Active volcanoes in the world: March 26 - April 1, 2014

Active volcanoes in the world: March 26 - April 1, 2014

New activity/unrest was observed at 9 volcanoes from March 26 - April 1, 2014. Ongoing activity was reported for 12 volcanoes.

New activity/unrest: Copahue, Central Chile-Argentina border  | Karkar, Papua New Guinea  | Krakatau, Indonesia  | Merapi, Central Java (Indonesia)  | Poás, Costa Rica  | Reventador, Ecuador  | Shishaldin, Fox Islands (USA)  | Slamet, Central Java (Indonesia)  | Ubinas, Peru

Ongoing activity: Aira, Kyushu (Japan)  | Batu Tara, Komba Island (Indonesia)  | Chirinkotan, Kuril Islands (Russia)  | Chirpoi, Kuril Islands (Russia)  | Dukono, Halmahera (Indonesia)  | Etna, Sicily (Italy)  | Grímsvötn, Iceland  | Karymsky, Eastern Kamchatka (Russia)  | Kilauea, Hawaiian Islands (USA)  | Shiveluch, Central Kamchatka (Russia)  | Sinabung, Indonesia  | Tungurahua, Ecuador

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 23:00 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail.

New activity/unrest

Copahue, Central Chile-Argentina border
37.856°S, 71.183°W  | Summit elev. 2953 m

OVDAS-SERNAGEOMIN reported that cameras installed around Copahue recorded white gas plumes rising 100-600 m above the crater during 25-29 March; clouds prevented observations on 30 March. Sulfur dioxide measurements in tons per day were 270 on 26 March, 1,400 on 27 March, 2,000 on 28 March, 1,400 on 29 March, and 920 on 30 March. The Alert Level remained at Orange.

Geologic summary: Volcán Copahue is an elongated composite cone constructed along the Chile-Argentina border within the 6.5 x 8.5 km wide Trapa-Trapa caldera that formed between 0.6 and 0.4 million years ago near the NW margin of the 20 x 15 km Pliocene Caviahue (Del Agrio) caldera. The eastern summit crater, part of a 2-km-long, ENE-WSW line of nine craters, contains a briny, acidic 300-m-wide crater lake (also referred to as El Agrio or Del Agrio) and displays intense fumarolic activity. Acidic hot springs occur below the eastern outlet of the crater lake, contributing to the acidity of the Río Agrio, and another geothermal zone is located within Caviahue caldera about 7 km NE of the summit. Infrequent mild-to-moderate explosive eruptions have been recorded at Copahue since the 18th century. Twentieth-century eruptions from the crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments.

Karkar, Papua New Guinea 
4.649°S, 145.964°E  | Summit elev. 1839 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 26-27 March ash plumes from Karkar rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted almost 50 km ENE and NW.

Geologic summary: Karkar is a 19 x 25 km wide, forest-covered island that is truncated by two nested summit calderas. The 5.5-km-wide outer caldera was formed during one or more eruptions, the last of which occurred 9000 years ago. The eccentric 3.2-km-wide inner caldera was formed sometime between 1500 and 800 years ago. Parasitic cones are present on the northern and southern flanks of basaltic-to-andesitic Karkar volcano; a linear array of small cones extends from the northern rim of the outer caldera nearly to the coast. Most historical eruptions, which date back to 1643, have originated from Bagiai cone, a pyroclastic cone constructed within the steep-walled, 300-m-deep inner caldera. The floor of the caldera is covered by young, mostly unvegetated andesitic lava flows.

Krakatau, Indonesia
6.102°S, 105.423°E  | Summit elev. 813 m

Based on a pilot observation, the Darwin VAAC reported that on 31 March an ash plume from Anak Krakatau rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted N. Ash was not identified in satellite images.

Geologic 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 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 volcanoes, and left only a remnant of Rakata volcano. 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)
7.542°S, 110.442°E  | Summit elev. 2968 m

PVMBG reported explosions from Merapi on 9 March. An explosion detected at 0654 was followed by a plume observed on CCTV from Pasarbubar that drifted W. Two Explosions were also recorded at 0655. At 0708 a volcanic earthquake occurred and CCTV in Market Bubar recorded brown plumes that rose 1.5 km above the crater. At 0730 ash fell in the villages of Umbulharjo (30 km S), Kepuharjo, Sidorejo (27 km NNE), and Balerante (6 km SSE). During 14-20 March dense gas plumes rose 600 m. Seismicity was at normal levels. The Alert Level remained at 1 (on a scale of 1-4).

Based on analysis of satellite images, the Darwin VAAC reported that on 27 March an ash plume rose to an altitude of 9.8 km (32,000 ft) a.s.l. and drifted SE. The VAAC noted that an eruption occurred around 0630, confirmed by a news article. Ash had dissipated the next day. Another news article noted that the increased activity lasted only four minutes, from 0112 to 0116, and that ashfall occurred on the S and SE flanks.

