The Weekly Volcanic Activity Report: March 13 - 19, 2019

The Weekly Volcanic Activity Report: March 13 - 19, 2019

New activity/unrest was reported for 7 volcanoes from March 13 to 19, 2019. During the same period, ongoing activity was reported for 12 volcanoes.

New activity/unrest: Barren Island, Andaman Islands (India) | Bezymianny, Central Kamchatka (Russia) | Karymsky, Eastern Kamchatka (Russia) | Kirishimayama, Kyushu (Japan) | Mayon, Luzon (Philippines) | Tengger Caldera, Eastern Java (Indonesia) | Villarrica, Chile.

Ongoing activity: Agung, Bali (Indonesia) | Aira, Kyushu (Japan) | Dukono, Halmahera (Indonesia) | Ebeko, Paramushir Island (Russia) | Kerinci, Indonesia | Krakatau, Indonesia | Merapi, Central Java (Indonesia) | Poas, Costa Rica | Popocatepetl, Mexico | Reventador, Ecuador | Sheveluch, Central Kamchatka (Russia) | Suwanosejima, Ryukyu Islands (Japan).

New activity/unrest

Barren Island, Andaman Islands (India)

12.278°N, 93.858°E, Summit elev. 354 m

Based on analysis of satellite imagery and wind data, the Darwin VAAC reported that on 14 and 16 March ash plumes from Barren Island rose to altitudes of 0.9 km (3,000 ft) and 1.2 km (4,000 ft) a.s.l., respectively, and drifted W and SW.

Geological summary: Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S volcanic arc extending between Sumatra and Burma (Myanmar). It is the emergent summit of a volcano that rises from a depth of about 2250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast.

Bezymianny, Central Kamchatka (Russia)

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

KVERT reported that a thermal anomaly over Bezymianny was identified in satellite images during 12-15 March, and intense gas-end-steam emissions continued to rise from the crater. Hot avalanches originating from the top of the lava dome were visible in webcam images at night.

Late on 15 March KVERT reported that activity continued to intensify noting that the number of hot avalanches increased and ash plumes from the avalanches drifted about 100 km SE. The temperature of the thermal anomaly also increased. The Aviation Color Code was raised to Red (the highest level on a four-color scale). Seismic data suggested that a powerful explosive eruption began at 0511 on 16 March. At 0530 webcam images recorded explosions generating ash plumes that rose as high as 15 km (49,200 ft) a.s.l. and drifted 10 km E. Thirty minutes later satellite images indicated continuing ash emissions rising to 15 km a.s.l. Ashfall was reported in Ust-Kamchatsk Village (120 km ENE) during 0650-0730. An ash plume, 79 x 65 km in dimension, was also identified drifting ENE.

Strong explosions continued to produce ash plumes on 16 March, although they were lower-altitude (5-6 km (16,400-19,700 ft) a.s.l.) and had a higher concentration of ash. The plumes drifted E. By 0930 ash plumes were rising to altitudes of 4-4.5 (13,100-14,800 ft) a.s.l.; ash plumes drifted 100 km E. A large ash plume, 120 x 130 km in dimension, continued to drift E at an altitude of 15 km. The Aviation Color Code was lowered to Orange (the second highest level on a four-color scale). By 1307 on 16 March satellite images showed ash plumes drifting 650 km E. The report noted that ashfall was likely occurring in Nikolskoye (370 km ESE) on Bering Island.

Geological summary: Prior to its noted 1955-56 eruption, Bezymianny had been considered extinct. The modern volcano, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago over a late-Pleistocene lava-dome complex and an ancestral edifice built about 11,000-7000 years ago. Three periods of intensified activity have occurred during the past 3000 years. The latest period, which was preceded by a 1000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large horseshoe-shaped 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.

Karymsky, Eastern Kamchatka (Russia)

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

KVERT reported that during 8-12 March explosions at Karymsky generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted about 100 km E. A thermal anomaly was visible on 10 and 12 March. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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.

Kirishimayama, Kyushu (Japan)

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

The number of volcanic earthquakes below Shinmoedake (Shinmoe peak), a stratovolcano of the Kirishimayama volcano group, increased on 25 February prompting JMA to raise the Alert Level to 2 (on a scale of 1-5). The number of daily volcanic earthquakes decreased during 3-4 March, and each day through 18 March only a few were recorded.

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.

Mayon, Luzon (Philippines)

13.257°N, 123.685°E, Summit elev. 2462 m

PHIVOLCS reported that during 13-19 March white steam plumes periodically emitted from Mayon drifted mainly W and SW, and crater incandescence was visible nightly. Three phreatic events, recorded at 1510, 1518, and 1534 on 12 March, generated light-brown-to-grayish ash plumes that rose 500-1,000 m above the crater rim and drifted SW. Six phreatic events on 13 March, recorded at 0906, 0939, 0946, 0955, 1000, and 1059, produced ash plumes that rose 200-700 m and drifted W. A phreatic event at 1855 on 14 March generated an ash plume that rose 500 m and drifted SW. The Alert Level remained at 2 (on a 0-5 scale) and PHIVOLCS reminded residents to stay away from the 6-km-radius Permanent Danger Zone and the 7-km Extended Danger Zone on the SSW and ENE flanks.

