5-5-5-5-5-5-5-5-5-5-5-5-5-5 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 9-15 July 2025 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm New Activity/Unrest: Apaneca Range, El Salvador | Erta Ale, Ethiopia | Kirishimayama, Japan | Lewotobi, Indonesia | Lewotolok, Indonesia | Reykjanes, Iceland | Telica, Nicaragua Ongoing Activity: Aira, Japan | Bezymianny, Russia | Dukono, Indonesia | Fuego, Guatemala | Great Sitkin, United States | Ibu, Indonesia | Kilauea, United States | Marapi, Indonesia | Merapi, Indonesia | Papandayan, Indonesia | Poas, Costa Rica | Popocatepetl, Mexico | Rainier, United States | Raung, Indonesia | Santa Maria, Guatemala | Semeru, Indonesia | Sheveluch, Russia | 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 Apaneca Range | El Salvador | 13.872°N, 89.742°W | Summit elev. 2028 m According to the Universidad de El Salvador a hydrothermal explosion occurred at Agua Shuca, a fumarolic field and lake (roughly 30 x 60 m) in the SW part of the Ahuachapán Geothermal Field in the Apaneca Range, on 10 July. Video of the event showed steam-and-gas plumes expanding from the lake area, ejections of boiling sediment and water, and waves of muddy water flowing over the surrounding land; a few people were seen running from the area, with one person taking shelter behind a wall. A team from the Universidad de El Salvador traveled to the area the next day to assess the event and the impacts, to take measurements, and to provide information to the nearby residents. The explosion created a crater about 70 m in diameter and 20 m deep. Photos indicated that mud and water were ejected mainly to the SE, covering an extending beyond a road, but deposits were seen around the margins of the lake in most directions. Gas emissions were low, suggesting that activity had returned to baseline levels; Agua Shuca does not have a monitoring network. Geologic Summary. The Apaneca Range (also known as the Cuyanausul Range) consists of a group of basaltic-to-andesitic Pleistocene and Holocene stratovolcanoes in western El Salvador between the Santa Ana complex and the Guatemala border. The Pleistocene dacitic-rhyolitic Concepción de Ataco caldera (5 x 3.5 km) lies at the W end of the complex, along with post-caldera late-Pleistocene to Holocene andesitic-dacitic lava domes. The post-caldera cones of Cerro el Aguila (the highest peak of the complex) and Cerro los Naranjos at the E end of the chain were mapped as Holocene by Weber and Weisemann (1978). Young craters on the basaltic Cerro Laguna Verde stratovolcano may also have been active during the Holocene. Numerous fumarole fields are located on the N flank of the range, and the Ahuachapán geothermal field has been producing since 1975. Several small hydrothermal explosions have occurred in historical time, including one in October 1990 at the Agua Shuca thermal area in which 26 people were killed. Sources: Universidad de El Salvador https://www.ues.edu.sv/; El Universitario (Universidad de El Salvador) https://eluniversitario.ues.edu.sv/ues-realiza-monitoreo-cientifico-tras-explosion-hidrotermal-en-ahuachapan/?fbclid=IwY2xjawLjfoBleHRuA2FlbQIxMABicmlkETF6YjBSZ1NCOGl5MnZoakZIAR6I3qiSGuyyaW38uT_-TMFzfRNP-3Vh3cZqwdCjIXcDbxwcnZIhxnfo_DMPqg_aem_bwTyJ70bzp3Ibutm4z8y8g ; hoycomsv https://www.hoy.com.sv/salud-y-bienestar/explosion-hidrotermal-en-agua-shuca-no-representa-riesgo-volcanico-confirman-autoridades/ ; Canal 12 https://www.youtube.com/watch?v=J7XPvxhGbnM Erta Ale | Ethiopia | 13.601°N, 40.666°E | Summit elev. 585 m Eruptive activity at Erta Ale continued during July based on satellite data and field observations. Small thermal anomalies at both the N and S pit craters were visible in periodic satellite image views on 1, 6, 8, and 11 July. On 15 July a dense black plume rising from an unstated area was filmed by a local observer and was thought to have originated from a collapse of a portion of crust covering a lava lake. A post on social media showed pictures of the plumes and stated that the plumes sank to the ground and spread out over an area of 15 km. Plumes were visible on 16 July. Geologic Summary. The Erta Ale basaltic shield volcano in Ethiopia has a 50-km-wide edifice that rises more than 600 m from below sea level in the Danakil depression. The volcano includes a 0.7 x 1.6 km summit crater hosting steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located SE of the summit and is bounded by curvilinear fault scarps on the SE side. Basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera usually also holds at least one long-term lava lake that has been active since at least 1967, and possibly since 1906. Recent fissure eruptions have occurred on the N flank. Sources: Copernicus https://www.copernicus.eu/en; Sputnik https://x.com/sputnik_afrique/status/1945486118893547783; Adal state https://x.com/SonKalifa Kirishimayama | Japan | 31.934°N, 130.862°E | Summit elev. 1700 m The Japan Meteorological Agency (JMA) reported that eruptive activity continued