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 16-22 July 2025 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm New Activity/Unrest: Kirishimayama, Japan | Planchon-Peteroa, Chile | Reykjanes, Iceland | Taal, Philippines | Telica, Nicaragua Ongoing Activity: Aira, Japan | Dukono, Indonesia | Etna, Italy | Fuego, Guatemala | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Karymsky, Russia | Kilauea, United States | Klyuchevskoy, Russia | Lewotolok, Indonesia | Marapi, Indonesia | Merapi, Indonesia | Miyakejima, Japan | Nevado del Ruiz, Colombia | Reventador, Ecuador | Sangay, Ecuador | 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 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 16-21 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 1.5 km above the crater rim and drifting NW, N, and NE. Weather clouds sometimes obscured visual observations. 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/ Planchon-Peteroa | Chile | 35.223°S, 70.568°W | Summit elev. 3977 m The Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) reported that seismicity increased at Planchón-Peteroa during 13-15 July according to the Observatorio Volcanológico de los Andes del Sur (OVDAS). Beginning in March there was an increase in low-magnitude (mostly less then M2), volcano-tectonic events. On 19 June a tremor pulse was detected that had deep-source characteristics. Earthquakes associated with internal fluid movement began to be recorded on 13 July, though the events were low energy and occurred at a low rate. Seismicity increased at 0800 on 15 July and consisted of long-period (LP) earthquakes and tremor pulses. From 13 July to 1640 on 16 July the network recorded more than 1,200 low-energy seismic events and there was a shift to more LP-type seismicity. On 18 July the Alert Level was raised to Yellow (the middle level on a three-color scale) and the public was warned to stay 2 km away from the center of the active craters. The Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED) stated that the communities of Molina (66 WNW), Curicó (68 km NW), Romeral (75 km NW), and Teno (68 km NW) were placed under â??Preventive Early Warningâ?? and that only residents were allowed within a 4 km radius of the craters. Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic andesite to dacitic Volcán Azufre, followed by formation of the basaltic and basaltic andesite Volcán Planchón, 6 km N. About 11,500 years ago much of Azufre and part of Planchón collapsed, forming the massive RÃo Teno debris avalanche, which traveled 95 km to reach Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic andesite Volcán Peteroa, consists of scattered vents between Azufre and Planchón, and and contains a small steaming crater lake. Reported eruptions from the complex have been dominantly explosive, although lava flows were emplaced in 1837 and 1937. Sources: Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) http://www.sernageomin.cl/; Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED) https://senapred.cl/ Reykjanes | Iceland | 63.817°N, 22.717°W | Summit elev. 140 m The Icelandic Meteorological Office (IMO) reported that a fissure eruption within the Reykjanes volcanic system began on 16 July in an area NE of Stóra Skógfell, along the Sundhnúkur crater row. According to a news report, the eruption was preceded by a seismic swarm and deformation, prompting authorities to evacuate 20-30 people from the GrindavÃk campground, about 100 people from the town of GrindavÃk, and about 200 people from the Blue Lagoon spa. A fissure trending NE-SW opened at around 0356 and propagated N. Lava flows spread laterally from the fissure, mainly to the SE. As the eruption progressed, a second fissure opened. For a short period of time the interaction of groundwater and magma produced tephra-laden gas-and-steam plumes. By noon the entire fissure was about 2.4 km long and consisted of a series of segments that produced lava fountains and flows, with cones forming over vents along the fissure. Lava mainly flowed N and NE, spreading widely across Kálffellsheiði and toward Svartsengi. Lava covered about 3.2 square kilometers, based on satellite images. High concentrations of sulfur dioxide were measured over the Reykjanes Peninsula and were drifting W and SW over the ocean. Smoke from vegetation fires set by the eruption contributed to poor air quality in the region. Later in the evening residents of GrindavÃk were allowed back into town. The eruption continued through the night. On 17 July seismic activity was low and eruptive activity was concentrated at about 10 vents. Lava continued to advance E. Foggy weather created poor visibility around the eruption site. Gas dispersal was widespread, with sulfur dioxide concentrations temporarily reaching hazardous levels in some localized areas, including in Akureyri. Due to high levels of volcanic gases authorities advised residents to stay indoors. By 1130 on 18 July activity was concentrated along the central part of the fissure and the seismic network recorded little to no signals. Volcanic smog (vog) had spread over most of Iceland was visible over the ocean to the N and W. By 1130 on 19 July the eruption was concentrated at 2-3 craters and volcanic tremor was low and steady. Two craters were active during 19-20 July and lava flowed E towards Fagradal. Poor air quality from significant amounts of sulfur dioxide emissions near the eruption site and vog continued to affect areas in the W half of Iceland. The northernmost crater ceased to be active at around 2200 on 21 July; one crater was active at least through 1440 on 22 July. Eastward advancement of the lava flows had slowed, and the flows inflated. IMO recommended that the public continue to check weather and gas-dispersion forecasts. 