3-3-3-3-3-3-3-3-3-3-3-3-3 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 17-23 September 2025 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFoLaHstXw$> New Activity/Unrest: Akan, Japan | Bur ni Telong, Indonesia | Kanlaon, Philippines | Lokon-Empung, Indonesia | Rincon de la Vieja, Costa Rica | Sabancaya, Peru Ongoing Activity: Aira, Japan | Bezymianny, Russia | Dukono, Indonesia | Fuego, Guatemala | Great Sitkin, United States | Ibu, Indonesia | Karymsky, Russia | Katmai, United States | Kilauea, United States | Klyuchevskoy, Russia | Krasheninnikov, Russia | Kuchinoerabujima, Japan | Lewotobi, Indonesia | Lewotolok, Indonesia | Marapi, Indonesia | Merapi, Indonesia | Nyamulagira, DR Congo | Popocatepetl, Mexico | Santa Maria, Guatemala | Semeru, Indonesia | Sheveluch, Russia | Stromboli, Italy | Suwanosejima, 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 Akan | Japan | 43.384°N, 144.013°E | Summit elev. 1499 m The Japan Meteorological Agency (JMA) reported eruptive activity at Me-Akan (also known as Meakan-dake, which means Meakan Peak) of the Akan volcanic complex during 16-23 September. Seismicity near Ponmachineshiri Crater that increased on 11 September continued to fluctuate at elevated levels. The seismic network recorded 27-50 daily volcanic earthquakes. Tilt in the direction of the crater continued at a low rate. Minor ashfall around the crater was visible on 16 September. During 17-23 September the volume of white steam-and-gas plumes rising from 96-1 Crater within Ponmachineshiri continued to be high; the plumes rose 200-800 m above the crater rim and drifting E and SE. The Alert Level remained at 2 (the second lowest level on a 5-level scale) and the public was warned to exercise caution within 500 m of Ponmachineshiri Crater. Geologic Summary. Akan is a 13 x 24 km caldera located immediately SW of Kussharo caldera in eastern Hokkaido. The elongated, irregular outline of the caldera rim reflects its incremental formation during major explosive eruptions from the early to mid-Pleistocene. There are four post-caldera stratovolcanoes, three at the SW end of the caldera and the other on the NE side. Conical Oakandake was frequently active during the Holocene. The 1-km-wide Nakamachineshiri crater of Meakandake was formed during a major pumice-and-scoria eruption about 13,500 years ago. The Meakandake group, composed of nine overlapping cones E of Lake Akan, has produced mild phreatic eruptions since the beginning of the 19th century. The main cone of Meakandake proper has a triple crater at its summit. Although recorded eruptions at Meakandake have consisted of minor phreatic explosions, four major magmatic eruptions with pyroclastic flows have also occurred during the Holocene. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrh4VZhXQ$> Bur ni Telong | Indonesia | 4.769°N, 96.821°E | Summit elev. 2617 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported increased unrest at Bur ni Telong. The number of deep volcanic earthquakes increased on 10, 15, and 22 September. Additionally, earthquakes with magnitudes of 2-3 were recorded by the seismic network and felt in several locations around the volcano. The Alert Level was raised to 2 (on a scale from 1 to 4) at 2100 on 22 September. The public was advised to maintain a minimum distance of 1.5 km from the crater area and to avoid the fumarole and solfatara regions, especially during cloudy or rainy weather. Geologic Summary. The conical Bur ni Telong volcano was constructed at the southern base of the massive Bur ni Geureudong volcanic complex, one of the largest in northern Sumatra. The historically active volcano lies 4.5 km from the summit of Geureudong,and its summit crater has migrated to the ESE, leaving arcuate crater rims. Lava flows are exposed on the southern flank. Explosive eruptions were recorded during the 19th and 20th centuries. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Kanlaon | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 16-23 September. The seismic network recorded 4-60 daily volcanic earthquakes. Gas-and-steam emissions of variable densities rose 75-600 m above the crater rim and drifted N, NE, and SE; views were obscured on 22 September. Sulfur dioxide emissions ranged from 797 to 1,996 tonnes per day. Two periods of ash emissions, lasting two and 69 minutes long, were visible on 17 September. The Alert Level remained at 2 (on a scale of 0-5); the public was warned to stay out of the 4-km-radius Permanent Danger Zone (PDZ) and pilots were advised to avoid flying close to the summit. Geologic Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFq8u1G0CA$> Lokon-Empung | Indonesia | 1.3644°N, 124.7992°E | Summit elev. 1580 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported continuing unrest at Lokon-Empung during 17-23 September. Daily white steam-and-gas plumes rose as high as 100 m above the Tompaluan Crater rim and drifted in multiple directions. Incandescence at the crater was visible on 17 September. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 2.5 km away from Tompaluan Crater. Geologic Summary. The Lokong-Empung volcanic complex, rising above the plain of Tondano in North Sulawesi, includes four peaks and an active crater. Lokon, the highest peak, has a flat craterless top. The morphologically younger Empung cone 2 km NE has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century. A ridge extending 3 km WNW from Lokon includes the Tatawiran and Tetempangan peaks. All eruptions since 1829 have originated from Tompaluan, a 150 x 250 m crater in the saddle between Lokon and Empung. These eruptions have primarily produced small-to-moderate ash plumes that sometimes damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Rincon de la Vieja | Costa Rica | 10.8314°N, 85.3364°W | Summit elev. 1729 m The Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that at 1944 on 21 September an eruption at Rincón de la Vieja ejected incandescent ballistics above the crater rim. The event was recorded in both infrasound and seismic data. Darkness obscured any plume. A small white plume was visible in webcam views during 22-23 September. Geologic Summary. Rincón de la Vieja is a volcanic complex in the Guanacaste Range of NW Costa Rica. Sometimes referred to as the Rincon de la Vieja-Santa MarÃa Volcanic Complex, it consists of a slightly arcuate 20-km-long ridge of 12 craters and pyroclastic cones constructed within the 15-km-wide early Pleistocene GuachipelÃn caldera, whose rim is exposed on the south side. Sometimes known as the "Colossus of Guanacaste," it has an estimated volume of 130 km3 and contains at least nine major eruptive centers. The Santa MarÃa cone, the highest peak of the complex, is located on the E side of the ridge and has a lake within the 400-m-diameter crater. A Plinian eruption producing the 0.25 km3 RÃo Blanca tephra about 3,500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous reported eruptions possibly dating back to the 16th century, have been from the active crater, near the center of the complex, with an acidic 300-m-diameter lake. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ <https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFpcnehZQw$> Sabancaya | Peru | 15.787°S, 71.857°W | Summit elev. 5960 m The Instituto GeofÃsico del Perúâ??s (IGP) Centro Vulcanológico Nacional (CENVUL) reported that daily gas-and-steam plumes at Sabancaya rose 500-1,600 m above the crater rim and drifted less than 10 km N, NE, and E during 17-22 September. Sulfur dioxide emissions were at low levels, averaging 131 tons per day. Thermal anomalies on the summit crater floor were detected during 20-21 September. The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay outside of a 12 km radius from the summit. Geologic Summary. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of observed eruptions date back to 1750 CE. Source: Instituto GeofÃsico del Perú (IGP) https://cenvul.igp.gob.pe/ <https://urldefense.com/v3/__https://cenvul.igp.gob.pe/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFpGlZFf8g$> Ongoing Activity Aira | Japan | 31.5772°N, 130.6589°E | Summit elev. 1117 m The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Calderaâ??s Sakurajima volcano) during 15-22 September. Nightly crater incandescence was visible in webcam images. Small eruptive events were occasionally recorded. Sulfur dioxide emissions were characterized as slightly high, averaging 1,700 tons per day on 19 September. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to be cautious within 2 km of both the Minimadake and Showa craters. Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim and built an island that was joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4,850 years ago, after which eruptions took place at Minamidake. Frequent eruptions since the 8th century have deposited ash on the city of Kagoshima, located across Kagoshima Bay only 8 km from the summit. The largest recorded eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrh4VZhXQ$> Bezymianny | Russia | 55.972°N, 160.595°E | Summit elev. 2882 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a thermal anomaly over Bezymianny was identified in satellite images during 12-13 and 17-18 September; weather clouds obscured views on the other days. According to the Tokyo VAAC re-suspended that was ash deposited during previous eruptions drifted SW on 17 September. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale). Dates are reported in UTC; specific events are in local time where noted. Geologic Summary. The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ <https://urldefense.com/v3/__http://kvert.febras.net/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFppxgoC1Q$> ; Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html <https://urldefense.com/v3/__http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrNiHcsqg$> Dukono | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 17-23 September. White-and-gray gas-and-ash plumes rose as high as 800 m above the summit on most days and drifted in multiple directions; plumes were not visible on 23 September. The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater. Geologic Summary. The Dukono complex in northern Halmahera is on an edifice with a broad, low profile containing multiple peaks and overlapping craters. Almost continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the Gunung Mamuya cone, 10 km NE. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also had reported eruptions. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Fuego | Guatemala | 14.4748°N, 90.8806°W | Summit elev. 3799 m The Instituto Nacional de SismologÃa, Vulcanologia, Meteorologia e HidrologÃa (INSIVUMEH) reported that eruptive activity at Fuego continued during 16-23 September. Daily Strombolian explosions were recorded by the seismic network at rates of 5-12 per hour. The explosions generated daily gas-and-ash plumes that rose as high as 1.1 km above the summit and drifted 10-30 km in multiple directions. Occasional rumbling sounds, shock waves, and/or sound associated with gas emissions were reported. Explosions ejected incandescent material 100-200 m above the summit during 16-17 and 21-22 September and showered the upper flanks with incandescent material during 21-22 September. Block avalanches descended the flanks, including the Las Lajas (SE), Seca (W), Taniluya (SSW), Trinidad (SSW), Santa Teresa (W), and Ceniza (SSW) drainages, sometimes reaching vegetated areas. Occasional ashfall was reported in areas downwind including Panimache I and II (8 km SW), Morelia (9 km SW), and Santa SofÃa (12 km SW) and local areas to the NE. Heavy rain generated lahars in multiple drainages during 17-19 September. Lahars descended the Ceniza, Zarco, and Mazate drainages based on a special report issued 1359 on 17 September, and the Seca and Mineral drainages based on a report issued at 1659 that same day. Special reports issued at 1430, 1445, and 1523 on 18 September noted that lahars descended the El Jute (ESE), Las Lajas, Ceniza, Zarco, Mazate, Seca, and Mineral (W) drainages. In the early afternoon on 19 September lahars descended the El Jute and Las Lajas drainages and the Ceniza, Zarco, and Mazate drainages based on reports issued at 1455 and 1505, respectively. Later that day hot lahars with a sulfur odor descended the El Jute and Las Lajas drainages, based on a report issued at 2010. All of the lahars were characterized as a mixture of water and sediment that carried tree branches, trunks, and blocks possibly as large as 3 m in diameter. Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFqLFOHpYQ$> Great Sitkin | United States | 52.076°N, 176.13°W | Summit elev. 1740 m The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkinâ??s summit crater during 16-23 September. Satellite data indicated that the SE part of the flow slightly inflated at a rate of about 5 meters of surface motion per day, though the distal margin of the flow did not advance. Small earthquakes were detected by the seismic network daily or nearly daily. Weather clouds sometimes obscured satellite and webcam views; elevated surface temperatures were identified in satellite data during 21-22 September. Towards the end of the week radar satellite images showed advancement of the SW part of the lava flow and associated rockfalls at the flowâ??s margins. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale). Geologic Summary. The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an older edifice and produced a submarine debris avalanche. Deposits from this and an even older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Eruptions have been recorded since the late-19th century. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFr8O3UB6A$> Ibu | Indonesia | 1.4941°N, 127.6324°E | Summit elev. 1357 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 17-23 September. Dense gray or white-and-gray ash plumes rose 400-700 m above the summit and drifted W, NW, and NE. Incandescence at the summit was visible in several nighttime webcam images. The Alert Level remained at 2 (the second lowest level on a four-level scale) and the public was advised to stay 2 km away from the active crater and 3.5 km away from the N crater wall opening. Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Karymsky | Russia | 54.049°N, 159.443°E | Summit elev. 1513 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate activity continued at Karymsky during 11-18 September. A thermal anomaly was identified in satellite images on 12 September; weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ <https://urldefense.com/v3/__http://kvert.febras.net/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFppxgoC1Q$> Katmai | United States | 58.279°N, 154.9533°W | Summit elev. 2047 m The Alaska Volcano Observatory (AVO) reported that on 22 September strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes dispersed unconsolidated ash up to 1.8 km (6,000 ft) a.s.l. to the SE. The ash was originally deposited during the Novarupta-Katmai eruption in 1912. The Volcano Alert Level remained at Normal (the lowest level on a four-level scale) and the Aviation Color Code remained at Green (the lowest level on a four-color scale). Geologic Summary. Katmai was initially considered to be the source of the Valley of Ten Thousand Smokes ash flow in 1912. However, the 3 x 4 km caldera of 1912 is now known to have formed as a result of the voluminous eruption at nearby Novarupta volcano. The edifice had four NE-SW-trending summits, most of which were truncated by the 1912 collapse. Two or more large explosive eruptions took place during the late Pleistocene. Most of the two overlapping pre-1912 Katmai volcanoes are Pleistocene, but Holocene lava flows from a flank vent descend the SE flank of the SW edifice into the Katmai River canyon. The steep walled young caldera has a jagged rim that rises 500-1,000 m above the caldera floor and contains a deep lake. Lake waters have covered a small post-collapse lava dome (Horseshoe Island) that was seen on the caldera floor at the time of the initial ascent to the caldera rim in 1916. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFr8O3UB6A$> Kilauea | United States | 19.421°N, 155.287°W | Summit elev. 1222 m The Hawaiian Volcano Observatory (HVO) reported that the eruption within Kilaueaâ??s Kaluapele summit caldera, characterized by episodic fountaining, incandescence, and intermittent spatter from craters along the SW margin of Halemaâ??umaâ??u Crater, continued at variable levels during 16-23 September. Incandescence at both the N and S vents was visible overnight during 16-17 September. Gas pistoning (a shallow, gas-driven rise and fall of a lava surface) at the N vent was followed by brief overflows of lava beginning at 0838 on 17 September. Overflows became larger during 17-18 September and dome fountains that were 3-6 m high accompanied the filling and overflowing of the vent. Drainbacks of lava were marked by energetic bursts of gas that sent spatter 5-10 m high and landed on the outside of the cone. Continuous low lava fountains began at approximately 0244 on 19 September and intensified until 0311, when fountains rose up to 150 m and large lava flows began advancing onto the crater floor. An eruption plume rose 3 km above the ground surface and drifted SW. Fountains initially rose as high as 240 m but by 0921 they were just over 100 m high and inclined about 60 degrees towards the E. The S vent began erupting at unspecified time then stopped at around 0600. After nine hours of continuous fountaining at the N vent, the eruption abruptly ended at 1208. Approximately 6.3 million cubic meters of lava had erupted, and lava flows covered about two thirds of the Halemaâ??umaâ??u Crater floor. Minor incandescence was recorded daily at the S vent, and during most days at the N vent, during 20-23 September. Gas plumes continued to be emitted from the vents. 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://volcanoes.usgs.gov/observatories/hvo/ <https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFoOtVVKSw$> Klyuchevskoy | Russia | 56.056°N, 160.642°E | Summit elev. 4754 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that ash deposited on the N flank of Klyuchevskoy during previous eruptions was resuspended by strong winds and drifted more than 575 km SE on 23 September. The Aviation Color Code was raised to Yellow (the second lowest level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified. Geologic Summary. Klyuchevskoy is the highest and most active volcano on the Kamchatka Peninsula. Since its origin about 6,000 years ago, this symmetrical, basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during approximately the past 3,000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 and 3,600 m elevation. Eruptions recorded since the late 17th century have resulted in frequent changes to the morphology of the 700-m-wide summit crater. These eruptions over the past 400 years have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ <https://urldefense.com/v3/__http://kvert.febras.net/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFppxgoC1Q$> Krasheninnikov | Russia | 54.596°N, 160.27°E | Summit elev. 1816 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that the eruption at Krasheninnikov continued during 11-18 September. A daily large thermal anomaly over the volcano was identified in satellite images. A thermal anomaly in Northern Cone and over two active lava flows on the E flank were visible in Sentinel satellite images during 13 and 17-18 September. Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified. Geologic Summary. The late-Pleistocene to Holocene Krasheninnikov volcano is comprised of two overlapping stratovolcanoes within a 9 x 10 km Pleistocene caldera. Young lava flows from summit and flank vents descend both into the caldera and down its outer flanks, and older flows that covered much of the SE caldera rim extended downslope at least 7 km. Tephra deposits from the caldera-forming eruption directly overlie a 39,000 years before present (BP) tephra thought to be associated with the formation of Uzon caldera (Florenskii, 1988). The intra-caldera stratovolcanoes are situated along a NE-SW-trending fissure that has also produced zones of Holocene cinder cones extending 15-20 km beyond the caldera. Construction of the southern edifice began about 11,000 years BP and lasted for about 4,500 years; it has a summit crater about 800-900 m wide. The northern edifice was constructed during a cycle of similar length that began about 6,500 years ago; it has a summit crater about 1.5 km wide, within which is low cone with an 800-m-wide crater containing another small cone. An eruptive cycle during about 600-400 years BP (1350-1550 CE) produced the Pauk lava cone in the crater of the northern cone and the Yuzhny lava flow on SW flank outside the caldera, followed by the Molodoy flow from the upper SW flank (Ponomareva, 1987; Ponomareva and Tsyurupa, 1985; Ponomareva and Braitseva, 1990). Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ <https://urldefense.com/v3/__http://kvert.febras.net/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFppxgoC1Q$> ; Copernicus https://www.copernicus.eu/en <https://urldefense.com/v3/__https://www.copernicus.eu/en__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFp9Xn_0_Q$> Kuchinoerabujima | Japan | 30.443°N, 130.217°E | Summit elev. 657 m The Japan Meteorological Agency (JMA) reported that the number of shallow volcanic earthquakes at Kuchinoerabujima began to decline in July and remained low. Visits to the volcano on 7 and 9 September confirmed no notable changes to hydrothermal fields in and around Furudake Crater and Shindake Crater (just N of Furudake) and no emissions were visible. The Alert Level was lowered to 1 (on a scale of 1-5) at 1100 on 19 September. Geologic Summary. A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km W of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. All historical eruptions have occurred from Shindake, although a lava flow from the S flank of Furudake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shindake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrh4VZhXQ$> Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that on 19 September the seismic network at Lewotobi Laki-laki recorded an increase in the number of low-frequency earthquakes, followed by an eruption at 1432 that produced ash plumes that rose 500-1,000 m above the summit. The Alert Level was raised to 4 (the highest level on a scale of 1-4) at 2100 and the exclusion zone was increased to 6 km from the center of Laki-laki and 7 km in a semicircle clockwise from the SW to the NE. At 2158 eruptive activity became continuous and remained continuous at least through 2229, with ash plumes rising 800-1,500 m above the summit and drifting SW. At 2246 an ash plume rose around 6 km above the summit and drifted W and SW and a webcam at that same time showed incandescent material on the upper flanks. Incandescent material being ejected straight up above the summit and falling onto the upper flanks was visible in a 2254 webcam image. Ash plumes rose 3 km above the summit and drifted W and SW at 2307, at 2327, and at 2341. Ash-and-gas emissions were continuous for most of 20 September. Multiple eruptive events produced ash plumes that rose as high as 3 km above the summit and drifted NW, W, and SW. Summit incandescence was visible in a few of the webcam images. According to a news report three flights using the Komodo International Airport, around 300 km W, were canceled on 20 September and two were rescheduled for the next day. Multiple eruptive events were recorded on 21 September. Ash plumes again rose as high as 3 km above the summit and drifted N, NW, W, and SW. Ash plumes during 22-23 September rose 600-2,000 m above the summit and drifted NW, W, and SW. Minor incandescence at the summit was visible in a webcam image at 1915 on 22 September. Geologic Summary. The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the "husband and wife"). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan. Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> ; Antara News https://www.antaranews.com/berita/5123341/enam-penerbangan-di-bandara-komodo-batal-dampak-erupsi-gunung-lewotobi <https://urldefense.com/v3/__https://www.antaranews.com/berita/5123341/enam-penerbangan-di-bandara-komodo-batal-dampak-erupsi-gunung-lewotobi__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFpoWAZLlQ$> Lewotolok | Indonesia | 8.274°S, 123.508°E | Summit elev. 1431 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 17-23 September. On most days white-and-gray ash plumes rose 300-600 m above the summit of the cone and drifted W and NW; only white plumes were observed on 21 and 23 September. Several nighttime webcam images showed Strombolian ejections of incandescent material above the cone and onto the flanks. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit. Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Marapi | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 17-23 September. Almost daily white steam-and-gas plumes rose as high as 200 m above the crater rim and drifted in multiple directions. Eruptive events were recorded on 17, 22, and 23 September, but weather conditions prevented visual confirmation. Dense gray ash plumes rose 1 km above the summit and drifted S and SW during 20-21 September. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active crater. Geologic Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Merapi | Indonesia | 7.54°S, 110.446°E | Summit elev. 2910 m The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 12-18 September. Earthquakes were less intense compared to the previous week. The SW lava dome produced 11 lava avalanches that traveled as far as 2 km SW down the Bebeng drainage, 36 that traveled as far as 2 km SW down the Krasak drainage, and 62 that traveled as far as 2 km W down the Sat/Putih drainage. One pyroclastic flow traveled 2 km down the Krasak drainage. Small morphological changes to the SW lava dome resulted from lava effusion and minor collapses. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit, based on location. Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) http://www.merapi.bgl.esdm.go.id/ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFpSjqUbFw$> Nyamulagira | DR Congo | 1.408°S, 29.2°E | Summit elev. 3058 m The eruption at Nyamulagira continued during 3-18 September. Incandescence on the floor of the summit caldera and from active lava flows on the W and NW flanks was visible in satellite images on 3, 8, 13, and 18 September. Weather clouds obscured parts of the summit area and the flanks in all four images. Geologic Summary. Africa's most active volcano, Nyamulagira (also known as Nyamuragira), is a massive high-potassium basaltic shield about 25 km N of Lake Kivu and 13 km NNW of the steep-sided Nyiragongo volcano. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Documented eruptions have occurred within the summit caldera, as well as from the numerous flank fissures and cinder cones. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Recent lava flows extend down the flanks more than 30 km from the summit as far as Lake Kivu; extensive lava flows from this volcano have covered 1,500 km2 of the western branch of the East African Rift. Source: Copernicus https://www.copernicus.eu/en <https://urldefense.com/v3/__https://www.copernicus.eu/en__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFp9Xn_0_Q$> Popocatepetl | Mexico | 19.023°N, 98.622°W | Summit elev. 5393 m The Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 16-23 September. The seismic network recorded 32-80 long-period events per day, accompanied by steam-and-gas emissions with occasional minor ash content. In addition, the seismic network recorded daily periods of low-amplitude tremor, characterized by harmonic tremor and high-frequency signals, lasting from two hours and 52 minutes to 7 hours and 42 minutes. A minor explosion was recorded at 0148 on 22 September. A webcam image from 0149 showed a small amount of incandescent material on the upper flanks. An explosion at 0049 on 23 September also ejected incandescent material a short distance onto the upper flank. According to the Washington VAAC ash plumes visible in webcam and/or satellite images during 16-18 and 20-22 September rose 5.8-6.7 km (20,000-22,000 ft) a.s.l. (about 400-1,300 m above the crater rim) and drifted as far as 46 km W, WSW, and SW. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater. Geologic Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time. Sources: Centro Nacional de Prevencion de Desastres (CENAPRED) https://www.gob.mx/cenapred <https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFqaOKFW2w$> ; Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html <https://urldefense.com/v3/__http://www.ssd.noaa.gov/VAAC/messages.html__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFqGWVmaQQ$> Santa Maria | Guatemala | 14.757°N, 91.552°W | Summit elev. 3745 m The Instituto Nacional de SismologÃa, VulcanologÃa, MeteorologÃa e HidrologÃa (INSIVUMEH) reported high levels of ongoing eruptive activity at Santa Mariaâ??s Santiaguito dome complex during 16-23 September, with continuing lava extrusion at Caliente dome. Daily explosions, 2-6 per hour when reported, generated gas-and-ash plumes that rose 700-1,000 m above the dome and drifted in multiple directions. Effusion of blocky lava and collapses of previous deposits produced block avalanches that descended mainly the W and SW flanks; the collapsed material produced short pyroclastic density currents during 22-23 September. Incandescence during dark hours was visible from Caliente dome