at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group) during 10-16 July. The number of volcanic earthquakes with epicenters directly beneath Shinmoedake had been fluctuating since late October 2024; volcanic tremor was occasionally detected. Eruptive activity occurred intermittently with grayish-white plumes rising as high as 400 m above the crater rim. On 15 July sulfur dioxide emissions were high, averaging 1,600 tons per day. The Alert Level remained at 3 (on a 5-level scale) and the public was warned to exercise caution within 3 km from Shinmoedake Crater. Geologic Summary. Kirishimayama is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene dominantly andesitic group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located Karakunidake being the highest. Onamiike and Miike, the two largest maars, are located SW of Karakunidake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Miike to Ohachi, and at Shinmoedake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Lewotobi Laki-laki during 8-15 July. Avalanches of material were occasionally detected during the week but not observed. Dense gray ash plumes rose 1.2-4 km above the summit and drifted W and NW. Summit incandescence was visible on 10 July. At 1410 on 11 July a dense gray ash plume rose 4 km above the summit and drifted W and NW. Eruptive events were detected on 9 and 14 July, but weather clouds prevented visual observations. The Alert Level remained at 4 (on a scale of 1-4) and on 25 June the exclusion zone was reduced to 6 km from the center of Laki-laki and 7 km in a semicircle clockwise from the SW to the NE. 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/; Antara News https://www.antaranews.com/berita/4958593/badan-geologi-aktivitas-gunung-lewotobi-masih-tinggi-statusnya-awas ; Antara News https://www.antaranews.com/berita/4958593/badan-geologi-aktivitas-gunung-lewotobi-masih-tinggi-statusnya-awas 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 2-15 July. White plumes on 9 and 12 July rose 100 m above the summit and drifted W and NW. Gray or white-to-gray ash plumes rose 200-400 m above the summit of the cone and drifted W during 10-11 and 13-15 July. Clear nighttime webcam images showed incandescent material being ejected above the cone. 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/ Reykjanes | Iceland | 63.817°N, 22.717°W | Summit elev. 140 m The Icelandic Meteorological Office (IMO) reported that an eruption began on 16 July in an area NE of Stóra Skógfell, along the Sundhnúkur crater row, within the Reykjanes volcanic system. IMO issued a Volcano Observatory Notices for Aviation (VONA) at 0106, raising the Aviation Color Code to Red (the highest level on a four-color scale), after monitoring data indicated a dike intrusion. An intense seismic swarm that began at 0120 was located between Stóra-Skógfell and Sýlingarfell, and deformation data indicated that the dike was propagating towards the S and rising to the surface. A fissure eruption began at 0356. The eruption was observed in webcams along with both drone and helicopter overflights. Lava fountains rose along the fissure, but no ash was present in the air; the Aviation Color Code was lowered to Orange at 0435. By 0505 the fissure was 700-1,000 m long and opening towards the N. Lava fountains continued to rise along the fissure and lava flows traveled mostly SE. Seismicity had decreased by 0845. Lava flows advanced W and to a greater extent to the E. Peleâ??s hair drifted downwind. High levels of volcanic gases were measured in Reykjanesbær prompting authorities to advise residents to stay indoors. By noon two fissures were erupting; the larger fissure at the Sundhnúkur crater row was about 2.4 km long, and a smaller fissure, about 500 m long, had opened W of Fagradalsfjall. Geologic Summary. The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial basaltic crater rows and small shield volcanoes. The submarine Reykjaneshryggur volcanic system is contiguous with and is considered part of the Reykjanes volcanic system, which is the westernmost of a series of four closely-spaced en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of the subaerial part of the system (also known as the Reykjanes/Svartsengi volcanic system) is covered by Holocene lavas. Subaerial eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system, and numerous submarine eruptions dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Basaltic rocks of probable Holocene age have been recovered during dredging operations, and tephra deposits from earlier Holocene eruptions are preserved on the nearby Reykjanes Peninsula. Source: Icelandic Meteorological Office (IMO) http://en.vedur.is/ Telica | Nicaragua | 12.606°N, 86.84°W | Summit elev. 1036 m The Washington Volcanic Ash Advisory Center (VAAC) reported that at 0600 on 14 July a diffuse ash plume from Telica was identified in a satellite image drifting about 20 km S at an altitude of 1.5 (5,000 ft) a.s.l. The ash emission was also visible in webcam views. Geologic Summary. Telica, one of Nicaragua's most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately E, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby. Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html 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 7-14 July. Nightly crater incandescence was visible in webcam images. Explosions at 0440 and 2314 on 9 July and at 1629 on 10 July, produced ash plumes that rose as high as 1.8 km above the crater rim and drifted W and NW. The first and last explosions ejected large blocks as far as 900 m from the vent. Ash plumes from eruptive activity on 13 July rose 1.1 km above the crater rim and drifted NW. 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/ Bezymianny | Russia | 55.972°N, 160.595°E | Summit elev. 2882 m The Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) reported that eruptive activity at Bezymianny continued during 6-13 July. Gas-and-ash plumes rose as high as 5 km a.s.l., or around 2.1 km above the summit, and drifted W and SW during 6-7 July. Gas-and-steam plumes with possible ash content rose as high as 3.3 km a.s.l., or about 400 m above the summit, and drifted SW and W during 8-9 July. Thermal anomalies were visible during 6-10 July. Weather clouds obscured views during 10-13 July. 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. Source: Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) http://www.kscnet.ru/ivs/ 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 9-15 July. Daily white-and-gray or gray-to-black gas-and-ash plumes rose 400-1,200 m above the summit and drifted NE and E. Faint booming and rumbling was heard and felt by residents 10-11 km away. 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/ 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 8-15 July. Incandescence at the summit was occasionally observed in webcam images. During 8-9 July a gas-and-steam plume with minor ash content rose from the summit crater. Block avalanches descended the Ceniza (SSW) drainage, producing plumes of ash that rose along the pathways. A small ash emission drifted S and SW during 9-10 July. Two weak explosions during 12-13 July produced ash-and-gas plumes that rose as high as 650 m above the summit and drifted 4-6 km W. Fumarolic plumes were visible on the other days. Lahars descended the Ceniza, Zarco, and Mazate drainages on 14 July, carrying tree branches, trunks, volcanic material, and blocks 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/ 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 9-15 July. Lava-flow advancement was concentrated at the SW lobe. Small daily earthquakes were detected by the seismic network, including signals probably caused by small rockfalls from the steep flanks. Elevated surface temperatures consistent with lava effusion were observed in clear satellite views during the week. 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/ Ibu | Indonesia | 1.488°N, 127.63°E | Summit elev. 1325 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 9-15 July. Almost daily dense gray or white-to-gray ash plumes rose 200-600 m above the summit and drifted NE and SE; weather conditions obscured views on 9 July. Nighttime crater incandescence was visible in some webcam images. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5 km away from the N crater wall opening. Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ 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 and intermittent spatter at two vents along the SW margin of Halemaâ??umaâ??u Crater, continued at variable levels during 9-15 July. Cycles of minor lava spattering, lava jetting, and gas flames were visible during 7-8 July. Activity increased at 0410 on 9 July with a large lava overflow and fountaining at the N vent. At 0515 the lava fountains became higher and more vigorous, rising to 365 m. Eruption plumes consisting of gas, ash, and Peleâ??s Hair, rose above the ground and drifted SW. According to the Washington VAAC ash plumes visible in satellite images at 0626 and 0706, and in webcam images, drifted about 55 km W at 3 km (10,000 ft) a.s.l., and then at 1236 a gas-and-steam plume with minor amounts of ash drifted about 37 km SW. Lava flows covered a portion of the crater floor, advancing about halfway across the floor by 1100 based on a helicopter overflight. The fountain occasionally fanned out from the vent and was sometimes bifurcated near the top. After nine hours of continuous fountaining, of which eight were high fountaining, the N vent stopped erupting at 1320. The growing cone around the N vent began to connect with the top of the surrounding caldera wall in some places. No activity at the S vent was observed and it was completely covered by new deposits. After the fountaining episode had ended geologists inspected the tephra deposit SW of the eruptive vents, in the closed area of Hawaiâ??i Volcanoes National Park. They noted that the tephra continued to accumulate, building a mound more than 25 m high and covering parts of Crater Rim Drive. During 10-15 July slumping of the eruptive cone around the vent area was apparent in webcams as it exposed significant incandescent material. 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. 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. Sources: US Geological Survey Hawaiian Volcano Observatory (HVO) https://volcanoes.usgs.gov/observatories/hvo/; Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html 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 9-15 July. Eruptive events were recorded at 0022 and 0045 on 11 July and at 0318 and 1915 on 14 July, though not visually observed. The Darwin VAAC stated that an ash plume was visible in a satellite image at 0054 on 11 July rising to 4.3 km (14,000 ft) a.s.l. (about 1.4 km above the summit) and drifting NE. 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. Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/; Darwin Volcanic Ash Advisory Centre (VAAC) http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml 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 4-10 July. Earthquake activity was more intense than the previous week. The SW lava dome produced 19 lava avalanches that traveled as far as 2 km SW down the Bebeng drainage, 22 that traveled as far as 1.8 km SW down the Krasak drainage, and 76 that traveled as far as 2 km W down the Sat/Putih drainage. One pyroclastic flow descended the Krasak drainage as far as 2.5 km and afterward minor ashfall was reported in Tunggularum (8 km SW) of Sleman Regency and Ngori (11 kmSW) of Magelang Regency. Small morphological changes to the SW lava dome resulted from continuing 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/ Papandayan | Indonesia | 7.32°S, 107.73°E | Summit elev. 2665 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that blue flames on the crater walls of Papandayanâ??s Baru Crater were visible at 1900 on 12 July. The blue flames suggested increased temperatures at the solfatara along with the presence of oxidized sulfur. Dense emissions were seen rising 15-30 m from the crater at 2140 during a field visit. The plumes drifted W. The report noted that white plumes rose 5-30 m from both Baru and Mas craters during 1-12 July. Blue flames were last observed in March 2023. The Alert Level remained at 1 (on a scale of 1-4) and tourists were advised to stay 500 m away from the active craters. Geologic Summary. Papandayan is a complex stratovolcano with four large summit craters, the youngest of which was breached to the NE by collapse during a brief eruption in 1772 and contains active fumarole fields. The broad 1.1-km-wide, flat-floored Alun-Alun crater truncates the summit of Papandayan, and Gunung Puntang to the north gives a twin-peaked appearance. Several episodes of collapse have created an irregular profile and produced debris avalanches that have impacted lowland areas. A sulfur-encrusted fumarole field occupies historically active Kawah Mas ("Golden Crater"). After its first historical eruption in 1772, in which collapse of the NE flank produced a catastrophic debris avalanche that destroyed 40 villages and killed nearly 3000 people, only small phreatic eruptions had occurred prior to an explosive eruption that began in November 2002. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ Poas | Costa Rica | 10.2°N, 84.233°W | Summit elev. 2697 m The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported continuing gas-and-steam emissions at Poás during 8-15 July. Strong incandescence at Boca A vent was observed and the level of the hyperacid lake over Boca C remained stable. Sulfur dioxide emissions remained high and were between 500 and 1,500 tons per day during the week. The Alert Level remained at 2 (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest color on a four-color scale). Geologic Summary. The broad vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the complex stratovolcano extends to the lower N flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since an eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ 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 7-15 July. Between six and 87 low-energy, long-period (LP) seismic events occurred daily, accompanied by primarily gas and steam emissions. The emissions contained minor amounts of ash during 13-15 July. Daily low-amplitude tremor, consisting of high-frequency and harmonic signals, lasted between about six and a half hours to around 18 and a half hours. The Washington Volcanic Ash Advisory Center (VAAC) stated that an ash plume rose to 6.7 km (22,000 ft) a.s.l. (around 1.3 km above the summit) and drifted NNE. On 12 July a gas-and-steam plume with possible ash rose to 6 km (20,000 ft) a.s.l. and drifted NW. A diffuse ash plume drifted NW on 13 July. 