The Weekly Volcanic Activity Report: March 2 – 8, 2022

New activity/unrest was reported for 4 volcanoes between March 2 and 8, 2022. During the same period, ongoing activity was reported for 14 volcanoes.

New activity/unrest: Fuego, South-Central Guatemala | Kirishimayama, Kyushu (Japan) | Langila, New Britain (Papua New Guinea) | Manam, Northeast of New Guinea.

Ongoing activity: Davidof, Aleutian Islands (USA) | Descabezado Grande, Central Chile | Great Sitkin, Andreanof Islands (USA) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Merapi, Central Java | Pavlof, Alaska Peninsula, Alaska | Popocatepetl, Mexico | Santa Maria, Southwestern Guatemala | Semeru, Eastern Java | Semisopochnoi, Aleutian Islands (USA) | Sheveluch, Central Kamchatka (Russia) | Suwanosejima, Ryukyu Islands (Japan) | Wolf, Isla Isabela (Galapagos).

New activity/unrest

Fuego, South-Central Guatemala

14.473°N, 90.88°W, Summit elev. 3763 m

In a series of special bulletins, INSIVUMEH summarized increased activity at Fuego during 6-8 March that culminated in multiple pyroclastic flows and evacuations. A new period of effusion had begun on 5 March, resulting in a 300-m-long lava flow in the Ceniza drainage on the SSW flank. Explosions were weak to moderate in intensity, incandescent pulses were visible, and avalanches descended the Ceniza valley. Staff at the Observatorio Vulcanológico del Volcán de Fuego (OVFGO) in Panimaché I (8 km SW) noted that Strombolian activity intensified at around 1800 on 6 March. Incandescent material was ejected 200 m high and ash plumes rose along avalanches that traveled down the Ceniza and Trinidad (S) drainages. Rumbling sounds became more intense and frequent. By around 0930 on 7 March lava flows were 400 and 200 m long in the Ceniza and Santa Teresa (W) ravines, respectively. Incandescent material was ejected 100-200 m high and avalanches descended the Ceniza, Trinidad, and Santa Teresa.

By the afternoon activity again significantly increased based on both seismic and acoustic data as well as reports from observers at OVFGO and Observatorio Vulcanológico del Volcán de Agua (OVAGU). RSAM values increased just after 1200, peaking at a value just under 8,000, and notable pyroclastic flows were observed from OVFGO descending the Ceniza drainage at 1300. According to CONRED about 370 people were evacuated from Panimaché I and San Pedro Yepocapa (8 km NW). During the next hour larger, and more significant and frequent pyroclastic flows descended the Ceniza, sometimes spilling over the banks of the drainage. Ash fell in San Pedro Yepocapa and in other areas downwind. RSAM values decreased around 1400 but remained high. Pyroclastic flows continued to descend the drainage into the evening, and rumbling sounds, weak to moderate in intensity, were constantly audible. Weather clouds prevented clear views of the upper flanks. Ashfall was reported in Panimaché I and II, Morelia (9 km SW), Santa Sofía (12 km SW), Yucales, El Porvenir 8 km ENE), and Sangré de Cristo (8 km WSW). Between 1900-2200 RSAM values significantly increased and reached a peak value of around 14,000. Weather clouds cleared allowing for observations of the summit and upper flanks; pyroclastic flows continued to descend the Ceniza and avalanches and possible smaller pyroclastic flows traveled towards the Las Lajas drainage on the SE flank. A sulfur odor was reported in areas near the volcano and ash plumes drifted as far as 100 km NW and 40 km W and SW. Activity progressively declined during the morning of 8 March, with decreased effusion and eruption sounds; RSAM values declined by 0300 and remained low though 0735.

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.

