1-1-1-1-1-1-1-1-1-1-1-1-1-1 From: "Bennis, Kadie" <BennisK@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 27 July-2 August 2022 Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgRTwIWtK$ <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldsiXcVGvQ$> *New Activity/Unrest: *Aira, Kyushu (Japan) | Askja, Iceland | Ioto, Volcano Islands | Krysuvik-Trolladyngja, Reykjanes Peninsula | Kuchinoerabujima, Ryukyu Islands (Japan) | Raung, Eastern Java *Ongoing Activity:* Ebeko, Paramushir Island (Russia) | Great Sitkin, Andreanof Islands (USA) | Grimsvotn, Iceland | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Krakatau, Sunda Strait | Merapi, Central Java | Pavlof, Alaska Peninsula, Alaska | Semeru, Eastern Java | Sheveluch, Central Kamchatka (Russia) | Suwanosejima, Ryukyu Islands (Japan) | Yufu-Tsurumi, Kyushu (Japan) 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* *Aira* | Kyushu (Japan) | 31.593°N, 130.657°E | Summit elev. 1117 m JMA lowered the Alert Level for Aira Calderaâ??s Sakurajima volcano to 3 (on a 5-level scale) on 27 July, noting that after the larger eruption on 24 July material had not been ejected more than 2 km from the crater; residents were warned to stay 2 km away from the crater. During 25 July-1 August the seismic network recorded about 11 explosions and 19 eruptive events, producing plumes that rose as high as 2.2 km above the summit and ejected material far as 1.1 km. Crater incandescence was visible nightly. No deformation was detected. 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!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgYFWtOQU$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvQydncpw$> *Askja* | Iceland | 65.033°N, 16.783°W | Summit elev. 1080 m On 27 July IMO stated that uplift at Askja began in August 2021 and since then had totaled 35 cm, centered in the W part of Askja lake. The uplift was rapid, compared to similar volcanoes around the world, and likely caused by a magmatic intrusion at an estimated depth of 2 km. Seismicity remained low. Geologic Summary. Askja is a large basaltic central volcano that forms the Dyngjufjöll massif. It is truncated by three overlapping calderas, the largest of which is 8 km wide and may have been produced primarily from subglacial ring-fracture eruptions rather than by subsidence. A major rhyolitic explosive eruption from Dyngjufjöll about 10,000 years ago was in part associated with the formation of Askja caldera. Many postglacial eruptions also occurred along the ring-fracture. A major explosive eruption on the SE caldera margin in 1875 was one of Iceland's largest during historical time. It resulted in the formation of a smaller 4.5-km-wide caldera, now filled by Ã?skjuvatn lake, that truncates the rim of the larger central caldera. The 100-km-long Askja fissure swarm, which includes the Sveinagja graben, is also related to the Askja volcanic system, as are several small shield volcanoes such as Kollatadyngja. Twentieth-century eruptions have produced lava flows from vents located mostly near Ã?skjuvatn lake. Source: Icelandic Meteorological Office (IMO) https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgbfpNcIR$ <https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldsteRilHw$> *Ioto* | Volcano Islands | 24.751°N, 141.289°E | Summit elev. 169 m Satellite images of Ioto (Iwo-jima) acquired on 15 July showed a darker area in the water along the SE coast, possibly above or near the 2001 vent, and a plume of discolored water drifting NE. Video taken on or around 25 July showed a white plume rising from the same area. Satellite images during 30-31 July showed small rounded gray zones at the water surface. Geologic Summary. Ioto in the central Volcano Islands portion of the Izu-Marianas arc lies within a 9-km-wide submarine caldera. Ioto, Iwojima, and Iojima are among many transliterations of the name. The volcano is also known as Ogasawara-Iojima to distinguish it from several other "Sulfur Island" volcanoes in Japan. The triangular, low-elevation, 8-km-long island narrows toward its SW tip and has produced trachyandesitic and trachytic rocks that are more alkalic than those of other Izu-Marianas arc volcanoes. The island has undergone dramatic uplift for at least the past 700 years accompanying resurgent doming of the caldera. A shoreline landed upon by Captain Cook's surveying crew in 1779 is now 40 m above sea level. The Motoyama plateau on the NE half of the island consists of submarine tuffs overlain by coral deposits and forms the island's high point. Many fumaroles are oriented along a NE-SW zone cutting through Motoyama. Numerous historical phreatic eruptions, many from vents on the west and NW sides of the island, have accompanied the remarkable uplift. Sources: Sentinel Hub https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgZ99_-m-$ <https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOlduNK9XPiQ$> ; Planet