Geological summary: Beautifully symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the Philippines' most active volcano. The structurally simple edifice has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions date back to 1616 and range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often devastated populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Tengger Caldera, Eastern Java (Indonesia)

7.942°S, 112.95°E, Summit elev. 2329 m

PVMBG reported that during 1 January-17 March plumes rising from Tengger Caldera’s Bromo cone were generally white to gray in color, had variable densities, and rose no higher than 700 m above the crater rim. Tremor signals increased on 10 March and were accompanied by changes in the color and height of the emissions. On 16 March a dense gray ash plume rose 1.5 km and drifted E, causing ashfall in areas both inside and outside the caldera. Two seismic signals indicating explosions were recorded around 1547 on 17 March. Periods of continuous ash emissions were observed during 17-18 March, with ash plumes rising as high as 1.2 km above the crater rim and drifting NE, N, NW, and W. At 1020 on 19 March a black ash plume rose 1.5 km and drifted E and NE. The Alert Level remained at 2 (on a scale of 1-4).

Geological summary: The 16-km-wide Tengger caldera is located at the northern end of a volcanic massif extending from Semeru volcano. The massive volcanic complex dates back to about 820,000 years ago and consists of five overlapping stratovolcanoes, each truncated by a caldera. Lava domes, pyroclastic cones, and a maar occupy the flanks of the massif. The Ngadisari caldera at the NE end of the complex formed about 150,000 years ago and is now drained through the Sapikerep valley. The most recent of the calderas is the 9 x 10 km wide Sandsea caldera at the SW end of the complex, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most active and most frequently visited volcanoes.

Villarrica, Chile

39.42°S, 71.93°W, Summit elev. 2847 m

POVI reported that on 17 March sporadic Strombolian explosions at Villarrica ejected incandescent material about 25 m above the summit crater rim.

Geological summary: Glacier-clad Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A 2-km-wide caldera that formed about 3500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesitic cone at the NW margin of the Pleistocene caldera. More than 30 scoria cones and fissure vents dot 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. Historical eruptions, documented since 1558, 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.

Ongoing activity

Agung, Bali (Indonesia)

8.343°S, 115.508°E, Summit elev. 2997 m

PVMBG reported that at 1827 on 15 March an explosive event at Agung was recorded for one minute and 23 seconds and produced a dense gray ash plume that rose about 1 km above the crater rim and drifted NNW. Minor ashfall was reported in the villages of Kubu (6 km N), Tianyar (14 km NNW), Ban, Kadundung, and Sukadana. At 0803 on 17 March an event was recorded for 39 seconds and produced a dense gray ash plume that rose about 500 m above the crater rim and drifted E. A second event began at 1030 and lasted about one minute and 16 seconds; a dense gray ash plume rose about 600 m and drifted E. At 0736 on 18 March an ash plume rose 1 km and drifted W and NW. Thermal satellite images continue to indicate hot areas in the crater on the previously-erupted lava surface especially near the flow margins. The Alert Level remained at 3 (on a scale of 1-4) with the exclusion zone set at a 4-km radius.

Geological summary: Symmetrical Agung stratovolcano, Bali's highest and most sacred mountain, towers over the eastern end of the island. The volcano, whose name means "Paramount," rises above the SE caldera rim of neighboring Batur volcano, and the northern and southern flanks extend to the coast. The summit area extends 1.5 km E-W, with the high point on the W and a steep-walled 800-m-wide crater on the E. The Pawon cone is located low on the SE flank. Only a few eruptions dating back to the early 19th century have been recorded in historical time. The 1963-64 eruption, one of the largest in the 20th century, produced voluminous ashfall along with devastating pyroclastic flows and lahars that caused extensive damage and many fatalities.

Aira, Kyushu (Japan)

31.593°N, 130.657°E, Summit elev. 1117 m

JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible during 11-18 March. There were nine events and four explosions detected during 11-15 March ejecting material as far as 1.3 km. One of the events, recorded at 2323 on 14 March generated an ash plume that rose 3.5 km above the crater rim and ejected material as far as 1.1 km. During 16-18 March there were eight events and two explosions. Ash plumes rose as high as 2.7 km. The Alert Level remained at 3 (on a 5-level scale).

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 Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.

Dukono, Halmahera (Indonesia)

1.693°N, 127.894°E, Summit elev. 1229 m

Based on satellite images, wind model data, and PVMBG observations, the Darwin VAAC reported that during 13-18 March ash plumes from Dukono rose to altitudes of 1.5-2.4 km (5,000-8,000 ft) a.s.l. and drifted S, SE, and SSE. The Alert Level remained at 2 (on a scale of 1-4), and visitors were warned to remain outside of the 2-km exclusion zone.

Geological summary: Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the north-flank cone of Gunung Mamuya. 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

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 8-10 March that sent ash plumes to 4 km (13,100 ft) a.s.l. Satellite images showed the ash plume drifting about 30 km ENE. Ash fell in Severo-Kurilsk during 9-10 March. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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.

