Active volcanoes in the world: April 2 - April 8, 2014

Active volcanoes in the world: April 2 - April 8, 2014

New activity/unrest was observed at 5 volcanoes from April 2 - April 8, 2014. Ongoing activity was reported for 7 volcanoes.

New activity/unrest: Copahue, