The Weekly Volcanic Activity Report: October 9 – 15, 2024
New activity/unrest was reported for 3 volcanoes from October 9 – 15, 2024. During the same period, ongoing activity was reported for 17 volcanoes.
Image credit: TW
New activity/unrest: Langila, Papua New Guinea | Spurr, United States | Taal, Philippines.
Ongoing activity: Aira, Japan | Dukono, Indonesia | Ebeko, Russia | Great Sitkin, United States | Ibu, Indonesia | Kanlaon, Philippines | Karymsky, Russia | Lewotobi, Indonesia | Manam, Papua New Guinea | Merapi, Indonesia | Sabancaya, Peru | Sangay, Ecuador | Semeru, Indonesia | Sheveluch, Russia | Stromboli, Italy | Suwanosejima, Japan | Villarrica, Chile.
New activity/unrest
Langila, Papua New Guinea
5.525°S, 148.42°E | Summit elev. 1330 m
The Darwin VAAC reported that an ash plume at Langila was identified in a satellite image at 0750 on 15 October rising to 1.8 km (6,000 ft) a.s.l. and drifting SW. The ash had dissipated by 0910.
Geological summary: Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower E flank of the extinct Talawe volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the N and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m.
Spurr, United States
61.299°N, 152.251°W | Summit elev. 3374 m
The Alaska Volcano Observatory (AVO) reported that low-level unrest at Spurr was ongoing. An extended outage of the seismic network occurred during February-April; elevated seismicity was already occurring when the network returned on 3 April. The rate of about 20 earthquakes per week and their magnitudes did not significantly change through mid-October . Over 900 located earthquakes were clustered in two areas; the earthquakes in one cluster were located at depths of 0-10 km beneath the volcano and those in the second cluster were located at depths of 20-35 km beneath an area SE of Crater Peak vent. The largest earthquake, a M 2.4, was recorded on 6 October. Inflation began to be detected in March by Global Navigation Satellite System (GNSS) stations on the flanks and has continued at a steady rate. A total of 4 cm of uplift was recorded by the stations closest to the source of deformation. The deformation was also confirmed in satellite radar data. A small lake formed in the summit crater sometime between 15 May and 15 June. During a 23 June overflight scientists observed the lake and estimated that it was approximately 3,800 square meters in area. Gas measurements detected low levels of sulfur dioxide and carbon dioxide at levels similar to the background levels measured in previous years. The summit crater lake grew to around 5,670 square meters by 18 September, was blue-green in color, and partially covered by ice. Active steaming was visible from vents along and above the NE lake shore and crater wall, and from a pit in the ice on the NE crater rim and had not changed in vigor during the current period of unrest.
The observations suggested that a new batch of magma had been emplaced beneath the volcano, with preliminary models indicating an area of pressurization at 3-5 km depth and about 3-4 km W of Spur. AVO noted that the current increase in earthquake activity has some similarities to past episodes of increased earthquake activity at Spurr. These periods include August 1991 to June 1992 that preceded the 1992 eruptions and 2004 to 2006 when increased earthquake activity accompanied an episode of heating at the summit that melted a substantial portion of the ice cap. 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).
Geological summary: Mount Spurr is the closest volcano to Anchorage, Alaska (130 km W) and just NE of Chakachamna Lake. The summit is a large lava dome at the center of a roughly 5-km-wide amphitheater open to the south formed by a late-Pleistocene or early Holocene debris avalanche and associated pyroclastic flows that destroyed an older edifice. The debris avalanche traveled more than 25 km SE, and the resulting deposit contains blocks as large as 100 m in diameter. Several ice-carved post-collapse cones or lava domes are present. The youngest vent, Crater Peak, formed at the southern end of the amphitheater and has been the source of about 40 identified Holocene tephra layers. Eruptions from Crater Peak in 1953 and 1992 deposited ash in Anchorage.
Taal, Philippines
14.0106°N, 120.9975°E | Summit elev. 311 m
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that phreatic eruptive events at Taal periodically continued during 8-15 October. There were 1-2 phreatic events recorded almost daily during the week, with most reportedly lasting 3-13 minutes long. Hot fluids upwelling in the lake were persistently observed, and daily steam-and-gas emissions that were sometime voluminous rose as high as 3 km above the crater rim. Two volcanic earthquakes were detected during 8-9 October, two periods of volcanic tremor lasting two minutes long were recorded during 9-10 October, one volcanic earthquake was recorded during 11-12 October, and a period of tremor lasting 10 hours and 30 minutes was recorded during 12-13 October. Sulfur dioxide emissions averaged 2,256 tonnes per day (t/d) on 9 October, 1,256 t/d on 12 October, and 2,064 t/d/ on 14 October, remaining at elevated levels. Vog was reported during 10-11 October. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited.
Geological 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.
