The Weekly Volcanic Activity Report: January 24 – 30, 2024

the weekly volcanic activity report

New activity/unrest was reported for 3 volcanoes from January 24 to 30, 2024. During the same period, ongoing activity was reported for 17 volcanoes

New activity/unrest: Ahyi, Mariana Islands (USA) | Lewotobi, Flores Island | Poas, Costa Rica.

Ongoing activity: Aira Kyushu, (Japan) | Bulusan, Luzon (Philippines) | Dukono, Halmahera | Ebeko, Paramushir Island (Russia) | El Misti, Peru | Erta Ale, Ethiopia | Fuego, South-Central Guatemala | Great Sitkin, Andreanof Islands (USA) | Lewotolok, Lembata Island | Marapi, Central Sumatra | Merapi, Central Java | Nevado del Ruiz, Colombia | Sabancaya, Peru | Santa Maria, Southwestern Guatemala | Sheveluch, Central Kamchatka (Russia) | Suwanosejima, Ryukyu Islands (Japan) | Ubinas, Peru.

New activity/unrest

Ahyi, Mariana Islands (USA)

20.42°N, 145.03°E; summit elev. -75 m

Signs of unrest at Ahyi Seamount continued. Plumes of discolored water extending as far as 19 km from the summit area were identified in satellite images during 23-26 January. Weather clouds obscured or mostly obscured views during the rest of the week. No volcanic activity was identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Geological summary: Ahyi seamount is a large conical submarine volcano that rises to within 75 m of the ocean surface ~18 km SE of the island of Farallon de Pajaros in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations.

Lewotobi, Flores Island

8.542°S, 122.775°E; summit elev. 1703 m

PVMBG reported that the eruption at Lewotobi’s Laki-laki volcano had decreased during 23-29 January based on visual and instrumental data. The lava flow on the NE flank continued to advance, reaching a length of 4 km, though the rate of advancement had slowed by 23 January, possibly due to gentler topography, a decrease in the effusion rate, or a combination of both. A total of 11 pyroclastic flows were detected and traveled 1-2 km N, NNE, and NE, though average distances were closer to 1 km. Eruption plume heights decreased from an average of 1.5 km above the summit to 500 m. The seismic network recorded a total of 388 lava avalanches that traveled as far as 1.5 km N and NE. Sulfur dioxide emissions significantly decreased, and deformation data indicated deflation. Analysis of deep volcanic earthquakes and low-frequency earthquakes both indicated a decrease in the supply of magma to the surface. At 1200 on 29 January the Alert Level was lowered to 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 4-km radius around Laki-laki Crater, 5 km to the NNE, and 6 km on the NE flanks.

Geological summary: The Lewotobi “husband and wife” twin volcano (also known as Lewetobi) in eastern Flores Island is composed of the Lewotobi Lakilaki and Lewotobi Perempuan stratovolcanoes. Their summits are less than 2 km apart along a NW-SE line. The conical Lakilaki has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has erupted only twice in historical time. Small lava domes have grown during the 20th century in both of the crescentic summit craters, which are open to the north. A prominent flank cone, Iliwokar, occurs on the E flank of Perampuan.

Poas, Costa Rica

10.2°N, 84.233°W; summit elev. 2697 m

OVSICORI-UNA reported that at 0546 on 25 January a small phreatic eruption at Poás produced a steam plume that rose more than 500 m high and drifted W. The event produced the tallest plume recorded since 30 September 2019. According to the Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE) the event resulted in the restriction of the number of people that can be on the viewing platform to 56 at a time and visitors were required to wear hardhats. At 1437 on 26 January a more significant phreatic eruption ejected material 300 m above the lake’s surface and produced a gas-and-steam plume that rose 700 m high. During 26-27 January near constant degassing manifested as bubbling in the lake was observed.

Geological 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.

Ongoing activity

Aira Kyushu, (Japan)

31.5772°N, 130.6589°E; summit elev. 1117 m

JMA reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 22-29 January with nighttime crater incandescence. An eruptive event at 0014 on 27 January produced an ash plume that rose 1.1 km above the crater rim and drifted S. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 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.