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/ Taal | Philippines | 14.0106°N, 120.9975°E | Summit elev. 311 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported eruptive activity at Taal during 16-22 July. On 15 July the seismic network recorded two volcanic earthquakes including one period of volcanic tremor lasting five minutes. Sulfur dioxide emissions averaged 504 tonnes per day. Gas-and-steam emissions rose 600 m above the crater rim and drifted ENE. No earthquakes were recorded on 16 July. Gas-and-steam emissions rose 400 m above the crater rim and drifted NE. A series of three phreatomagmatic events occurred during 1501-1513 on 17 July. Dark material was ejected above the crater rim and a voluminous eruption plume rose 2.4 km and drifted SE. Strong tremor preceded the eruption. The Alert Level remained at 1 (on a scale of 0-5); PHIVOLCS reminded the public that the entire Taal Volcano Island (TVI) was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited. Pilots were warned to avoid flying over TVI. Geologic Summary. Taal is one of the most active volcanoes in the Philippines and has produced some powerful eruptions. The 15 x 20 km Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2 surface lies only 3 m above sea level. The maximum depth of the lake is 160 m, with several submerged eruptive centers. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ Telica | Nicaragua | 12.606°N, 86.84°W | Summit elev. 1036 m The Washington Volcanic Ash Advisory Center (VAAC) reported that during 18-20 July ash plumes from Telica were identified in satellite images and/or webcam images drifting as far as 13 km SW and W at an altitude of 1.5 (5,000 ft) a.s.l. The ash emissions were periodically continuous and sometimes characterized as diffuse. 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 14-21 July. Very small eruptive events occasionally occurred during 14-16 July. Sulfur dioxide emissions were extremely high on 16 July, averaging 3,100 tons per day. An explosion at 1328 on 17 July generated an ash plume that rose 3.3 km above the crater rim and drifted N. Large blocks were ejected as far as 1 km from the vent. Ash plumes continued to rise from the crater and drift N until 1550. An eruptive event at 2000 on 18 July produced an ash plume that rose 2 km above the crater rim and drifted N. Large blocks were ejected as far as 800 m from the vent. 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/ 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 16-22 July. Daily white-and-gray gas-and-ash plumes rose 600-1,200 m above the summit and drifted NE and E. Faint booming and rumbling was heard at the observation post, 11 km N, during 16-17 July. Ashfall was reported in Tobelo City (15 km ENE) and surrounding areas (10-15 km ENE) during 18-19 July. 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/ Etna | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m The Sezione di Catania - Osservatorio Etneo (INGV) reported rising gas emissions from Etnaâ??s summit craters during 14-20 July, similar to activity observed during the previous week. After about a month of quiescence, a series of small ash emissions occurring at a rate of about once per hour began during the morning of 21 July. Geologic Summary. Mount Etna, towering above Catania on the island of Sicily, has one of the world's longest documented records of volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank. Source: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ 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 15-22 July. Incandescence at the summit was occasionally observed in overnight webcam images. Pulses of gas and ash were visible during 16-17 July and gray fumarolic plumes rose 300 m above the summit during 19-20 July. Diffuse plumes containing minor amounts of ash were observed during 20-21 July, along with avalanches of material that descended the Ceniza (SSW) drainage with ash rising along their paths. 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 16-22 July. Lava-flow advancement was concentrated at the SW lobe; a 16 July radar image showed 5 m of advancement and lobe inflation. 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 16-18 and 21-22 July. 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/ Home Reef | Tonga | 18.992°S, 174.775°W | Summit elev. -10 m The Tonga Geological Services reported no signs of activity at Home Reef during 5-19 July. A weak thermal anomaly in the crater was identified in a satellite image on 11 July. Discolored water around the island was visible in clear satellite images on 11 and 16 July. Yellowish sulfur deposits in and around the crater were visible in the 16 July image, but no fresh tephra deposits were noted. The dimensions of the crater remained unchanged and were estimated to be 210 m N-S and 120 m E-W. The Aviation Color Code remained at Yellow (the second lowest level on a four-level scale, the Maritime Alert Level remained at Orange (the third level on a four-level scale) with advice to stay at least 2 nautical miles (3.7 km) from the island, and the Alert Level for residents of Vavaâ??u and Haâ??apai remained at Green (the first level on a four-level scale). Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption. Source: Tonga Geological Services, Government of Tonga https://www.facebook.com/tongageologicalservice 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 16-22 July. Daily dense gray or white-to-gray ash plumes rose 200-600 m above the summit and drifted NE and SE. 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/ 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 11-17 July. A thermal anomaly over the volcano was identified in satellite images on 15 and 17 July; the volcano was quiet or weather conditions prevented views on the other days of the week. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC; specific events are in local time where noted. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php 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 16-22 July. Minor incandescence at the N vent and on the N vent cone was sporadic during 16-18 July. Slow slumping of the eruptive cone continued. After an hour of strong incandescence at the N vent late on 19 July, spattering began at 0355 on 20 July, followed soon after by low dome fountaining less than 30 m high. Lava overflowed the vent at around 0411. The dome fountains transitioned to vertical lava fountains that exceeded 60 m by 0515 and 100 m by 0525. The fountain was wide and comparatively shorter than during other recent fountaining episodes. Spattering and low fountaining started at the S vent at around 0600 and ended at noon. Throughout the day multiple lava flows advanced onto the crater floor and traveled as far as 2.5 km. The N vent ceased erupting at 1835, after 13 hours of sustained fountaining. The eruptive episode produced an estimated 7 million cubic meters of lava covering about 80 percent of the crater floor. Considerably less tephra was produced compared to recent episodes of lava fountaining. 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. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) https://volcanoes.usgs.gov/observatories/hvo/ Klyuchevskoy | Russia | 56.056°N, 160.642°E | Summit elev. 4754 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a bright thermal anomaly at Klyuchevskoy was identified in satellite images during 11 and 14-17 July. Weather conditions prevented observations during 12-13 July. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. 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://www.kscnet.ru/ivs/kvert/index_eng.php 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 16-22 July. White-to-gray ash plumes rose 200-500 m above the summit of the cone and drifted W, NW, and SE on most days; eruptive events were recorded on 18 July but not observed due to weather conditions. 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/ 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 16-23 July. At 1042 on 16 July a dense gray ash plume rose 1.2 km above the summit and drifted NE. At 1851 on 18 July a dense gray-to-brown ash plume rose 1 km above the summit and drifted NE. White plumes rose as high as 200 m and drifted NE and E on the other days. An eruptive event at 0723 on 23 July produced a dense white-and-gray ash plume that rose around 1.6 km and drifted SE. The eruptive event lasted for one minute and 18 seconds based on seismic data. 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/ 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 11-17 July. Earthquakes were around the same intensity compared to the previous week. The SW lava dome produced seven lava avalanches that traveled as far as 1.5 km SW down the Bebeng drainage, 18 that traveled as far as 1.8 km SW down the Krasak drainage, 44 that traveled as far as 2 km W down the Sat/Putih drainage, and one traveled 1.8 km W down the Batang drainage. 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/ Miyakejima | Japan | 34.094°N, 139.526°E | Summit elev. 775 m The Japan Meteorological Agency (JMA) reported that the number of small volcanic earthquakes beneath Miyakejimaâ??s summit had increased on 17 June but afterwards declined to a rate of a few per day. No changes in tilt were detected after 18 June. In addition, webcam camera observations and a field survey on 8 July revealed no significant changes in the topography, fumaroles, or geothermal conditions within the summit crater. At 1100 on 18 July the Alert level was lowered to 1 (on a 5-level scale) and the public was warned to be cautious within 500 m of the main crater. Geologic Summary. The circular, 8-km-wide island of Miyakejima forms a low-angle stratovolcano that rises about 1,100 m from the sea floor in the northern Izu Islands about 200 km SSW of Tokyo. The basaltic volcano is truncated by small summit calderas, one of which, 3.5 km wide, was formed during a major eruption about 2,500 years ago. Numerous craters and vents, including maars near the coast and radially oriented fissure vents, are present on the flanks. Frequent eruptions have been recorded since 1085 CE at vents ranging from the summit to below sea level, causing much damage on this small populated island. After a three-century-long hiatus ending in 1469 CE, activity has been dominated by flank fissure eruptions sometimes accompanied by minor summit eruptions. A 1.6-km-wide summit crater was slowly formed by subsidence during an eruption in 2000. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ Nevado del Ruiz | Colombia | 4.892°N, 75.324°W | Summit elev. 5279 m The Servicio Geológico Colombianoâ??s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued during 15-21 July, though weather conditions often obscured visual observations. Seismic data indicated that events associated with fluid movement slightly decreased in number and increased in intensity compared to the previous week, though were at low-to-moderate levels overall. Some of the seismic events were associated with pulsating ash emissions; webcam images confirmed these ash emissions, including some with higher-temperature ejecta. Gas and/or ash emissions generally rose as high as 400 m above the summit and drifted NW and WNW, though ash plumes at 1636 on 18 July, at 1738 on 19 July, and at 1245 on 20 July rose as high as 2.4 km above the summit. Ashfall was reported in Manizales (28 km NW) and Chinchiná (30 km WNW) during 18-19 July. The 19 July ash emission was observed by SGC scientists in the field and photographed by passengers on a commercial flight. Seismicity associated with rock fracturing decreased in number but increased in intensity compared to the previous week. The earthquakes were mainly located below Arenas Crater and the flanks within 12 km at depths of 1-6 km. Daily sulfur dioxide emissions had decreased compared to the previous week. The Alert Level remained at Yellow (the second level on a four-level scale). Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption. Source: Servicio Geológico Colombiano (SGC) https://www2.sgc.gov.co/volcanes/index.html Reventador | Ecuador | 0.077°S, 77.656°W | Summit elev. 3562 m The Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) reported that eruptive activity continued at Reventador during 15-22 July. Seismicity included 68-110 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Ash-and-gas plumes rose as high as 1.1 km above the crater rim and drifted mainly NW, ESE, and SE during 15-18 July. Webcams recorded multiple nightly instances of incandescent material descending the flanks as far as 1.1 km below the crater rim. Cloudy weather often obscured views. SecretarÃa de Gestión de Riesgos (SGR) maintained the Alert Level at Orange (the second highest level on a four-color scale). Geologic Summary. Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents. Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) http://www.igepn.edu.ec/; SecretarÃa de Gestión de Riesgos (SGR) http://www.gestionderiesgos.gob.ec/ Sangay | Ecuador | 2.005°S, 78.341°W | Summit elev. 5286 m The Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) reported that the eruption continued at Sangay during 15-22 July. The seismic network recorded 54-114 explosions each day. Ash-and-gas plumes were observed on most days in webcam and/or satellite images rising as high as 2.1 km above the summit and drifting mainly W, WSW, and SW, though weather clouds sometimes obscured views. During 20-21 July incandescent material was seen descending the NW flank as far as 1.2 km. SecretarÃa de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale). Geologic Summary. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within the open calderas of two previous edifices which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex. Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) http://www.igepn.edu.ec/; SecretarÃa de Gestión de Riesgos (SGR) http://www.gestionderiesgos.gob.ec/ 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 16-22 July, often with multiple daily eruptive events recorded by the seismic network. Daily dense white-and-gray or gray ash plumes rose 300-1,000 m above the summit and drifted N, W, SW, and S. Incandescence at the summit was visible in a few webcam images. 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 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 11-17 July. Thermal anomalies over the domes were identified in satellite images on 14 and 16 July; 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://www.kscnet.ru/ivs/kvert/index_eng.php 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 14-20 July. 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 around five events per hour, ejecting lapilli and bombs less than 150 m above the vents. Low-intensity explosions at the vents in Area C-S ejected ash above the vent at a rate of one event per hour. 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/; Dipartimento della Protezione Civile https://www.protezionecivile.gov.it/it/ 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 14-21July. Incandescence was observed nightly in webcam images. Explosions at 1620 and 1924 on 20 July, and at 0425 on 21 July, generated ash plumes that rose 400-900 m above the crater rim and drifted W and NW. 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). ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - https://volcano.si.edu/ IAVCEI - https://www.iavceivolcano.org/ To subscribe to the volcano list, send the message: subscribe volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx 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. 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