The Weekly Volcanic Activity Report: June 5 - 11, 2024

New activity/unrest was reported for 8 volcanoes from June 5 to 11, 2024. During the same period, ongoing activity was reported for 12 volcanoes.

New activity/unrest

Bezymianny, Central Kamchatka (Russia)

55.972°N, 160.595°E | Summit elev. 2882 m

KVERT reported that a daily thermal anomaly over Bezymianny was identified in satellite images during 31 May-6 June. According to the Tokyo VAAC an ash plume was identified in satellite images at 1350 (local time) on 5 June rising to 5.5 km (18,000 ft) a.s.l. and drifting E. The ash plume had dissipated by 1720 (local time). Dates are UTC; specific events are in local time where noted.

Geological summary: The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.

Ibu, Halmahera

1.488°N, 127.63°E | Summit elev. 1325 m

PVMBG reported that the eruption at Ibu continued during 5-11 June with occurrences of tall ash plumes. White, gray, and black ash plumes rose as high as 5 km above the crater rim and drifted in multiple directions during 5-6 and 9 June. White steam-and-gas plumes rose 200-1,000 m above the crater rim and drifted in multiple directions during on 29 May and 3 June. White-and-gray ash plumes rose as high as 4 km and drifted in multiple directions on 11 June. The Alert Level remained at 4 (the highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 7 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

10.412°N, 123.132°E | Summit elev. 2435 m

PHIVOLCS reported that intense rain on 6 June mobilized ash deposited during the 3 June eruption at Kanlaon causing lahars to descend the S flank and impact local communities. The lahars began at around 1300 and lasted 25 minutes based on seismic data. They deposited cohesive gray mud, plant debris, and gravel in at least four stream channels including Tamburong Creek, which courses through Biak-na-bato and Calapnagan, La Castellana; Intiguiwan River in Guinpanaan and upstream Baji-Baji Falls in Cabacungan, La Castellana; Padudusan Falls, Masulog, Canlaon City; and the Binalbagan River, which drains the S flank of the volcano. Lahars overflowed parts of Tamburong Creek and deposited material a few centimeters thick along a section of the main road in Biak-na-Bato, making it impassable to motorists. Thunderstorms continued and channel-confined lahars on the S and W flank were detected the next day. The lahars began at around 1450 on 7 June and lasted 80 minutes based on seismic data. They were described as cohesive and cement-like and carried tree debris along the Baji-Baji Falls and Ibid Creek, in Cabacungan, La Castellana. Lahars also descended the Santo Guintubdan, Ara-al, La Carlota City and muddy waters were observed in the Buslugan, Busay Oro, Busay Abaga, Busay Mayor, Busay Kapid, Kabkaban, Ezzy, Busay Ambon, and Labi Labi falls. Voluminous gas-and-steam emissions rose 1.5-2 km above the summit and drifted NE and SW during 6-8 June.

A special notice was issued on 8 June due to elevated sulfur dioxide levels. During a field survey sulfur dioxide flux averaged of 4,397 tonnes per day (t/d) which was the highest level recorded so far this year and the second highest land-based measurement for Kanlaon. Sulfur dioxide emissions were elevated in 2024, averaging 1,458 t/d, though after the 3 June eruption the daily average increased to 3,347 t/d. Emisisons had decreased on 9 June, averaging 3,304 t/d. The rate of volcanic earthquakes persisted at above-background levels with an average of 33 events per day. Moderate steam-and-gas emissions rose 300-500 m above the summit and drifted NE and SW during 9-11 June. At least 1,237 families or 4,190 residents of five barangays remained in evacuation shelters according to a 12 June news article; many had health problems from exposure to sulfur dioxide gas and ash. 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.

Geological summary: Kanlaon volcano (also spelled Canlaon) forms the highest point on the island of Negros, Philippines. 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.

Kilauea, Hawaiian Islands (USA)

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

HVO lowered the Volcano Alert Level for Kilauea to Advisory and the Aviation Color Code to Yellow on 5 June, noting that the fissure eruption that had occurred in a remote area along the Southwest Rift Zone on 3 June was unlikely to restart. Tremor, degassing, and incandescence associated with the fissure vents had substantially decreased. A sulfur dioxide emission rate of 5,500 tonnes per day (t/d) was measured at the eruption site on 4 June, well above background levels (100 t/d or less). Sulfur dioxide emissions decreased to 400 t/d on 6 June and likely continued to decline over subsequent days. Lava flows only covered about 350,000 square meters (0.35 square kilometers). Incandescence from the flow field was visible in webcam images, but decreased daily and was no longer visible by 10 June.