Bulusan, Luzon (Philippines)

12.769°N, 124.056°E; summit elev. 1535 m

In a special advisory, PHIVOLCS reported increased seismicity at Bulusan, characterized by a total of 126 volcanic-tectonic earthquakes recorded by the seismic network during 0000-2145 on 28 January. The events had magnitudes of 0.3-2.2 and were located at depths of 1-9 km beneath the N and NW flanks. Weak-to-moderate gas emissions rose from the summit crater and active vents, which drifted SW and NW. The Alert Level remained at 1 (the second level on a scale of 0-5) and PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to be vigilant within the 2-km Extended Danger Zone (EDZ) on the SE flank.

Geological summary: Luzon’s southernmost volcano, Bulusan, was constructed along the rim of the 11-km-diameter dacitic-to-rhyolitic Irosin caldera, which was formed about 36,000 years ago. It lies at the SE end of the Bicol volcanic arc occupying the peninsula of the same name that forms the elongated SE tip of Luzon. A broad, flat moat is located below the topographically prominent SW rim of Irosin caldera; the NE rim is buried by the andesitic complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded since the mid-19th century.

Dukono, Halmahera

1.6992°N, 127.8783°E; summit elev. 1273 m

PVMBG reported that the eruption at Dukono was ongoing during 24-30 January. Gray-and-white ash plumes rose 100-1,500 m above the summit and drifted S on 25 and 29 January; emissions were not observed on the other days. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-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, Paramushir Island (Russia)

50.686°N, 156.014°E; summit elev. 1103 m

KVERT reported that moderate explosive activity was ongoing at Ebeko during 18-25 January. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 21-22 January generated ash plumes that rose as high as 3 km (10,000 ft) a.s.l and drifted NE and W. 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.

El Misti, Peru

16.294°S, 71.409°W; summit elev. 5822 m

Instituto Geofísico del Perú (IGP) reported that lahars descended the SE flanks at El Misti at 1448 on 23 January and at 1642 on 25 January. The report noted that possible areas of impact included the Andamayo and Agua Salada river drainages in the Chiguata District. The public was warned to stay away from the drainages and roads on the SE flank.

Geological summary: El Misti is a symmetrical andesitic stratovolcano with nested summit craters that towers above the city of Arequipa, Peru. The modern symmetrical cone, constructed within a small 1.5 x 2 km wide summit caldera that formed between about 13,700 and 11,300 years ago, caps older Pleistocene volcanoes that underwent caldera collapse about 50,000 years ago. A large scoria cone has grown with the 830-m-wide outer summit crater. At least 20 tephra-fall deposits and numerous pyroclastic-flow deposits have been documented during the past 50,000 years, including a pyroclastic flow that traveled 12 km to the south about 2000 years ago. The most recent activity has been dominantly pyroclastic, and strong winds have formed a parabolic dune field of volcanic ash extending up to 20 km downwind. An eruption in the 15th century affected nearby Inca inhabitants. Some reports of historical eruptions may represent increased fumarolic activity.

Erta Ale, Ethiopia

13.601°N, 40.666°E; summit elev. 585 m

During 13-23 January lava flows emerged from vents in Erta Ale’s S pit crater and traveled about 500 m S, 200 m NW, and 250 m SSW based on satellite images. Visitors to the volcano took photographs and video of low lava fountaining at a cone and advancing pahoehoe flows. Activity increased notably during the morning of 27 January.

Geological 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.

Fuego, South-Central Guatemala

14.473°N, 90.88°W; summit elev. 3763 m

INSIVUMEH reported that eruptive activity continued at Fuego during 23-31 January. Explosions were recorded daily, averaging 2-9 per hour on most days when counts were reported; daily reports were not available on 29 and 30 January. The explosions generated gas-and-ash plumes that rose as high as 1.2 km above the crater rim and drifted as far as 30 km in multiple directions. Explosions caused frequent block avalanches that descended various drainages including the Ceniza (SSW), Seca (W), Taniluyá (SW), and Las Lajas (SE) and reached vegetated areas. The explosions also ejected incandescent material 100-400 m above the summit on most of the days. Ashfall was reported during 25-26 and 27-28 January in areas downwind including Yepocapa (12 km SW), Panimache I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), Finca Asuncion (12 km SW), La Rochela (8 km SSW), Finca Ceilán (9 km S), and San Andrés. Ashfall was forecasted to fall in communities to the N, NW, SW, and S on the other days. Weak rumbling sounds and shock waves were frequently reported.