Geologic 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. Merapi is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi volcano beginning 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 volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory.

Poás, Costa Rica
10.2°N, 84.233°W  | Summit elev. 2708 m

OVSICORI-UNA reported that a strong phreatic eruption from Poás was recorded at 1532 on 30 March. The explosion ejected water, steam, gases, sediment, and fragments of altered rock 150 m above the crater lake’s surface. The report noted several small phreatic eruptions that ejected material less than 50 m high, as well as large gas bubbles and vapor in the middle of the lake, during February and March.

Geologic 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. Poás eruptions often include geyser-like ejections of crater-lake water.

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

IG reported that activity at Reventador increased on 25 March. At 1830 an explosion was followed by a pyroclastic flow that traveled 500 m down the flanks. Strombolian activity produced gas-and-ash plumes that rose 1.5 km above the crater. During 26-29 March continuous tremor was interspersed with explosions and long-period earthquakes. Although cloud cover often prevented crater views, video cameras showed a lava flow traveling down the S flank and incandescent material erupting from the crater. Emissions with small amounts of ash rose 1 km on 28 March. Ashfall was reported in Hosteria El Reventador and camp San Rafael on the flanks. A load roar reported at 0300 on 31 March was followed by observations of incandescent material traveling 1 km down the S flank. Cloud cover prevented visual observations the next day.

Geologic 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. Reventador 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 at Reventador 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.

Shishaldin, Fox Islands (USA)
54.756°N, 163.97°W  | Summit elev. 2857 m

AVO reported that ground-coupled air waves from small explosions at Shishaldin's summit area were detected in seismic data during 25-27 March, although the energy and rate of occurrence both declined over that time. Elevated surface temperatures were identified in satellite images on 27 March. Based on the elevated surface temperatures and explosions persistent since 18 March AVO raised the Aviation Color Code to Orange and the Volcano Alert Level to Watch on 28 March. Analysis of the data showed that the temperatures were consistent with an eruption of lava within the summit crater. Web-camera images, satellite data, and pilot observations during the previous week indicated only minor steam emissions from the summit crater; there had been no evidence of ash emissions. Explosions were detected during 29-30 March; elevated surface temperatures were identified during 30-31 March.

Geologic summary: The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, Shishaldin is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. Shishaldin contains over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.

Slamet, Central Java (Indonesia)
7.242°S, 109.208°E  | Summit elev. 3428 m

PVMBG reported that during 8-14 March dense white plumes rose as high as 1.2 km above Slamet, and ash plumes rose 800-1,000 m and drifted E. Incandescence from the crater was observed at 2148 during an eruption on 14 March. Brownish-white plumes rose 2 km on 15 March and ash plumes rose 1.2 km and again drifted E. During 22-28 March white-to-gray plumes rose 1.3 km. Dense gray ash plumes rose 2 km and drifted W. White plumes were observed on 29 March. Various seismic signals including shallow volcanic earthquakes, harmonic tremor, and volcanic earthquakes fluctuated during 8-28 March. Carbon dioxide emissions significantly increased during 17-20 March. PVMBG noted that activity, based on visual and instrument monitoring, continued to fluctuate; on 29 March the Alert Level remained at 2 (on a scale of 1-4). Residents and tourists were warned not approach the crater within a radius of 2 km.

Geologic summary: Slamet, Java's second highest volcano at 3428 m and one of its most active, has a cluster of about three dozen cinder cones on its lower SE-NE flanks and a single cinder cone on the western flank. Slamet is composed of two overlapping edifices, an older basaltic-andesite to andesitic volcano on the west and a younger basaltic to basaltic-andesite one on the east. Gunung Malang II cinder cone on the upper eastern flank on the younger edifice fed a lava flow that extends 6 km to the east. Four craters occur at the summit of Gunung Slamet, with activity migrating to the SW over time. Historical eruptions, recorded since the 18th century, have originated from a 150-m-deep, 450-m-wide, steep-walled crater at the western part of the summit and have consisted of explosive eruptions generally lasting a few days to a few weeks.

Ubinas, Peru
16.355°S, 70.903°W  | Summit elev. 5672 m

IGP's Observatorio Volcanologico de Arequipa (IGP-OVA) reported that volcanologists visiting Ubinas on 19 March observed that lava had continued erupt, covering the 120-m-wide crater floor. Seismic signals detected during 20-21 and 23 March indicating increased lava emissions. Gas-and-ash plumes rose as high as 1.3 km above the crater almost daily during 10-25 March; ashfall was reported on 25 March in nearby villages and noises from the volcano were audible in areas as far as 6 km SE.