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 Caldera’s Sakurajima volcano) during 7-14 October. Daily crater incandescence was visible in webcam images. An explosion at 0018 on 11 October generated an ash-and-gas plume that rose 400 m above the crater rim and merged into weather clouds. Ash-and-gas plumes from an explosion at 1242 on 13 October rose as high as 1.4 km above the crater rim and drifted NW. The explosion ejected large blocks 1-1.3 km from the vent. An eruptive event at 1344 on that same day produced an ash-and-gas plume that rose 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 stay 1 km away from both craters.
Geological 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.
Dukono, Indonesia
1.6992°N, 127.8783°E | Summit elev. 1273 m
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono was ongoing during 9-15 October. Daily dense gray-and-white ash plumes rose 100-800 m above the summit and drifted W. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.
Geological summary: Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia’s most active volcanoes. More-or-less 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 N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Ebeko, Russia
50.686°N, 156.014°E | Summit elev. 1103 m
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate explosive activity was ongoing at Ebeko during 4-10 October. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions on 4 October generated ash plumes that rose as high as 2 km (6,600 ft) a.s.l. and drifted S. Thermal anomalies were identified in satellite images on 4 October; on other days either no activity was observed, or weather conditions prevented views. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are UTC; specific events are in local time where noted.
Geological summary: The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters.
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 lava flow in Great Sitkin’s summit crater during 9-15 October. Continuing lava effusion was confirmed in satellite data on 12 October, by which time lava had filled most of the summit crater. The local seismic network continued to detect small earthquakes associated with the ongoing eruption. Weather clouds often obscured webcam and satellite views of the summit. 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).
Geological 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.
Ibu, Indonesia
1.488°N, 127.63°E | Summit elev. 1325 m
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 9-16 October. Daily gray or white-and-gray ash plumes that were sometimes dense generally rose 0.1-2 km above the summit and drifted NW, W, and SW; only white plumes were visible rising 100-200 m and drifting NE, SW, and W on 12 October. Some of the webcam images posted with the reports showed incandescence visible above the crater rim. At 0126 on 16 October an ash plume rose 4 km above the summit and drifted N and NE. 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.
Geological 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.
Kanlaon, Philippines
10.4096°N, 123.13°E | Summit elev. 2422 m
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Kanlaon during 8-15 October, characterized by elevated seismicity and sulfur dioxide emissions. The seismic network recorded 1-19 daily volcanic earthquakes. Daily gas-and-steam emissions that were often voluminous rose 400-750 m above the summit and drifted NE, SE, SW, and W. Sulfur dioxide emissions were recorded daily and continued to be high, averaging 1,919-6,011 tonnes/day. The Alert Level remained at 2 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone and warned pilots not to fly close to the volcano.
Geological summary: Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall.
Karymsky, Russia
54.049°N, 159.443°E | Summit elev. 1513 m
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported moderate levels of activity at Karymsky during 4-10 October. A thermal anomaly over the volcano was identified in satellite images during 3-7 October; the volcano was quiet or weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.
Geological 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.
Lewotobi, Indonesia
8.542°S, 122.775°E | Summit elev. 1703 m
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Lewotobi’s Laki-laki volcano continued during 9-15 October from a vent on the upper NW flank. Daily gray or white-and-gray ash plumes that were sometimes dense rose as high as 1 km above the summit and drifted SW, W, and NW. Incandescence at the vent was visible in a webcam image on 11 October. The Alert Level remained at 3 (the second highest level on a scale of 1-4) and the public was warned to stay outside of the exclusion zone, defined as a 3 km radius around both Laki-laki and Perempuan craters, 4 km to the NNW and SSE of Laki-laki.
Geological 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.
Manam, Papua New Guinea
4.08°S, 145.037°E | Summit elev. 1807 m
The Darwin VAAC reported that ash plumes from Manam were identified in satellite images during 10-13 October rising to 2.4 km (8,000 ft) a.s.l. and drifting NW, WNW, and W. The plumes were mostly continuous, though weather clouds sometimes obscured views.
Geological summary: The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country’s most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical basaltic-andesitic stratovolcano to its lower flanks. These valleys channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island’s shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most observed eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.
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 October. Seismicity was less intense compared to the previous week. The SW lava dome produced 200 lava avalanches that traveled as far as 1.7 km down the Bebeng drainage on the SW flank. Morphological changes to the SW lava dome resulting from continuing effusion and collapses of material. 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.
Geological 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.
Sabancaya, Peru
15.787°S, 71.857°W | Summit elev. 5960 m
The Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued during 7-13 October with a daily average of 11 explosions. Gas-and-ash plumes rose as high as 1.5 km above the summit and drifted less than 10 km SE and S. Thermal anomalies over the lava dome in the summit crater were identified in satellite data. Slight inflation was detected N of Hualca Hualca (7 km N). Sulfur dioxide emissions were at moderate levels, averaging 504 tons per day. The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay outside of a 12 km radius.