Kirishimayama, Kyushu (Japan)

31.934°N, 130.862°E, Summit elev. 1700 m

JMA reported an increase in volcanic earthquakes just below Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group). A total of 17 events were recorded during 1-2 March, prompting JMA to raise the Alert Level to 2 (on a scale of 1-5) on 2 March. No changes were seen at the volcano during a field visit that same day. Volcanic earthquakes persisted, with 5-12 events per day recorded through 7 March. Emissions had risen no higher than 30 m above the crater rim since 1 January, and fumarolic plumes continued to rise no higher than 100 m from a fissure on the W flank. During a field survey conducted on 4 March at the base of the volcano, sulfur dioxide emissions were below the detectable limit and no changes to area hot springs were observed.

Geological 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.

Langila, New Britain (Papua New Guinea)

5.525°S, 148.42°E, Summit elev. 1330 m

The Darwin VAAC reported that on 6 March an ash plume from Langila rose 3 km (10,000 ft) a.s.l. and drifted SE. The plume had dissipated within an hour. On 8 March an ash plume rose to 3.7 km (12,000 ft) a.s.l. and drifted NW. Ash was no longer visible in satellite images within three hours.

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.

Manam, Northeast of New Guinea

4.08°S, 145.037°E, Summit elev. 1807 m

RVO reported that a small pyroclastic flow descending Manam’s flank was visually observed and recorded in webcam images at 0911 on 8 March. Minor ash emissions drifting NW were occasionally visible throughout the day. RSAM values sharply increased at 1900 coincident with escalating activity. An intense Strombolian phase at Southern Crater was observed during 1910-2030, characterized by loud roaring and rumbling heard on the mainland (22 km SW), bright summit incandescence, and ash emissions. The Alert Level was raised to Stage 3. The Darwin VAAC estimated that by 1950 the ash plume had risen as high as 15.2 km (50,000 ft) a.s.l. and drifted W. The plume had detached from the summit by 2050 and dissipated by 0050 on 9 March. Following the more intense eruptive phase, activity at Southern Crater was quiet and only white vapor emissions were visible. Observatory staff conducted a field visit the next day and noted no reports of roof collapses nor casualties in areas to the NW; vegetation including food crops were covered with ash.

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.

Ongoing activity

Davidof, Aleutian Islands (USA)

51.97°N, 178.33°E, Summit elev. 328 m

According to AVO the earthquake swarm that began on 24 January in the vicinity at Davidof continued at least through 8 March with a few small earthquakes recorded each day by seismometers on Little Sitkin (15 km E). The earthquakes were shallow (less than 10 km deep) and the largest recorded during the last 7-10 days was a M 3.9. The swarm was either related to tectonic processes or volcanic unrest. The volcano is also monitored by satellite and remote infrasound and lightning networks. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Geological summary: A cluster of small islands between Segula and Little Sitkin in the western Aleutians, the largest of which is Davidof, are remnants of a stratovolcano that collapsed during the late Tertiary, forming a 2.7-km-wide caldera. The islands include Khvostof, Pyramid, Lopy, and Davidof; the latter three form the eastern rim of the mostly submarine caldera, sometimes referred to as the “Aleutian Krakatau.” The islands were constructed above a roughly 100-m-deep submarine platform extending NW to Segula Island; the floor of the caldera lies 80 m below sea level. The islands are vegetated, but lava flows are recognizable, and Smith et al. (1978) suggested a possible Holocene age.

Descabezado Grande, Central Chile

35.58°S, 70.75°W, Summit elev. 3953 m

According to the Buenos Aires VAAC a diffuse cloud of resuspended ash from Descabezado Grande was visible in a satellite data on 8 March.