INGEMMET reported that on 26 March gas-and-ash emissions rose 1.2-1.7 km and drifted NE, E, and SW. Small amounts of fine ash fell within 4 km of the crater. Ash emissions on 27 March caused ashfall in Ubinas (6.5 km SSE), Querapi (4 km S), and Tonohaya (7 km SSE). Rockslides traveled down the SE flank. On 28 March residents of Ubinas reported noises from the volcano. Seismicity increased the next day and was characterized by long-period earthquakes and harmonic tremor. On 30 March gas-and-steam plumes rose as high as 1.2 km. A news article stated that residents of Querapi had started to evacuate. A low-energy explosion occurred at 0743 on 31 March and produced an ash plume that rose 1.2 km. More low-energy explosions followed: at 1119, 1306, 1518, and 1616. The explosions produced ash plumes that rose 1-1.8 km. Ashfall was reported in Ubinas and Querapi.

Geologic summary: A small, 1.4-km-wide caldera cuts the top of Ubinas, Peru's most active volcano, giving it a truncated appearance. Ubinas is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Perú. The growth and destruction of Ubinas I volcano was followed by construction of Ubinas II volcano beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank of Ubinas about 3700 years ago extend 10 km from the volcano. Widespread plinian pumice-fall deposits from Ubinas include one of Holocene age about 1000 years ago. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.

Ongoing activity

Aira, Kyushu (Japan)
31.593°N, 130.657°E  | Summit elev. 1117 m

JMA reported that 20 explosions from Showa Crater at Aira Caldera’s Sakurajima volcano during 24-28 March ejected tephra as far as 1,300 m. Incandescence from the crater was detected at night on 25 March. The Alert Level remained at 3 (on a scale of 1-5). The Tokyo VAAC reported an explosion on 26 March. During 27-29 March plumes rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted SE, N, and NW.

Geologic 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.

Batu Tara, Komba Island (Indonesia)
7.792°S, 123.579°E  | Summit elev. 748 m

Based on analyses of satellite imagery and wind data, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that on 26 March an ash plume from Batu Tara drifted almost 30 km W.

Geologic summary: The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lembata (fomerly Lomblen) Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy's Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The first historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow.

Chirinkotan, Kuril Islands (Russia)
48.98°N, 153.48°E  | Summit elev. 724 m

SVERT reported that satellite images of Chirinkotan showed diffuse gas-and-steam emissions on 24 March and steam-and-gas plumes drifting 80-170 km SE during 26-27 March. Cloud cover obscured views on the other days during 25-31 March. The Aviation Color Code remained at Yellow.

Geologic summary: The small, mostly unvegetated 3-km-wide island of Chirinkotan occupies the far end of an E-W-trending volcanic chain that extends nearly 50 km west of the central part of the main Kuril Islands arc. Chirinkotan is the emergent summit of a volcano that rises 3000 m from the floor of the Kuril Basin. A small 1-km-wide caldera about 300-400 m deep is open to the SE. Lava flows from a cone within the breached crater reached the north shore of the island. Historical eruptions have been recorded at Chirinkotan since the 18th century. Fresh lava flows also descended the SE flank of Chirinkotan during an eruption in the 1880s that was observed by the English fur trader Captain Snow.

Chirpoi, Kuril Islands (Russia)
46.525°N, 150.875°E  | Summit elev. 742 m

SVERT reported that on 27 March satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly and a steam-and-gas plume drifting more than 50 km SE. A weak thermal anomaly was detected on 28 March. Cloud cover obscured views on the other days during 24-31 March. The Aviation Color Code remained at Yellow.

Geologic summary: Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. Two volcanoes on Chirpoi Island have been historically active. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.

Dukono, Halmahera (Indonesia)
1.68°N, 127.88°E  | Summit elev. 1335 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 27-28 March ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 65-150 km W and NW.

Geologic 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. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Etna, Sicily (Italy)
37.734°N, 15.004°E  | Summit elev. 3330 m

INGV reported that Strombolian activity from Etna's New Southeast Crater (NSEC) cone ceased during the night of 26-27 March, after 64 days of persistent activity. Lava emissions from the lower side of the NSEC significantly decreased; on the evening of 28 March a small lava flow continued to advance but had stopped and was cooling the next day.

Geologic summary: Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical 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 horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater (the latter formed in 1978). 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.

Grímsvötn, Iceland
64.42°N, 17.33°W  | Summit elev. 1725 m

According to the Icelandic Meteorological Office, a small glacial outburst flood (jokulhlaup) from Grímsvötn's subglacial lake was occurring on 27 March, increasing the water level in the Gígjukvísl River; it was expected to peak by the end of the week and remain small. Electrical conductivity measurements indicated a considerable increase of a geothermal contribution to the river water. Seismic tremor had increased due to the flood and not volcanic activity. The report warned that hydrogen sulfide released from the floodwater as it drains is particularly potent at the river outlet at the ice margin, where concentrations may reach poisonous levels.