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; Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html Rainier | United States | 46.853°N, 121.76°W | Summit elev. 4392 m The Cascades Volcano Observatory (CVO) reported that a seismic swarm at Rainier that began at 0129 on 8 July continued through 15 July, though at a slower rate. As of 1100 on 15 July CVO and the Pacific Northwest Seismic Network (PNSN) had located 540 events since the start of the swarm; many more could not be located. The rate of earthquakes decreased from 33 located events per hour at the swarm's peak during the morning of 8 July to a couple events per hour by 9 July; the rate remained at the lower rate during the rest of the week. The largest event of the swarm was a M 2.4 that occurred at 1223 on 11 July. 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 color on a four-color scale). Geologic Summary. Mount Rainier is a heavily glaciated andesitic volcano in the Puget Sound region. Large Holocene mudflows from collapse have reached as far as the Puget Sound lowlands. The present summit was constructed within a large crater breached to the NE, formed by collapse during a major explosive eruption about 5,600 years ago that deposited the widespread Osceola Mudflow. Rainier has produced eruptions throughout the Holocene, including about a dozen during the past 2,600 years; the largest of these occurred about 2,200 years ago. The present summit cone is capped by two overlapping craters. Extensive hydrothermal alteration of the upper portion of the volcano has contributed to its structural weakness; an active thermal system has caused periodic melting on flank glaciers and produced an elaborate system of steam caves in the summit icecap. Reported uncertain 19th-century eruptions, including a possible but not confirmed phreatic eruption in 1894, have not left identifiable deposits. Source: US Geological Survey Cascades Volcano Observatory (CVO) https://volcanoes.usgs.gov/observatories/cvo/ Raung | Indonesia | 8.119°S, 114.056°E | Summit elev. 3260 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Raung continued during 9-15 July. On most days white plumes were visible rising as high as 800 m above the summit and drifting N and S; weather conditions sometimes prevented visual observations. At 1923 on 11 July an ash plume was seen by a ground observer rising 800 m above the summit and drifting S and SW. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit 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) http://vsi.esdm.go.id/ 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 8-15 July with continuing lava extrusion at Caliente dome. Daily explosions, 1-2 per hour when reported, generated gas-and-ash plumes that rose as high as 1 km above the dome and drifted as far as 30 km W and SW. Effusion of blocky lava and collapses of material produced block avalanches that descended multiple flanks; the collapsed material sometimes produced short pyroclastic flows that reached the base of the volcano. Incandescence was visible at Caliente dome and upper part of the W flank lava flow. Minor ashfall was reported in communities surrounding the volcano during 8-9 July inclsuing San Marcos (10 km SW), Loma Linda (7 km W), Palajunoj (17 km SSW). 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/ 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 2-8 July, often with multiple daily eruptive events recorded by the seismic network. Dense white-and-gray or gray ash plumes rose 400-1,000 m above the summit and drifted W, SW, and S during 9, 11, and 13-14 July. Incandescence at the summit was visible in a 14 July webcam image. Events were detected on 10, 12, and 15 July, though weather conditions prevented visual observations. 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/ Sheveluch | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) reported that eruptive activity at Sheveluch continued during 6-13 July. Daily gas-and-ash plumes from the lava-dome complex rose as high as 4 km a.s.l., or around 750 m above the summit, and drifted W and NW during 6-8 July, based on webcam views and statements issued by the Tokyo Volcanic Ash Advisory Center (VAAC). On 9 July a gas-and-steam plume with possible ash content rose 3 km a.s.l. and drifted NW. Thermal anomalies were sometimes visible during 6-9 July. Weather clouds obscured views during 10-13 July. 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. Sources: Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) http://www.kscnet.ru/ivs/; Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html 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 7-14 July. Incandescence was observed nightly in webcam images. Eruptive events during 7-8 July produced ash plumes that usually rose 1.1-1.8 km above the crater rim and drifted NW, E, and SE, but an explosion at 1015 on 8 July sent a plume to 2 km. Minor ashfall was reported in Toshima Village (3.5 km SSW). An explosion at 0144 on 12 July generated an ash plume that rose 1.2 km above the crater rim and drifted E. 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/ 5-5-5-5-5-5-5-5-5-5-5-5-5-5 ============================================================== 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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