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.

Lewotobi, Flores Island

8.542°S, 122.775°E | Summit elev. 1703 m

PVMBG reported that eruptive activity at Lewotobi’s Laki-laki volcano increased during 26 May-9 June. Eruptive activity increased daily, and ash-and-steam plumes became taller, rising 100-900 m above the summit on average and drifting in multiple directions; dense ash emissions rose 1-1.1 km above them summit on 5 and 9 June. The number of volcanic earthquakes as well as earthquake signals indicating eruptive events and avalanches significantly increased. PVMBG noted that there was also a significant increase in other types of seismic signals, though those increases were unrelated to the eruption; repairs and changes to the seismic network resulted in better detection of seismic signals. Incandescence at the summit was visible in a 5 June webcam image, and Strombolian activity was periodically visible on 9 June. At 0900 on 10 June the Alert Level was raised to 3 (the second lowest 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 Laki-laki crater, 4 km to the NNE, and 5 km on the NE flanks. Strombolian activity continued on 10 June and several ash emissions rose 600-1,000 m above the summit. Gray ash emissions rose 300-600 m above the summit and drifted SW and W on 11 June.

The lava flows on the NE flank advanced 20 m during 29 February-9 April to a total length of 4.34 km; the advancement was due to gravitational forces and not eruptive activity, and no additional advancement had been recorded since.

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.

Reykjanes, Reykjanes Peninsula

63.817°N, 22.717°W | Summit elev. 140 m

IMO reported that the eruption that began on 29 May near Sundhnúk, NE of Sýlingarfell, within the Reykanes volcanic system, continued through 11 June. The lava field had an estimated area of 8.6 square kilometers and the erupted volume was about 36 million cubic meters based on a 3 June drone survey. The estimated flow rate during 29 May-3 June was 30 cubic meters per second. Only one crater was active by the morning of 4 June, and the flow rate had likely decreased. Lava flows advanced NW towards Sýlingarfell and S towards Hagafell on 5 June. On 7 June flows continued to advance N towards Sýlingarfell, causing the flow field in that area to thicken, and continued on expand N and W. Deformation data indicated that deflation had ceased. A small collapse of the crater wall was visible according to a news source. The rate of lava advancement increased during 7-8 June in an area N of Sýlingarfell, towards Grindavíkurvegur. By 1030 on 8 June lava had crossed Grindavík road just to the N of where work was being done to close a gap in an earthen barrier. Lava also moved along the barrier and in some areas flowed over the top. The flows had slowed by noon, reaching 800 m from hot water pipelines. Inflation began to be detected sometime during 8-9 June though the rate of uplift had not been determined. The eruption continued during 9-11 June. Lava continued to accumulate in a lava pond just SE of Sýlingarfell. Notable sulfur dioxide pollution from the eruption was measured in many parts of Reykjavík and in the W part of South Iceland. Vog was noticeable in the W part of the country during the morning of 11 June.

Geological summary: The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial basaltic crater rows and small shield volcanoes. The submarine Reykjaneshryggur volcanic system is contiguous with and is considered part of the Reykjanes volcanic system, which is the westernmost of a series of four closely-spaced en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of the subaerial part of the system (also known as the Reykjanes/Svartsengi volcanic system) is covered by Holocene lavas. Subaerial eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system, and numerous submarine eruptions dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Basaltic rocks of probable Holocene age have been recovered during dredging operations, and tephra deposits from earlier Holocene eruptions are preserved on the nearby Reykjanes Peninsula.

San Cristobal, Sierra de los Marrabios

12.702°N, 87.004°W | Summit elev. 1745 m

The Washington VAAC reported that ash plumes from San Cristóbal were visible in webcam images at around 1500 and 1700 on 7 June rising above the summit and drifting N. The plumes were not identified in satellite images due to weather conditions. According to a news report the ash plume rose 1 km above the summit.