Geologic summary: Grímsvötn, Iceland's most frequently active volcano in historical time, lies largely beneath the vast Vatnajökull icecap. The caldera lake is covered by a 200-m-thick ice shelf, and only the southern rim of the 6 x 8 km caldera is exposed. The geothermal area in the caldera causes frequent jökulhlaups (glacier outburst floods) when melting raises the water level high enough to lift its ice dam. Long NE-SW-trending fissure systems extend from the central volcano. The most prominent of these is the noted Laki (Skaftar) fissure, which extends to the SW and produced the world's largest known historical lava flow during an eruption in 1783. The 15-cu-km basaltic Laki lavas were erupted over a 7-month period from a 27-km-long fissure system. Extensive crop damage and livestock losses caused a severe famine that resulted in the loss of one-fifth of the population of Iceland.

Karymsky, Eastern Kamchatka (Russia)
54.05°N, 159.45°E  | Summit elev. 1536 m

KVERT reported that Vulcanian and Strombolian activity at Karymsky continued during 21-28 March. Satellite images detected a bright thermal anomaly on the volcano daily. Ash plumes rose to altitudes of 1.5-2 km (3,300-6,600 ft) a.s.l. and drifted 180 km SW and SE during 20, 24, and 27 March. On 28 March ash plumes rose to altitudes of 2-2.5 km (6,600-8,200 ft) a.s.l. and drifted 100 km ESE. The Aviation Color Code remained at Orange.

Geologic 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, which is located immediately south of Karymsky volcano. The caldera enclosing Karymsky volcano formed about 7600-7700 radiocarbon years ago; construction of the Karymsky stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.

Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W  | Summit elev. 1222 m

During 26 March-1 April HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Gas emissions remained elevated. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas; smaller particles may have been dropped several kilometers away. At Pu'u 'O'o Crater, glow emanated from spatter cones on the N and S portions of the crater floor, and from the lava pond in the NE spatter cone. The Kahauale’a 2 lava flow, fed by the NE spatter cone, continued to advance, with breakout lava flows from the main stalled lobe, and burn adjoining forest. A satellite image acquired on 27 March showed active breakouts 5.5 and 8 km NE of Pu’u 'O'o.

Geologic summary: Kilauea volcano, which overlaps the east flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions of Kilauea are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.

Shiveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E  | Summit elev. 3283 m

KVERT reported that during 21-28 March lava-dome extrusion at Shiveluch was accompanied by ash explosions, incandescence, hot avalanches, and fumarolic activity. A bright thermal anomaly was detected daily in satellite images. The Aviation Color Code remained at Orange.

Geologic summary: The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km Shiveluch 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 of Shiveluch 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.

Sinabung, Indonesia
3.17°N, 98.392°E  | Summit elev. 2460 m

Based on webcam images, the Darwin VAAC reported that on 29 March an ash plume from Sinabung rose to an altitude of 4.3 km (14,000 ft) a.s.l. Meteorological cloud cover prevented satellite views. Gas emissions were noted on 30 March.

Geologic summary: Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical, 2460-m-high andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks of Sinabung in 1912. No confirmed historical eruptions were recorded prior to explosive eruptions during August-September 2010 that produced ash plumes to 5 km above the summit.

Tungurahua, Ecuador
1.467°S, 78.442°W  | Summit elev. 5023 m

IG reported that cloud cover occasionally prevented observations of Tungurahua during 26 March-1 April, although on clear days no surface activity was observed. Minor ashfall was reported in El Manzano (8 km SW) and Cahuaji on 26 March. Seismicity was at moderate levels and then declined during 28 March-1 April. Lahars on 31 March traveled down the Vascún (N) and Mapayacu (SW) drainages, carrying blocks up to 1 m in diameter in the latter drainage.

Geologic summary: Tungurahua, a steep-sided andesitic-dacitic stratovolcano that towers more than 3 km above its northern base, is one of Ecuador's most active volcanoes. Three major volcanic edifices have been sequentially constructed since the mid-Pleistocene over a basement of metamorphic rocks. Tungurahua II was built within the past 14,000 years following the collapse of the initial edifice. Tungurahua II itself collapsed about 3000 years ago and produced a large debris-avalanche deposit and a horseshoe-shaped caldera open to the west, inside which the modern glacier-capped stratovolcano (Tungurahua III) was constructed. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. Prior to a long-term eruption beginning in 1999 that caused the temporary evacuation of the city of Baños at the foot of the volcano, the last major eruption had occurred from 1916 to 1918, although minor activity continued until 1925.

Source: GVP

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