santa Maria | Southwestern Guatemala | 14.757°N, 91.552°W | Summit elev. 3745 m INSIVUMEH reported that activity at Santa MarÃaâ??s Santiaguito lava-dome complex had increased on 29 January and remained elevated. Block-and-ash flows on 3 February descended the W and SW flanks and generated ash clouds that rose 600-800 m high and drifted W and NW. Ashfall was reported in San Martin Sacatepéquez (11 km NW), Llanos del Pinal (6 km NNE), Xecaracoj (7 km NNE), Loma Linda (6 km WSW), and El Palmar (12 km SSW), all in the department of Quetzaltenango. The report noted that during 30 January-3 February a total of 20 pyroclastic flows had traveled 1-3 km down the San Isidro drainage. Block-and-ash flows descended the W, SW, and NE flanks during 3-4 February. A lahar descended the San Isidro River, a SSW-flank tributary of the Tambor River, on 8 February. 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 W 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. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIMspNHKo$ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw9FQtYqQ$> ; Coordinadora Nacional para la Reducción de Desastres (CONRED) https://urldefense.com/v3/__http://conred.gob.gt/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdINpQMhzI$ <https://urldefense.com/v3/__http://conred.gob.gt/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwwJSm2pY$> Semeru | Eastern Java | 8.108°S, 112.922°E | Summit elev. 3657 m PVMBG reported that the eruption at Semeru continued during 1-8 February, though weather conditions often prevented visual confirmation. Crater incandescence was visible during 1-2 and 7-8 February. White steam-and-gas plumes rose as high as 1.2 km above the crater rim during 2-3 February. Eruptive events produced gray-to-white ash plumes that rose 300-700 m during 2-4 and 7-8 February. The active lava flow on the SE flank was 3.5 km long; avalanches from the end of the flow traveled 100-200 m down the drainage during 7-8 February. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards. Geologic Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIii16zoI$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwa92JAxc$> Semisopochnoi | Aleutian Islands (USA) | 51.93°N, 179.58°E | Summit elev. 1221 m AVO reported that low-level eruptive activity at Semisopochnoi's North Cerberus cone continued during 1-8 February. Seismicity was elevated, and explosions were occasionally detected in both seismic and infrasound data during 4-8 February. Steam and low-level ash emissions likely occurred daily, though due to weather clouds they were only confirmed in satellite and webcam images during 1-2 and 5-8 February. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch. Geologic Summary. Semisopochnoi, the largest subaerial volcano of the western Aleutians, is 20 km wide at sea level and contains an 8-km-wide caldera. It formed as a result of collapse of a low-angle, dominantly basaltic volcano following the eruption of a large volume of dacitic pumice. The high point of the island is Anvil Peak, a double-peaked late-Pleistocene cone that forms much of the island's northern part. The three-peaked Mount Cerberus was constructed within the caldera during the Holocene. Each of the peaks contains a summit crater; lava flows on the N flank of Cerberus appear younger than those on the south side. Other post-caldera volcanoes include the symmetrical Sugarloaf Peak SSE of the caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake in the NE part of the caldera. Most documented eruptions have originated from Cerberus, although Coats (1950) considered that both Sugarloaf and Lakeshore Cone could have been recently active. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$> Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 28 January-4 February. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7-3vz34$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwIUtd3Qg$> Suwanosejima | Ryukyu Islands (Japan) | 29.638°N, 129.714°E | Summit elev. 796 m JMA reported that volcanic plumes from Suwanosejima's Ontake Crater rose as high as 2.2 km above the crater rim during 31 January-7 February. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater. Geologic Summary. The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIwhGY79E$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwsKxzB88$> Turrialba | Costa Rica | 10.025°N, 83.767°W | Summit elev. 3340 m OVSICORI-UNA reported that at 1259 on 6 February a small phreatic eruption at Turrialbaâ??s Cráter Oeste produced an ash plume that rose 100 m above the crater rim. A thermal anomaly from the floor of Cráter Oeste was identified in satellite images on 4 February. The anomaly was last seen in the same location on 25 January, and twice in 2021, during clear weather conditions; the location of the anomaly was the same in those images since March 2021, and likely represented a hot crack venting on the crater floor. Two incandescent points in the crater were visible in overnight webcam images during 7-8 February. Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI5yyGjUc$ <https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwAvYzhI4$> Yasur | Vanuatu | 19.532°S, 169.447°E | Summit elev. 361 m On 2 February the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that sulfur dioxide gas emissions from Yasurâ??s active lava lake were detected drifting NW in satellite images. The Alert Level remained at 2 (on a scale of 0-4) and the public was reminded not to enter the restricted area within 600 m around the cone, defined by Danger Zone A on the hazard map. Geologic Summary. Yasur, the best-known and most frequently visited of the Vanuatu volcanoes, has been in more-or-less continuous Strombolian and Vulcanian activity since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island, this mostly unvegetated pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide, horseshoe-shaped caldera associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century. Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD) https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7d0thpY$ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwm_X5l_0$> 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). 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