Geological summary: The San Cristóbal volcanic complex, consisting of five principal volcanic edifices, forms the NW end of the Marrabios Range. The symmetrical 1745-m-high youngest cone, named San Cristóbal (also known as El Viejo), is Nicaragua’s highest volcano and is capped by a 500 x 600 m wide crater. El Chonco, with several flank lava domes, is located 4 km W of San Cristóbal; it and the eroded Moyotepe volcano, 4 km NE of San Cristóbal, are of Pleistocene age. Volcán Casita, containing an elongated summit crater, lies immediately east of San Cristóbal and was the site of a catastrophic landslide and lahar in 1998. The Plio-Pleistocene La Pelona caldera is located at the eastern end of the complex. Historical eruptions from San Cristóbal, consisting of small-to-moderate explosive activity, have been reported since the 16th century. Some other 16th-century eruptions attributed to Casita volcano are uncertain and may pertain to other Marrabios Range volcanoes.

Taal, Luzon (Philippines)

14.0106°N, 120.9975°E | Summit elev. 311 m

In a special report, PHIVOLCS noted that sulfur dioxide emissions were elevated at Taal, averaging 11,072 tonnes per day (t/d) on 6 June. Sulfur dioxide emissions have been continuously released since 2021 and averaged 8,294 t/d during 2024. Hazy or voggy conditions were reported at Alitagtag, Tingloy, San Nicolas, Laurel, Taysan, Lobo, and Batangas City, and were observed during field surveys in Agoncillo, Lemery, Taal, Santa Teresita, Alitagtag, Cuenca, Lipa, Balete, and Malvar.

Daily steam-and-gas emissions that were sometimes voluminous rose 1.9-2.4 km above the rim of Main Crater and drifted NNW, NW, SW, and SSE based on webcam images during 6-11 June. Two volcanic earthquakes were recorded during the week. During 7-8 June there were five periods of volcanic tremor lasting as short as three minutes and as long as 10 hours and eight minutes. A two-minute phreatic event was also recorded. Upwelling gases and hot fluids in the lake were observed during 8-10 June. Sulfur dioxide emissions averaged 2,470 t/d on 10 June. 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 to take extra precaution around Main Crater and along the Daang Kastila fissure.

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, 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 27 May-3 June with nighttime crater incandescence. Sulfur dioxide emissions were high, averaging 2,000 tons per day on 30 May. 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, Halmahera

1.6992°N, 127.8783°E | Summit elev. 1273 m

PVMBG reported that the eruption at Dukono was ongoing during 5-11 June. Gray-and-white ash plumes rose 100-1,600 m above the summit and drifted E and W on most days; no emissions were observed on 7 June. 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, Paramushir Island (Russia)

50.686°N, 156.014°E | Summit elev. 1103 m

KVERT reported that moderate explosive activity was ongoing at Ebeko during 30 May-6 June. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 31 May and 1-2 June generated ash plumes that rose as high as 2 km (6,600 ft) a.s.l. and drifted SE and S. A thermal anomaly was identified in satellite images on 30 May, 1 June, and 3 June; 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, Andreanof Islands (USA)

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

AVO reported that slow lava effusion in Great Sitkin’s summit crater continued during 5-11 June. Seismicity was low with few daily small earthquakes. Slightly elevated surface temperatures at the summit were identified in satellite images during 4-6 June and diffuse steam emissions were visible in webcam images during 5-6 June. Weather clouds sometimes obscured satellite and webcam views. 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.

Lewotolok, Lembata Island

8.274°S, 123.508°E | Summit elev. 1431 m

PVMBG reported that the eruption at Lewotolok continued during 5-11 June. Daily white steam-and-gas plumes rose as high as 600 m above the summit and drifted multiple directions. On 11 June white-and-gray ash plumes rose 100-400 m and drifted W and E. Summit incandescence and incandescent material being ejected at the summit were visible in webcam images during the week. The Alert Level remained at 3 (on a scale of 1-4) and visitors and residents of Lamawolo, Lamatokan, and Jontona were warned to stay 2 km away from the vent and 3 km away from the vent on the S and SE flanks.