Geological summary: Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning “tongue of fire” in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of observed eruptions date back to 1750 CE.
Sangay, Ecuador
2.005°S, 78.341°W | Summit elev. 5286 m
The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that high levels of eruptive activity continued at Sangay during 8-15 October. The seismic network recorded 102-249 daily explosions during 8-12 October; there were no counts during the rest of the week due to data transmission problems. Gas-and-ash plumes visible in webcam and/or satellite images on most days rose as high as 1.6 km above the summit and drifted mainly W, WSW, and SW and occasionally to the NE. Weather conditions often obscured views, though several episodes of crater incandescence were observed during dark hours and incandescent material descended the SE drainage as far as 2 km. Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale).
Geological 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.
Semeru, Indonesia
8.108°S, 112.922°E | Summit elev. 3657 m
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Semeru during 9-15 October with multiple daily eruptive events recorded by the seismic network. Almost daily white-and-gray ash plumes that were sometimes dense rose 200-900 m above the summit and drifted in multiple directions; eruptive events were recorded on 9 October, but no emissions were observed. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.
Geological 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.
Sheveluch, Russia
56.653°N, 161.36°E | Summit elev. 3283 m
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that during 4-10 October lava extrusion may have continued at Sheveluch’s “300 years of RAS” dome on the SW flank of Old Sheveluch and at the dome at Young Sheveluch. Thermal anomalies over the domes were identified in satellite images during 4-8 and 10 October. Plumes of resuspended ash drifted 1,100 km SE and E during 3-4, 7-8, and 10 October. Weather conditions prevented views on the other days of the week. 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.
Geological 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.
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 7-13 October. Webcam images showed Strombolian activity at two 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-intensity explosions at a rate of 7-14 events per hour, ejecting lapilli and bombs less than 80 m above the vents. Spattering continued and was sometimes intense and continuous for long periods of time during 8-9 and 13 October. Explosions at the vents in Area C-S ejected tephra over 250 m above the vent. Intense spattering in Area N on 8 October was followed by the formation of a lava flow at around 1643 that descended the Sciara del Fuoco, stopping before the coastline. The lava flow was cooling and no longer active by 1930. Intense spattering again caused the overflow of lava the next day; at 1220 on 9 October lava flowed down the Sciara del Fuoco and again stopped before reaching the coastline; the flow was cooling by 1432. The Alert Level remained at Yellow (the second lowest level on a four-level scale).
Geological 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.
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 October. Crater incandescence was observed nightly in webcam images. Eruptive events at 0221 and 0750 on 7 October produced ash-and-gas plumes that rose 1.1-1.5 km above the crater rim; the plume from the second event drifted E. Ash-and-gas plumes were continuously emitted during 0943-1310, rose as high as 1.6 km above the crater rim, and drifted E. Ash-and-gas plumes from eruptive events at 0333 and 1540 on 10 October rose 1.3 km above the crater rim and drifted S and SE, respectively. Three eruptive events on 11 October, at 0403, 0737, and 1130, produced ash-and-gas plumes that rose 1-1.3 km straight up above the crater rim or drifted SE. An ash-and-gas plume from an eruptive event at 1352 on 13 October rose 1 km above the crater rim and drifted W. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Geological 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.
Villarrica, Chile
39.42°S, 71.93°W | Summit elev. 2847 m
On 11 October Servicio Nacional de Geología y Minería (SERNAGEOMIN) reported that low levels of activity were detected at Villarrica during 16-30 September, characterized as a decrease in the frequency of explosions with ejection of high-temperature tephra outside the crater. A webcam located near the volcano recorded only gas-and-steam emissions rising to low heights, up to a maximum of 120 m above the crater rim, though weather clouds often prevented observations. Seismicity was low. Sulfur dioxide emissions averaged 525 ± 93 tonnes per day (t/d), with a maximum daily average of 618 t/d recorded on 26 September; these values were at baseline levels. The Volcanic Alert Level was lowered to Green (the lowest level on a four-level scale). SENAPRED decreased the restricted zone around the crater to 500 m, with a “Preventative Early Warning“ status issued for the communities of Villarrica, Pucón (16 km N), Curarrehue, and Panguipulli.
Geological summary: The glacier-covered Villarrica stratovolcano, in the northern Lakes District of central Chile, is ~15 km south of the city of Pucon. A 2-km-wide caldera that formed about 3,500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesite cone at the NW margin of a 6-km-wide Pleistocene caldera. More than 30 scoria cones and fissure vents are present on the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano were produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Eruptions documented since 1558 CE have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged towns on its flanks.
References:
1 Smithsonian Institution / US Geological Survey – Weekly Volcanic Activity Report – October 9 – 15, 2024 – Managing Editor: Sally Sennert.
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