Geological summary: Volcán Descabezado Grande is a late-Pleistocene to Holocene andesitic-to-rhyodacitic stratovolcano with a 1.4-km-wide ice-filled summit crater. Along with Cerro Azul, only 7 km to the S, Descabezado Grande lies at the center of a 20 x 30 km volcanic field. A lateral crater, which formed on the upper NNE flank in 1932 shortly after the end of the major 1932 eruption from nearby Quizapu volcano on the N flank of Cerro Azul, was the site of the only historical eruption. The Holocene Alto de las Mulas fissure on the lower NW flank produced young rhyodacitic lava flows. Numerous small late-Pleistocene to Holocene volcanic centers are located N of the volcano. The northernmost of these, Lengua de Vulcano (or Mondaca), produced a very youthful rhyodacitic lava flow that dammed the Río Lentué.

Great Sitkin, Andreanof Islands (USA)

52.076°N, 176.13°W, Summit elev. 1740 m

AVO reported that slow lava effusion at Great Sitkin likely continued during 2-8 March and very low seismicity persisted. Elevated surface temperatures were periodically identified in satellite images. A possible steam plume rising above the weather clouds was visible during 4-5 March. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

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.

Karymsky, Eastern Kamchatka (Russia)

54.049°N, 159.443°E, Summit elev. 1513 m

KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 25-28 February. The volcano was obscured by clouds on the other days during 1-4 March. 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: 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.

Kilauea, Hawaiian Islands (USA)

19.421°N, 155.287°W, Summit elev. 1222 m

HVO reported that lava effusion at the vent of the main cone in the lower W wall of Kilauea’s Halema`uma`u Crater continued at variable rates during 2-8 March. After a brief pause effusion from the W vent resumed at about 0100 on 2 March and continued through 7 March. Lava from the vent traveled S and W, into the western active lava lake. Lava occasionally oozed out from the margins of the lake during 3-6 March, particularly along the E and N margins. A pause in effusion began in the evening of 7 March. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Geological 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.

Merapi, Central Java

7.54°S, 110.446°E, Summit elev. 2910 m

BPPTKG reported no significant morphological changes at Merapi’s summit lava dome during 25 February-3 March but there had been collapses at the SW dome, located just below the SW rim. Seismicity remained at high levels. As many as 73 lava avalanches traveled a maximum of 2 km down the Bebeng drainage on the SW flank. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-5 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.

Pavlof, Alaska Peninsula, Alaska

55.417°N, 161.894°W, Summit elev. 2493 m

AVO reported that the eruption at Pavlof was ongoing during 2-8 March. Small explosions were detected on most days. Lava effusion likely continued from a vent just E of the summit, possibly sending lava flows a short distance down the NE flank, though weather clouds often obscured views. Elevated surface temperatures were often identified in satellite images. A high-resolution satellite image acquired during 5-6 March showed a developing spatter cone in the E crater, as well as no active lava flows nor widespread ash deposits on the flanks. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Geological summary: The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.

Popocatepetl, Mexico

19.023°N, 98.622°W, Summit elev. 5393 m

During an overflight of Popocatépetl on 23 February, Instituto de Geofísica de la Universidad Nacional Autónoma de México (UNAM) and CENAPRED scientists noted that the inner crater dimensions were similar to those recorded in November 2021. The inner crater was 390-410 m in diameter and 160-200 m deep; the crater floor was covered in tephra and the remains of recent lava domes. Each day during 1-8 March there were 9-50 steam-and-gas emissions with diffuse ash rising from the crater and drifting W and NE. An explosion was recorded at 0959 on 4 March. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).

Geological summary: Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America’s 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time.

Santa Maria, Southwestern Guatemala

14.757°N, 91.552°W, Summit elev. 3745 m

INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 1-8 March. Incandescence from Caliente crater and the lava flows on the W and SW flanks was visible nightly. Avalanches generated by both lava effusion and collapsing material descended the W, SW, and S flanks, often reaching the base of the dome. Periodically the avalanches produced ash along their paths that fell on to the flanks or dissipated near the volcano.

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 W 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.