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 5-11 June. White gas-and-steam plumes rose 200-300 m above the summit and drifted in multiple directions during 5-6 and 8 June. White-and-gray ash plumes rose 300-750 m above the summit and drifted multiple directions during 7 and 9-10 June. One of the ash plumes, recorded at 0810 on 9 June, was gray-to-brown and rose 300 m and drifted SE. Emissions were not visible on 11 June. 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 31 May-6 June. Seismicity had decreased compared to the previous week. The SW lava dome produced 141 lava avalanches that traveled as far as 1.9 km down the upper part of the Bebeng drainage on the SW flank. Three pyroclastic flows also descended the Bebeng, traveling as far as 1 km. Morphological changes to the SW lava dome were due to continuing effusion and collapses of material. The volume of the SW dome was an estimated 2,335,200 cubic meters and the dome in the main crater was stable at an estimated 2,362,800 cubic meters based on a 6 June drone survey. The highest temperature of the SW dome was around 243 degrees Celsius, lower than the previous measurement. 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.

Nyiragongo, DR Congo

1.52°S, 29.25°E | Summit elev. 3470 m

Thermal anomalies on Nyiragongo’s crater floor were identified in satellite images on 31 May and 5 June.

Geological summary: The Nyiragongo stratovolcano contained a lava lake in its deep summit crater that was active for half a century before draining catastrophically through its outer flanks in 1977. The steep slopes contrast to the low profile of its neighboring shield volcano, Nyamuragira. Benches in the steep-walled, 1.2-km-wide summit crater mark levels of former lava lakes, which have been observed since the late-19th century. Two older stratovolcanoes, Baruta and Shaheru, are partially overlapped by Nyiragongo on the north and south. About 100 cones are located primarily along radial fissures south of Shaheru, east of the summit, and along a NE-SW zone extending as far as Lake Kivu. Many cones are buried by voluminous lava flows that extend long distances down the flanks, which is characterized by the eruption of foiditic rocks. The extremely fluid 1977 lava flows caused many fatalities, as did lava flows that inundated portions of the major city of Goma in January 2002.

Reventador, Ecuador

0.077°S, 77.656°W | Summit elev. 3562 m

In a special report issued on 10 June IG-EPN reported that the number and amplitude of explosions at Reventador had increased beginning on 21 March and remained elevated, based on seismic data. Additionally, during this period a slight increase in sulfur dioxide emissions was identified in satellite data. The daily explosion count peaked on 26 May and again on 9 June. IG noted that the characteristics of the ash emissions had not changed and remained at normal levels with plumes typically rising 1 km above the crater rim; plumes to 1.6 km indicate higher activity, and 2 km is considered notable. Since 2 May morphological changes in the crater area reflected the generation of small pyroclastic flows that descended the S and SE flanks but did not impact residents or infrastructure. Explosive activity during 2-3 June created a small ravine on the SSE flank and a 125-m-wide depression at the crater rim, at the head of the ravine. Incandescence at the SE part of the crater became visible and persisted. Subsequent pyroclastic flows were channeled down the ravine, reaching the base of the cone.

During 1-6 June the Washington VAAC issued 584 reports of ash emissions, or an average of two reports per day, according to IG. The plumes rose 400-2,800 m above the crater rim, averaging 1 km high. There were 62-85 daily explosions during 7-11 June. Weather clouds prevented views during 7-9 June. Ash plumes during 10-11 June rose 700-800 m and drifted WNW and NW.

Geological summary: Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.

Semeru, Eastern Java

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

PVMBG reported that eruptive activity continued at Semeru. Continuous tiltmeter and GPS data showed that inflation was detected in May and seismic data showed that magma continued to rise to the surface. During 5-11 June white-and-gray ash plumes that were sometimes dense rose 300-800 m above the summit and drifted S and SW on all days except for 7 June. Several additional daily eruptive events were recorded by the seismic network, though plumes were not visually confirmed. During 0000-0600 on 10 June there were 28 lava avalanches that descended the Kobokan drainage as far as 2.5 km. The Alert Level remained at 3 (the third highest 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, Central Kamchatka (Russia)

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

KVERT reported that thermal anomalies over both the new and older lava domes at Sheveluch were identified in satellite images during 1-2 and 4-6 June; the domes were obscured by weather clouds on 31 May and 3 June. 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 eruptive activity at Suwanosejima’s Ontake Crater continued during 3-10 June and produced volcanic plumes that rose as high as 700 m above the crater rim. Crater incandescence was observed nightly in webcam images. No explosions were recorded. 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.

References:

¹ Smithsonian Institution / US Geological Survey – Weekly Volcanic Activity Report – June 5 – 11, 2024 – Managing Editor: Sally Sennert.

Featured image credit: TW

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