Geological 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 historical 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.

Great Sitkin, Andreanof Islands (USA)

52.076°N, 176.13°W; summit elev. 1740 m

AVO reported that the eruption of lava at Great Sitkin’s summit lava dome continued during 24-30 January, confirmed by satellite data acquired during the week. Effusion was concentrated at the center of the dome with minimal advancement at the margins of the flow. The center of the dome uplifted and caused radial cracks; a new lobe of lava extruded from the northernmost crack and traveled 180 m NW of the vent by 24 January. Weakly elevated surface temperatures were identified in satellite data during 24-26 January. Cloudy weather sometimes prevented satellite views of the volcano. Local webcams and seismic data communications that were offline due to a storm-related power failure came back online on 28 January; infrequent, small volcanic earthquakes were detected during 29-30 January. The Volcano Alert Level remained at Watch (the third highest level on a four-level scale) and the Aviation Color Code remained at Orange (the third highest color on a four-color scale).

Geological summary: The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger parasitic volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an ancestral volcano and produced a submarine debris avalanche. Deposits from this and an older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Historical eruptions have been recorded since the late-19th century.

Lewotolok, Lembata Island

8.274°S, 123.508°E; summit elev. 1431 m

PVMBG reported that the eruption at Lewotolok continued during 24-30 January. White gas-and-steam plumes rose 50-100 m above the summit and drifted NE, E, and SE on 27 and 29 January. White-and-gray plumes rose 50-200 m above the summit and drifted SE on 28 January. Emissions were not visible on the other days. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay at least 2 km away from the summit crater.

Geological 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.

Marapi, Central Sumatra

0.38°S, 100.474°E; summit elev. 2885 m

PVMBG reported that eruptive activity at Marapi (on Sumatra) was ongoing during 24-30 January. White-and-gray ash plumes rose 300 m above the summit and drifted N and NE on 25 January. White gas-and-steam plumes rose 150-250 m above the summit and drifted in multiple directions during 28-30 January. Emissions were not observed on the other days. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 4.5 km away from the active crater.

Geological 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.

Merapi, Central Java

7.54°S, 110.446°E; summit elev. 2910 m

BPPTKG reported that the eruption at Merapi (on Java) continued during 19-25 January. Seismicity remained at high levels. The SW lava dome produced a total of 47 lava avalanches that traveled as far as 1.5 km SW down the upper part of the Bebeng drainage. A total of 19 pyroclastic flows descended the Bebeng drainage as far as 3 km. The pyroclastic flows removed material from the upper parts of the Bebeng and Krasak drainages. According to news articles, minor ashfall was reported in Jelok Village (40 km S) at around 0845 on 21 January. An eruptive event with pyroclastic flows at 1355 that same day produced an ash plume that rose 1 km above the summit and caused ashfall in areas within 17 km SE, E, and NE, though some of the villages were located at greater distances. Minor amounts of ash fell in areas downwind, including Kemalang (15 km SE), Klaten (32 km SE), Selo Districts, Musuk, Boyolali (17 km E), Cepogo (4 km NE), Musuk (11 km ESE), Tamansari, Boyolali Kota, Teras (22 km E), Mojosongo (45 km E), and Sambi (28 ENE) at around 1430. The ash was washed away quickly due to rain. BPPTKG noted that morphological changes to the SW lava dome identified in webcam images were due to continuing 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.

Nevado del Ruiz, Colombia

4.892°N, 75.324°W; summit elev. 5279 m

Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued at low levels during 23-29 January. Seismic events indicating rock fracturing increased in number, though the intensity of the signals was similar to the previous week. These events were mainly located in areas up to 6 km to the NE and SSE of Arenas Crater, and at depths of 1-7 km. The largest event, a M 1.3, occurred at 2105 on 24 January and was located about 1 km SSE of the crater and at a depth of 3 km. Seismicity associated with gas-and-ash emissions remained at similar numbers as the previous week but were less intense. Gas-and-ash emissions drifted NW and N and rose to a maximum height of 1.8 km above the summit, recorded on both 25 and 29 January. Sulfur dioxide emissions varied but decreased overall. The Alert Level remained at Yellow, Level III (the second level on a four-level scale), and the public was warned to stay out of the restricted areas around Arenas Crater.