Semeru, Eastern Java

8.108°S, 112.922°E, Summit elev. 3657 m

PVMBG reported that the eruption at Semeru continued during 2-8 March, causing the observatory to issue several VONAs mostly for ash plumes. Ground observers noted an ash plume at 0540 on 3 March that rose vertically 4.2 km above the summit. At 2004 later that day a pyroclastic flow originating from the end of a lava flow descended the Kobokan drainage on the SE flank; an ash plume was not visible. Ash plumes at 0742 on 5 March, and at 0603 and 0734 on 6 March, rose 400-500 m above the summit and drifted N and NW. Ash plumes at 0534 and 0735 on 7 March rose 1 km and drifted SSE and NW, respectively. More ash plumes at 0541 and 0758 on 8 March rose 400 m and drifted SW and S. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, 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.

Semisopochnoi, Aleutian Islands (USA)

51.93°N, 179.58°E, Summit elev. 1221 m

AVO reported that low-level eruptive activity at Semisopochnoi’s North Cerberus cone continued during 1-8 March. Local seismic and infrasound instruments recorded daily small explosions. Weather clouds often prevented satellite and webcam views of the volcano, though explosions likely produced low ash clouds from the summit and they were visually confirmed during 4-8 March. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Geological summary: Semisopochnoi, the largest subaerial volcano of the western Aleutians, is 20 km wide at sea level and contains an 8-km-wide caldera. It formed as a result of collapse of a low-angle, dominantly basaltic volcano following the eruption of a large volume of dacitic pumice. The high point of the island is Anvil Peak, a double-peaked late-Pleistocene cone that forms much of the island’s northern part. The three-peaked Mount Cerberus was constructed within the caldera during the Holocene. Each of the peaks contains a summit crater; lava flows on the N flank of Cerberus appear younger than those on the south side. Other post-caldera volcanoes include the symmetrical Sugarloaf Peak SSE of the caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake in the NE part of the caldera. Most documented eruptions have originated from Cerberus, although Coats (1950) considered that both Sugarloaf and Lakeshore Cone could have been recently active.

Sheveluch, Central Kamchatka (Russia)

56.653°N, 161.36°E, Summit elev. 3283 m

KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 25 February-4 March. 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 1300 km3 volcano is one of Kamchatka’s largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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 eruption plumes at Suwanosejima’s Ontake Crater rose as high as 2.4 km during 28 February-7 March and blocks were ejected as far as 800 m from the crater. Three explosions were recorded and crater incandescence was visible nightly. Ashfall was reported in areas as far as 5 km from the vent including in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.

Geological summary: The 8-km-long, spindle-shaped 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. Suwanosejima, one of Japan’s most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical 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 horseshoe-shaped 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.

Wolf, Isla Isabela (Galapagos)

0.02°N, 91.35°W, Summit elev. 1710 m

IG reported that the eruption at Wolf continued during 1-8 March. Daily thermal alert counts, as many as 125, indicated active and advancing lava flows on the SSE flank.

Geological summary: Wolf, the highest volcano of the Galápagos Islands, straddles the equator at the north end of the archipelago’s largest island, Isabela. The 1710-m-high edifice has steeper slopes than most other Isabela volcanoes, reaching angles up to 35 degrees. A 6 x 7 km caldera, at 700 m one of the deepest of the Galápagos Islands, is located at the summit. A prominent bench on the west side of the caldera rises 450 above the caldera floor, much of which is covered by a lava flow erupted in 1982. Radial fissures concentrated along diffuse rift zones extend down the north, NW, and SE flanks, and submarine vents lie beyond the north and NW fissures. Similar unvegetated flows originating from a circumferential chain of spatter and scoria cones on the eastern caldera rim drape the forested flanks to the sea. The proportion of aa lava flows at Volcán Wolf exceeds that of other Galápagos volcanoes. An eruption in in 1797 was the first documented historical eruption in the Galápagos Islands.

Reference:

Global Volcanism Program, 2022. Report on Fuego (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 2 March-8 March 2022. Smithsonian Institution and US Geological Survey.