Labs https://urldefense.com/v3/__https://www.planet.com/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgZ_hYcqd$ <https://urldefense.com/v3/__https://www.planet.com/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldtiM8_7Sw$> *Krysuvik-Trolladyngja* | Reykjanes Peninsula | 63.917°N, 22.067°W | Summit elev. 360 m Icelandic Meteorological Office (IMO) reported that an intense earthquake swarm began around noon on 30 July within the KrýsuvÃk-Trölladyngja volcanic system. The earthquakes were located in an area just NE of lava field in Geldingadalir, along the dike intrusion that preceded the March-September 2021 eruption. The swarm was likely caused by a magmatic intrusion at depths of 5-7 km. Earthquakes were reportedly felt in SW Iceland, in Reykjanesbær, GrindavÃk, the Capital region, and as far as Borgarnes. Several earthquakes were above M 3; a larger M 4 event was recorded at 1403. IMO raised the Aviation Color Code to Yellow, based on above-background seismic levels. At around 1800 the epicenters shallowed to depths of 2-5 km. By 1527 on 31 July almost 3,000 earthquakes had been detected, with four of the events larger than an M 4. A larger M 5.4 earthquake was detected at 1748. IMO reported at 1749 on 2 August that deformation models indicated magma around 1 km below the surface. The intrusion rate was close to double that recorded prior to the 2021 eruption, though by the reporting time the intrusion and seismicity rates had slowed. IMO noted that a similar pattern of events took place prior to the last eruption and stated that the likelihood of an eruption had increased. An effusive eruption began at 1315 on 3 August in Meradalir, near the border of the previous flow field N of Fagradalsfjall. Webcam video showed lava fountains rising along a 300-m-long fissure. As a result, IMO raised the Aviation Color Code to Orange at 1536. Gas-and-steam plumes rose 500-1,000 m high, but no ash was detected. Geologic Summary. The KrýsuvÃk-Trölladyngja volcanic system is described by the Catalogue of Icelandic Volcanoes as an approximately 50-km-long composite fissure swarm trending about N38°E, including a 30-km-long swarm of fissures, with no central volcano. It is one of the volcanic systems arranged en-echelon along the Reykjanes Peninsula west of Kleifarvatn lake. The Fagradalsfjall and KrýsuvÃk fissure swarms are considered splits or secondary swarms of the KrýsuvÃkâ??Trölladyngja volcanic system. Small shield volcanoes have produced a large portion of the erupted volume within the system. Several eruptions have taken place since the settlement of Iceland, including the eruption of a large basaltic lava flow from the Ogmundargigar crater row around the 12th century. The latest eruption, identified through tephrochronology, took place during the 14th century. Source: Icelandic Meteorological Office (IMO) https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgbfpNcIR$ <https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldsteRilHw$> *Kuchinoerabujima* | Ryukyu Islands (Japan) | 30.443°N, 130.217°E | Summit elev. 657 m JMA reported that the number of volcanic earthquakes with hypocenters near Kuchinoerabujimaâ??s crater began increasing around 1000 on 30 July and remained elevated. The Alert level was raised to 2 (on a scale of 1-5) on 31 July. Around 40 volcanic earthquakes were recorded by 1500 on 1 August. JMA noted that daily emissions of sulfur dioxide gas remained low, with a rate less than 50 tons per day. No deformation was detected. Geologic Summary. A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km W of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. All historical eruptions have occurred from Shindake, although a lava flow from the S flank of Furudake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shindake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgYFWtOQU$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvQydncpw$> *Raung* | Eastern Java | 8.119°S, 114.056°E | Summit elev. 3260 m According to PVMBG an eruption at Raung at 1719 on 27 July produced a gray ash plume that rose 1-1.5 km above the summit and drifted W and NW. On 28 July a thermal anomaly in the crater was identified in satellite images and data from the GPS network indicated inflation, likely from an intrusion of magma. Seismicity on 29 July was dominated by continuous tremor. The Alert Level was raised to 2 (on a scale of 1-4) that same day, and the public was warned to stay 3 km away from the crater. Geologic Summary. Raung, one of Java's most active volcanoes, is a massive stratovolcano in easternmost Java that was constructed SW of the rim of Ijen caldera. The unvegetated summit is truncated by a dramatic steep-walled, 2-km-wide caldera that has been the site of frequent historical eruptions. A prehistoric collapse of Gunung Gadung on the W flank produced a large debris avalanche that traveled 79 km, reaching nearly to the Indian Ocean. Raung contains several centers constructed along a NE-SW line, with Gunung Suket and Gunung Gadung stratovolcanoes being located to the NE and W, respectively. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgVhCgZrQ$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvpTUbuKw$> *Ongoing Activity* *Ebeko* | Paramushir Island (Russia) | 50.686°N, 156.014°E | Summit elev. 1103 m KVERT reported that moderate activity at Ebeko was ongoing during 21-28 July. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions generated ash plumes that rose up to 4 km (13,100 ft) a.s.l. and drifted in multiple directions. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgX-kOG8h$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvKshh_7g$> *Great Sitkin* | Andreanof Islands (USA) | 52.076°N, 176.13°W | Summit elev. 1740 m AVO reported that slow lava effusion at Great Sitkin continued during 26 July-2 August. Weather clouds obscured satellite and webcam views during most of the week, though satellite radar data confirmed ongoing effusion; flows thickened but did not advance. Seismicity was low, and occasional local earthquakes were recorded. Steam emissions were visible in satellite and webcam images during 29-30 July. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively. Geologic Summary. The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger parasitic volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an ancestral volcano and produced a submarine debris avalanche. Deposits from this and an older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Historical eruptions have been recorded since the late-19th century. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgVdFcqYg$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOlduljRVUGg$> *Grimsvotn* | Iceland | 64.416°N, 17.316°W | Summit elev. 1719 m The Icelandic Meteorological Office (IMO) reported that increased seismicity, characterized by several earthquakes with magnitudes over 1, began at GrÃmsvötn during the afternoon of 2 August and continued through the afternoon of 3 August. The largest event was a M 3.6 detected at 1424. IMO raised the Aviation Color Code to Yellow. Geologic Summary. GrÃmsvötn, Iceland's most frequently active volcano in recent history, lies largely beneath the vast Vatnajökull icecap. The caldera lake is covered by a 200-m-thick ice shelf, and only the southern rim of the 6 x 8 km caldera is exposed. The geothermal area in the caldera causes frequent jökulhlaups (glacier outburst floods) when melting raises the water level high enough to lift its ice dam. Long NE-SW-trending fissure systems extend from the central volcano. The most prominent of these is the noted Laki (Skaftar) fissure, which extends to the SW and produced the world's largest known historical lava flow in 1783. The 15 km3 basaltic Laki lavas were erupted over a 7-month period from a 27-km-long fissure system. Extensive crop damage and livestock losses caused a severe famine that resulted in the loss of one-fifth of the population of Iceland. Source: Icelandic Meteorological Office (IMO) https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgbfpNcIR$ <https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldsteRilHw$> *Karymsky* | Eastern Kamchatka (Russia) | 54.049°N, 159.443°E | Summit elev. 1513 m KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 21-23 and 27-28 July. Ash plumes were identified in satellite images drifting 46 km ESE on 27 July. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgX-kOG8h$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvKshh_7g$> *Kilauea* | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m HVO reported that lava continued to effuse from a vent in the lower W wall of Kilaueaâ??s Halema`uma`u Crater during 26 July-2 August, entering the lava lake and flowing onto the crater floor. Minor ooze-outs along the margins of the crater floor were visible during 1-2 August. The lake level remained at the bounding levees. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively. Geologic Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92Vgf7k8imh$ <https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldsatHbDaw$> *Krakatau* | Sunda Strait | 6.102°S, 105.423°E | Summit elev. 155 m PVMBG reported that the eruption at Anak Krakatau continued during 27 July-2 August. Several eruptive events occurred on 2 August (at 1549, 1835, 1906, 2249, and 2319) and on 3 August (at 0034, 0115, and 1540), sometimes producing black ash plumes that rose as high as 1.5 km above the summit and drifted NE and SW. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay at least 5 km away from the crater. Geologic Summary. The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of that volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption caused more than 36,000 fatalities, most as a result of tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgVhCgZrQ$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvpTUbuKw$> *Merapi* | Central Java | 7.54°S, 110.446°E | Summit elev. 2910 m BPPTKG reported that the eruption at Merapi continued during 22-28 July. Based on photo analyses, the volumes of both the SW and central lava domes had increased, with recent volume estimates of 1.67 and 2.79 million cubic meters, respectively. Seismicity remained at high levels. As many as 47 lava avalanches traveled down the Bebeng drainage on the SW flank, reaching a maximum distance of 1.8 km. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit based on location. Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgbzU7lXu$ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldt5jn9oPg$> *Pavlof* | Alaska Peninsula, Alaska | 55.417°N, 161.894°W | Summit elev. 2493 m AVO reported that a minor eruption at a vent on Pavlofâ??s upper E flank was ongoing during 26 July-2 August. Daily elevated surface temperatures were identified in satellite images. Seismic tremor persisted and multiple daily explosions were detected in local and regional seismic and infrasound data. The explosions likely produced minor ash emissions that rose no higher than 3 km (10,000 ft) a.s.l., though cloud cover prevented confirmation on most days. Ash emissions were visible in webcam images during 27-28 July. Sulfur dioxide gas emissions were visible on 26 July and team emissions were noted during 30-31 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. Geologic Summary. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgVdFcqYg$ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOlduljRVUGg$> *Semeru* | Eastern Java | 8.108°S, 112.922°E | Summit elev. 3657 m PVMBG reported that the eruption at Semeru continued during 27 July-2 August. Eruptive events recorded at 0637 on 27 July, 0926 on 29 July, 0825 on 31 July, 0757 on 1 August, 0555 on 2 August, and 0810 on 3 August produced ash plumes that rose 500-700 m above the summit and drifted SW. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 5 km away from the summit, and 500 m from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards. Geologic Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgVhCgZrQ$ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvpTUbuKw$> *Sheveluch* | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m KVERT reported that the ongoing eruption at Sheveluch was characterized by explosions, hot avalanches, and lava-dome extrusion during 21-28 July. A daily thermal anomaly was identified in satellite images, and ash plumes were visible drifting 74 km SSW and SE on 22 and 24 July. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgX-kOG8h$ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvKshh_7g$> *Suwanosejima* | Ryukyu Islands (Japan) | 29.638°N, 129.714°E | Summit elev. 796 m JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 25 July-2 August. One explosion produced an eruption plume that rose more than 1.8 km above the crater rim and caused ashfall in Toshima village (3.5 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater. Geologic Summary. The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgYFWtOQU$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvQydncpw$> *Yufu-Tsurumi* | Kyushu (Japan) | 33.282°N, 131.39°E | Summit elev. 1584 m JMA lowered the Alert Level for Yufu-Tsurumi to 1 (on a scale of 1-5) on 27 July, noting that seismicity had decreased after the 8 July earthquake swarm; no volcanic earthquakes were recorded on 9 July and afterwards. Geologic Summary. A group of lava domes rises above the noted hot spring resort city of Beppu on Japan's Inland Sea, possibly within an ancient breached caldera. Two large lava domes, Tsurumidake and Yufudake (the highest at 1,584 m), are located at the east and west sides of the complex, respectively. Three smaller lava domes are on the N flank of Tsurumidake, including Garandake. The latest activity at both the andesitic-to-dacitic Tsurumi and Yufu groups postdates the 6300-year-old Akahoya ash from Kikai volcano. Pyroclastic flows dominated during older eruptions, whereas lava domes and lava flows are most common in more recent eruptions. An eruption about 2200 years ago from Yufudake began with collapse of the N flank that produced a debris avalanche and was followed by lava dome growth and associated pyroclastic flows. Only a single eruption, from Tsurumi in 867 CE, is known in historical time. The colorful hot spring pools and mudpots of Beppu along the coast form one of Japan's most noted thermal areas. Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!fFo39LYp8ud6wjTWF0lB0PK8DavNO7XHN3vgjsIVCVm8D9cpdYN_ULz7zJANQTsZVXDOk92VgYFWtOQU$ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cAaBq2w_zJTKMUkt7lhrLFzppFgzTd6bjAekiAvq-tPiNofP6IN2LsfnC29exTuXGtqOldvQydncpw$> 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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