The Weekly Volcanic Activity Report: June 26 - July 2, 2024

New activity/unrest was reported for 5 volcanoes from June 26 – July 2, 2024. During the same period, ongoing activity was reported for 20 volcanoes.

New activity/unrest: Ambae, Vanuatu | Etna, Sicily (Italy) | Home Reef, Tonga Ridge | Kanlaon, Philippines | Karymsky, Eastern Kamchatka (Russia).

New activity/unrest

Ambae, Vanuatu

15.389°S, 167.835°E | Summit elev. 1496 m

On 27 June the Vanuatu Meteorology and Geohazards Department (VMGD) reported that steam-and-gas emissions from the active vents at Ambae were ongoing during the previous month based on webcam and satellite images and field observations. Seismic data also confirmed ongoing unrest. The emissions contained ash and sulfur dioxide during 29-30 June based on satellite data. According to the Wellington VAAC ash plumes rose km (8,000-11,000 ft) a.s.l. and drifted E, NE, W, and NW. Residents reported ashfall in areas downwind. The Alert Level remained at 2 (on a scale of 0-5), and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains.

Geological summary: The island of Ambae, also known as Aoba, is a massive 2,500 km3 basaltic shield that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW-trending rift zone with numerous scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and Manaro Lakua) is located at the summit within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. That large central edifice is also called Manaro Voui or Lombenben volcano. Post-caldera explosive eruptions formed the summit craters about 360 years ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast.

Etna, Sicily (Italy)

37.748°N, 14.999°E | Summit elev. 3357 m

INGV reported that eruptive activity was recorded at Etna’s Bocca Nuova Crater, Southeast Crater, and Voragine Crater during the month of June. Gas emissions at Bocca Nuova Crater were variable and sometimes high-temperature pulses were visible as incandescent flashes at night. Occasional emissions of red ash were visible but quickly dissipated. At Southeast Crater fumarolic gas emissions rose from the E part of the cone and from the 2 April pit crater on the N crater rim. Diffuse ash emissions from the E vent were visible during 6-9 June. At Voragine Crater weak Strombolian activity began during 13-14 June at a vent located at the southern inner wall of a cinder cone formed during 2019-2021 activity. Initially explosions occurred about every 10 minutes and built small hornitos. Over a period of days, the material accumulated and formed a small scoria cone; Strombolian activity at two vents began to intensify on 26 June. The new cinder cone reached about 20 m high during 27-30 June. On 29 June lava from the SE side of the cone flowed into Bocca Nuova Crater and on 1 July a lava flow effused from a vent on the NW flank.

Geological summary: Mount Etna, towering above Catania on the island of Sicily, has one of the world’s longest documented records of volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.

Home Reef, Tonga Ridge

18.992°S, 174.775°W | Summit elev. -10 m

The Tonga Geological Services reported that an eruption at Home Reef was ongoing during 26 June-2 July. Daily thermal anomalies were identified in satellite images, though the number and intensity of the anomalies were variable. Continuous steam emissions were visible during 1-2 July, indicating ongoing activity. Lava effusion continued to expand the extent of the island, increasing from 8.9 hectares on 15 June to 11.7 hectares by 30 June. The Maritime Alert Level remained at Orange (the second highest level on a four-color scale) and mariners were advised to stay 4 km away from the island, the Aviation Color Code remained at Yellow (the second lowest color on a four-color scale), and the Alert level for residents of Vava’u and Ha’apai remained at Green (the lowest color on a four-color scale).

Geological summary: Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption.

Kanlaon, Philippines

10.4096°N, 123.13°E | Summit elev. 2422 m

PHIVOLCS reported that daily diffuse gas-and-steam emissions at Kanlaon rose 100-150 m and drifted mainly NW, W, and SW during 25 June-2 July. Sulfur dioxide emissions averaged 2,774 tonnes/day (t/d) on 25 June, 3,299 t/d on 27 June, and peaked at 5,397 t/d on 28 June, the highest value recorded since instrumental gas monitoring began. Emissions averaged 3,007 t/d on 30 June and then peaked again at 5,083 t/d on 2 July, the second highest recorded value in 2024 and the third highest since monitoring began. PHIVOLCS noted that increased sulfur dioxide emissions had been recorded in 2024, averaging 1,897 t/d, though emission since the 3 June eruption were particularly elevated with a current average of 3,254 t/d. There were 1-14 daily volcanic earthquakes recorded by the seismic network; volcanic earthquake activity persisted at an average of 10 events/day since the 3 June eruption. 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 Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall.

Karymsky, Eastern Kamchatka (Russia)

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

KVERT reported that explosive activity at Karymsky that started on 20 June continued through 27 June. Daily explosions generated ash plumes that rose as high as 6 km (19,700 ft) a.s.l. and drifted 540 km SE, S, SW, and W. A thermal anomaly was identified in satellite images during 20-21 and 24-27; dense weather clouds obscured views during 22-23 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: 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.

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 24 June-1 July. Nighttime crater incandescence and very small eruptive events were recorded during 24-28 June. Weather clouds prevented visual observations on the other days. 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 26 June-2 July. Daily gray-and-white ash plumes that were sometimes dense rose 100-1,000 m above the summit and drifted W, NW, and E. 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 21-27 June. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions on 25 and 27 June generated ash plumes that rose as high as 2 km (6,600 ft) a.s.l. and drifted S and SE. Thermal anomalies was identified in satellite images during 20-22, 24, and 27 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.

Erta Ale, Ethiopia

13.601°N, 40.666°E | Summit elev. 585 m

Thermal anomalies in a 1 July satellite image of Erta Ale suggested activity at a vent in the N pit crater and a lava flow that traveled about 320 m SSW.

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 25 June-2 July. Daily explosions were recorded by the seismic network, averaging 1-7 per hour on most days, when counts were reported. The explosions generated gas-and-ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as 30 km N, NW, W, and SW. The explosions produced block avalanches that descended various drainages including the Ceniza (SSW), Seca (W), Trinidad (S), and Las Lajas (SE), and Honda (E). Weak rumbling sounds and shock waves that rattled nearby houses and buildings within a 7-km radius were reported on most days. Ashfall was reported during the first half of the week in areas downwind including La Soledad (11 km N), Parramos (18 km NNE), Yepocapa (8 km NW), El Porvenir (11 km SW), Finca Palo Verde, Sangre de Cristo (8 km WSW), Quisaché (8 km NW), Pochuta (24 km WNW), Patulul (30 km W). Ashfall was forecast for areas downwind during the second half of the week. The explosions also ejected incandescent material up to 200 m above the summit on most days and crater incandescence could often be seen during the night or early mornings. On 28 June a lahar descended the Ceniza drainage, carrying tree branches, trunks, and blocks as large as 1.5 m in diameter.

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 slow lava effusion in Great Sitkin’s summit crater was last confirmed in a 26 June radar image; effusion likely continued during 27 June-2 July. Seismicity was low with few daily small earthquakes recorded during 28 June-1 July. Weather clouds obscured satellite and webcam views during most of the week; slightly elevated surface temperatures were detected in satellite images during 30 June-2 July, indicating continuing effusion. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale).

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

Ibu, Halmahera

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

PVMBG reported that activity at Ibu continued during 26 June-2 July. Daily white-and-gray or white, gray, and black ash plumes rose as high as 5 km above the summit and drifted in multiple directions, though notably on 28 June ash plumes rose as high as 7 km above the summit. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5 km away from the N crater wall opening.

Geological summary: The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.

Lateiki, Tonga Ridge

19.18°S, 174.87°W | Summit elev. 43 m

Satellite data showed an area of yellowish-green discolored water in the vicinity of the submarine Lateiki volcano on 25 and 30 June. The area of discolored water on 30 June was narrow and drifted about 7 km ENE before dissipating.

Geological summary: Lateiki, previously known as Metis Shoal, is a submarine volcano midway between the islands of Kao and Late that has produced a series of ephemeral islands since the first confirmed activity in the mid-19th century. An island, perhaps not in eruption, was reported in 1781 and subsequently eroded away. During periods of inactivity following 20th-century eruptions, waves have been observed to break on rocky reefs or sandy banks with depths of 10 m or less. Dacitic tuff cones formed during the eruptions in 1967 and 1979 were soon eroded beneath the ocean surface. An eruption in 1995 produced an island with a diameter of 280 m and a height of 43 m following growth of a lava dome above the surface.

Lewotobi, Flores Island

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

PVMBG reported that eruptive activity at Lewotobi’s Laki-laki volcano continued during 26 June-2 July. Multiple daily gray or white-and-gray ash plumes that were sometimes dense rose 50-1,000 m above the summit and drifted SW, W, and NW. An eruptive event that began at 1421 on 29 June lasted 10 minutes and 14 seconds based on the seismic data and produced a dense ash plume that rose around 900 m above the summit and drifted SW and W. According to a news article the Frans Seda Maumere Airport (60 km WSW) canceled flights from Kupang to Maumere on 2 July, though cancellations may have also occurred during the previous two days. Ashfall continued to impact residents in areas to the S and SW including Hokeng Jaya (4 km NW), Klatanlo (5 km NW), Persiapan Padang Pasir, Boru (8 km WNW), Pululera (6 km NW), Goloriang, Wotupudor, and Kumaebang. The Alert Level remained at 3 (the second highest level on a scale of 1-4) and the public was warned to stay outside of the exclusion zone, defined as a 3-km radius around both Laki-laki and Perempuan craters, 4 km to the NNW and SSE of Laki-laki.

Geological summary: The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the “husband and wife”). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan.

Lewotolok, Lembata Island

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

PVMBG reported that the eruption at Lewotolok continued during 26 June-2 July. White steam-and-gas emissions rose as high as 400 m above the summit and drifted N, NW, and W during 26-29 July. Emissions were not visible on 30 June. A white-and-gray ash plume rose as high as 300 m above the summit and drifted W and NW during 1-2 July. Summit incandescence was visible in webcam images during the week. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the vent and 2.5 km away from the vent on the S, SE, and W 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 26 June-2 July. White gas-and-steam plumes rose as high as 300 m above the summit and drifted in multiple directions on 26 and 29 June and 2 July. Gray ash plumes rose 500 m above the summit and drifted SW on 28 June based on a Darwin VAAC report. Emissions were not observed on the other days. PVMBG noted that activity had generally declined during the previous two weeks. Seismic signals indicating eruptive events were at low levels, deformation data indicated deflation, and sulfur dioxide emissions were at low levels. At 1500 on 1 July the Alert Level was lowered to 2 (on a scale of 1-4), and the public was warned to stay 3 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 21-27 June. Seismicity had decreased compared to the previous week. The SW lava dome produced 86 lava avalanches that traveled as far as 2 km down the upper part of the Bebeng drainage on the SW flank. Morphological changes to the SW lava dome were due to continuing effusion and collapses of material. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit, based on location.

Geological summary: Merapi, one of Indonesia’s most active volcanoes, lies in one of the world’s most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities.

Popocatepetl, Mexico

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

CENAPRED reported that eruptive activity continued at Popocatépetl during 25 June-2 July. The seismic network recorded 10-51 long-period events per day that were accompanied by steam-and-gas emissions; the emissions sometimes contained minor amounts of ash. Weather clouds sometimes prevented visual observations. The seismic network also recorded daily periods of tremor as short as 14 minutes to as long as five and a half hours. A M 1.5 volcano-tectonic earthquake was recorded during 28-29 June. According to the Washington VAAC ash plumes visible in webcam and satellite images rose to 5.8-6.4 km (19,000-21,000 ft) a.s.l. (or as high as 1 km above the crater rim) and drifted NW and SW during 29-30 June. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater.

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 high-level eruptive activity continued at Santa Maria’s Santiaguito lava-dome complex during 25 June-2 July with lava extrusion, block collapses, and avalanches at the Caliente dome complex. The continuous effusion of blocky lava produced block avalanches on the dome’s flanks and occasional short pyroclastic flows that descended multiple flanks, creating promontories of unstable material. Incandescence from avalanches of material at the dome as well as explosions was visible during most nights and early mornings, and occasional incandescence was also present along the upper parts of the lava flow on the WSW flank. Lava extrusion fed the upper parts of the lava flow, and block avalanches occasionally traveled over the lava flow. Daily explosions (a few per hour on most days) generated gas-and-ash plumes that rose 700-900 m above the summit and drifted mainly NW, W, and SW. Ashfall was reported in San Marcos (8 km SW) and Loma Linda Palajunoj (7 km SW) during 26-27 June. Rain caused steam to rise from the lava flows in the Zanjón Seco (SW) and San Isidro (W) drainages during 29-30 June. On 1 July a lahar descended the Cabello de Ángel river, a tributary of the Nimá I, on the SE flank, carrying tree trunks, branches, and volcanic blocks up to 1 m in diameter. Weather conditions sometimes prevented visual observations.

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.

Semeru, Eastern Java

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

PVMBG reported that eruptive activity continued at Semeru during 23 June-2 July. Seismicity remained at high levels. Daily white-and-gray ash plumes that were sometimes dense rose 300-1,000 m above the summit and drifted mainly W and SW and occasionally S and SE. Daily eruptive events, sometimes several per day, were recorded by the seismic network, though plumes were not always visually confirmed. Incandescent lava avalanches occasionally descended the Kobokan drainage on the SE flank as far as 1.5 km during 23-30 June. 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 “300 years of RAS” dome and the older lava dome at Sheveluch were identified in satellite images during 21-27 June. Both domes continued to grow. 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 24 June-1 July and produced volcanic plumes that rose as high as 500 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.

Taal, Luzon (Philippines)

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

PHIVOLCS reported that daily steam-and-gas emissions were visible in webcam images rising as high as 1.8 km above the rim of Taal’s Main Crater and drifting SW, W, and NW during 25 June-2 July. Sulfur dioxide emissions averaged 5,100 tonnes per day (t/d) on 25 June, 6,571 t/d on 28 June, and 2,116 t/d on 1 July; the emissions were high, though below the 2024 average of 7,895 t/d. Phreatic events at 1431 and 1439 on 29 June each lasted one minute based on seismic and infrasound data, and generated steam-laden plumes that rose 800 m above Main Crater and drifted SW. 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.

Villarrica, Central Chile

39.42°S, 71.93°W | Summit elev. 2847 m

SERNAGEOMIN reported that at 0428 on 25 June an explosion at Villarrica ejected incandescent material onto the upper flanks. According to POVI a series of phreatomagmatic pulses on 29 June produced an ash plume that drifted E and deposited ash on the E flank. The Volcanic Alert Level remained at Yellow (the second lowest level on a four-level scale) and the public was warned to stay 500 m away from the active crater.

Geological summary: The glacier-covered Villarrica stratovolcano, in the northern Lakes District of central Chile, is ~15 km south of the city of Pucon. A 2-km-wide caldera that formed about 3,500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesite cone at the NW margin of a 6-km-wide Pleistocene caldera. More than 30 scoria cones and fissure vents are present on the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano were produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Eruptions documented since 1558 CE have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged towns on its flanks.

Yasur, Vanuatu

19.532°S, 169.447°E | Summit elev. 361 m

On 27 June the Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a level of “major unrest,” as defined by the Alert Level 2 status (on a scale of 0-5). Recent visual observations, webcam mages, and photos taken in the field indicated that explosions continued, producing emissions of gas, steam, and/or ash. Seismic data indicated that some of the explosions were strong. Gas emissions and thermal anomalies were identified in satellite images. The report warned that some of the explosions may eject material that falls in and around the crater. The public was reminded to not enter the restricted area within 600 m around the boundaries of the Permanent Exclusion Zone, defined by Danger Zone A on the hazard map.

Geological summary: Yasur has exhibited essentially continuous Strombolian and Vulcanian activity at least since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island in Vanuatu, this pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide open feature associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century.

References:

¹ Smithsonian Institution / US Geological Survey – Weekly Volcanic Activity Report – June 26 – July 2, 2024 -Managing Editor: Sally Sennert.

Featured image credit: TW

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