Geological 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.

Sabancaya, Peru

15.787°S, 71.857°W; summit elev. 5960 m

Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued at moderate levels during 22-28 January with a daily average of 47 explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted less than 10 km NW and W. Thermal anomalies over the lava dome in the summit crater were identified in satellite data. Slight inflation was detected near the Hualca Hualca sector (4 km N). The Alert Level remained at Orange (the third level on a four-color scale) and the public were 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 historical eruptions date back to 1750.

Santa Maria, Southwestern Guatemala

14.757°N, 91.552°W; summit elev. 3745 m

INSIVUMEH reported that eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 23-31 January with a lava extrusion at the Caliente dome. Daily reports were not available on 29 and 30 January. Incandescence from the dome was visible during most nights and early mornings. Explosions occurring at a rate of 1-6 per hour on most days generated gas-and-ash plumes that rose 600-900 m above the dome and drifted mainly NW, W, and SW. The explosions produced block avalanches on the dome’s W, SW, S, and E flanks and generated occasional, short-range pyroclastic flows that predominantly descended the W, SW, and S flanks. Block avalanches were visible? from the margins of the upper part of the lava flow on the WW flank. Ashfall occurred in Loma Linda (7 km W) and San Marcos Palajunoj (8 km SW) during 25-26 January.

Geological summary: Symmetrical, forest-covered Santa María 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.

Sheveluch, Central Kamchatka (Russia)

56.653°N, 161.36°E; summit elev. 3283 m

KVERT reported that the eruption at Sheveluch continued during 18-25 January. A thermal anomaly was identified in satellite images during 20-25 January; 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: 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.

Suwanosejima, Ryukyu Islands (Japan)

29.638°N, 129.714°E; summit elev. 796 m

JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 22-29 January. A total of 15 explosions were recorded during the week, with 1-4 occurring each day. Ash plumes rose as high as 1 km above the crater rim and drifted SE and E, and large blocks were ejected as far as 400 m from the vent. Crater incandescence was observed in webcam images nightly and rumbling was occasionally heard in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 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 historically active summit craters. The summit is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. 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 blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating the open Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.

Ubinas, Peru

16.355°S, 70.903°W; summit elev. 5672 m

Instituto Geofísico del Perú (IGP) reported that lahars descended the Volcánmayo drainage on the SE flank at Ubinas at 1910 on 23 January, at 2015 on 25 January, and at 1540 on 27 January. The report noted that the lahars traveled towards the Ubinas River and could possibly impact the Districts of Ubinas, Matalaque, and population centers. The public was warned to stay away from the drainage and to avoid driving on the Querapi-Ubinas-Huarina highway. Daily gas-and-steam plumes rose 100-500 m above the summit and drifted in multiple directions during 24-30 January.

Geological summary: A small, 1.4-km-wide caldera cuts the top of Ubinas, Perú’s most active volcano, giving it a truncated appearance. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front. The growth and destruction of Ubinas I was followed by construction of Ubinas II beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank about 3,700 years ago extend 10 km from the volcano. Widespread Plinian pumice-fall deposits include one of Holocene age about 1,000 years ago. Holocene lava flows are visible on the flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.

References:

1 Smithsonian Institution / US Geological Survey – Weekly Volcanic Activity Report, 24 January-30 January 2024 – Managing Editor: Sally Sennert

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We value the thoughts and opinions of our readers and welcome healthy discussions on our website. In order to maintain a respectful and positive community, we ask that all commenters follow these rules:

  • Treat others with kindness and respect.
  • Stay on topic and contribute to the conversation in a meaningful way.
  • Do not use abusive or hateful language.
  • Do not spam or promote unrelated products or services.
  • Do not post any personal information or content that is illegal, obscene, or otherwise inappropriate.

We reserve the right to remove any comments that violate these rules. By commenting on our website, you agree to abide by these guidelines. Thank you for helping to create a positive and welcoming environment for all.

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