and block avalanches. Special reports issued at 1305 on 16 September and at 1337 on 20 September noted that heavy rainfall generated hot lahars in the Cabello de Ã?ngel drainage (SE). The lahars were a mixture of water and sediments, along with tree trunks, branches, and blocks up to 3 m in diameter, and a sulfur odor. Hot lahars moving down the Tambor drainage (SSW) were noted in special reports issued at 1317 on 16 September, at 1345 on 18 September, and at 1346 on 20 September. These lahars were also a mixture of water and sediments, with tree trunks, branches, and blocks up to 1 m in diameter, and a sulfur odor. Geologic Summary. Symmetrical, forest-covered Santa MarÃa volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing E towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFqLFOHpYQ$> Semeru | Indonesia | 8.108°S, 112.922°E | Summit elev. 3657 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 17-23 September, with daily eruptive events recorded by the seismic network. White-and-gray ash plumes rose 300-700 m above the summit and drifted in multiple directions during 22-23 September. Emissions were not visible on the other days. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 3 km away from the summit in all directions, 8 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 13 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards. Geologic Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrJu_Bl8g$> Sheveluch | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing eruptive activity at Sheveluchâ??s â??300 years of RASâ?? dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 11-18 September. Ash plumes were identified in satellite images drifting 215 km W and E during 12 and 17-18 September and thermal anomalies over the domes were identified during 13 and 17-18 September; weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ <https://urldefense.com/v3/__http://kvert.febras.net/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFppxgoC1Q$> Stromboli | Italy | 38.789°N, 15.213°E | Summit elev. 924 m The Sezione di Catania - Osservatorio Etneo (INGV) reported that eruptive activity continued at Stromboli during 15-21 September. Webcam images showed Strombolian activity at four vents in Area N within the upper part of the Sciara del Fuoco, and from at least two vents in Area C-S (South-Central Crater) on the crater terrace. The vents in Area N continued to produce low- to medium-intensity explosions at a rate of 2-8 events per hour, ejecting lapilli and bombs less than 150 m above the vents. Low- to medium-intensity explosions ejected tephra from the vents in Area C-S at a rate of 2-5 times per hour. Some explosions ejected the tephra as far as the margins of the crater terrace. The Alert Level remained at Yellow (the second lowest level on a four-level scale) according to the Dipartimento della Protezione Civile. Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli have long attracted visitors to the "Lighthouse of the Mediterranean" in the NE Aeolian Islands. This volcano has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small island is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period took place between about 13,000 and 5,000 years ago. The active summit vents are located at the head of the Sciara del Fuoco, a prominent scarp that formed about 5,000 years ago due to a series of slope failures which extends to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded for more than a millennium. Sources: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrkUBSaUg$> ; Dipartimento della Protezione Civile https://www.protezionecivile.gov.it/it/ <https://urldefense.com/v3/__https://www.protezionecivile.gov.it/it/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFptE_7_AA$> Suwanosejima | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 8-15 September. Incandescence was observed nightly in webcam images. Eruptive events during 15-17, 19, and 21 September generated ash plumes that rose 1-1.8 km above the crater rim and drifted N, E, and SE. Large blocks were occasionally ejected as high as 300 m above the vent. The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to be cautious within 1.5 km of the crater. Geologic Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!alX6wICj3dzIH6MYqyPpW7tRz1sS2izyTp7SacsnUReF5ATCwSqvHwjWT9JSik7_-JnPU-h80ydkgRFRpFrh4VZhXQ$> 3-3-3-3-3-3-3-3-3-3-3-3-3 ============================================================== Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI). ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - http://www.volcano.si.edu/ IAVCEI - https://www.iavceivolcano.org/ To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx. To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments. ============================================================== ------------------------------ End of Volcano Digest - 23 Sep 2025 to 24 Sep 2025 (#2025-90) *************************************************************