Kerinci, Indonesia

1.697°S, 101.264°E, Summit elev. 3800 m

The Darwin VAAC reported that on 13 March an ash plume from Kerinci rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted S based on information from PVMBG. On 15 March an ash plume identified in satellite images rose to an altitude of 4.3 (14,000 ft) a.s.l. and drifted W. The Alert Level remained at 2 (on a scale of 1-4), and tourists were warned to remain outside of the 3-km exclusion zone.

Geological summary: Gunung Kerinci in central Sumatra forms Indonesia's highest volcano and is one of the most active in Sumatra. It is capped by an unvegetated young summit cone that was constructed NE of an older crater remnant. There is a deep 600-m-wide summit crater often partially filled by a small crater lake that lies on the NE crater floor, opposite the SW-rim summit. The massive 13 x 25 km wide volcano towers 2400-3300 m above surrounding plains and is elongated in a N-S direction. Frequently active, Kerinci has been the source of numerous moderate explosive eruptions since its first recorded eruption in 1838.

Krakatau, Indonesia

6.102°S, 105.423°E, Summit elev. 813 m

PVMBG reported that there were four explosive events at Anak Krakatau on 14 March, recorded at 0816, 1711, 1716, and 2126, producing white plumes that drifted S and SW. An event at 0953 on 16 March produced a white plume that rose 1 km and drifted N. White plumes from events at 0605 and 0905 on 18 March generated white plumes that rose 500 m and drifted N. The Alert Level remained at 3 (on a scale of 1-4), and residents were warned to remain outside of the 5-km radius hazard zone from the crater.

Geological summary: The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of this ancestral volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption, the 2nd largest in Indonesia during historical time, caused more than 36,000 fatalities, most as a result of devastating tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927.

Merapi, Central Java (Indonesia)

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

PVMBG reported that the slow extrusion of a lava dome in Merapi’s summit crater continued during 11-17 March. The volume of the lava dome had not changed since the last measurement of 470,000 cubic meters estimated on 5 March. There were no apparent morphological changes; most of the extruded lava fell into the upper parts of the Gendol River drainage on the SE flank. Block-and-ash flows traveled as far as 1,500 m down the Gendol drainage on 12, 15, and 17 March. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain outside of the 3-km exclusion zone.

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 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive 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 during historical time.

Poas, Costa Rica

10.2°N, 84.233°W, Summit elev. 2708 m

OVSICORI-UNA reported that on 18 March an event at Poás produced a plume with minor ash content that rose 200 m above the crater rim.

Geological summary: The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica's most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2708-m-high complex stratovolcano extends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water.

Popocatepetl, Mexico

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

CENAPRED reported that each day during 13-19 March there were 43-175 steam-and-gas emissions from Popocatépetl, some of which contained ash. Crater incandescence was visible most nights. A short period of Strombolian activity commenced at 0500 on 13 March and lasted for 15 minutes, ejecting incandescent fragments onto the E and SE flanks. An explosion at 0510 generated an ash plume that rose 1.5 km above the crater rim and ejected incandescent material 1.7 km away and onto the ESE flank. An ash plume from an explosion at 0730 rose 3.5 km and drifted NE. An explosion at 1430 on 14 March generated a dense ash plume that rose 5 km and drifted NNE. During an overflight of the crater on 15 March observers noted that lava dome #82 was gone, and that the inner crater was 300 m wide and 130 m deep. Explosions at 0255 and 0930 on 16 March produced ash plumes that rose 2-2.5 km and drifted NNE. Explosions were detected at 2206, 2321, and 2325. Gas, steam, and ash plumes from an event at 2138 on 18 March rose 4 km and drifted E. Incandescent fragments were ejected 2.5 km onto the flanks and set fire to some grasslands. The Alert Level remained at Yellow, Phase Two (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.

Reventador, Ecuador

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

IG reported that during 13-19 March periodic seismic data from Reventador’s network indicated a high level of seismic activity, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Steam, gas, and ash plumes sometimes rose higher than 1 km above the crater rim and drifted W and NW. Incandescent blocks were observed rolling 500-700 m down the flanks on a few of the days. Inclement weather sometimes prevented visual observations.

Geological summary: 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 Volcán El Reventador stratovolcano rises to 3562 m above the jungles of the western Amazon basin. A 4-km-wide caldera widely breached to the east was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1300 m above the caldera floor to a height comparable to the caldera rim. It has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. The largest historical 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.

Sheveluch, Central Kamchatka (Russia)

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

KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 8-15 March. Explosions on 9 March generated ash plumes that rose to 11 km (36,100 ft) a.s.l. and drifted 375 km NNW, causing KVERT to temporarily raise the Aviation Color Code to Red. Forceful gas-and-steam emissions containing variable amounts of ash rose to 3.5-4 km (11,500-13,100 ft) a.s.l. and drifted E during 10-11 March. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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 crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 8-15 March. Small events were occasionally recorded, generating plumes that rose as high as 400 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).

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 of the volcano 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.

Source: GVP

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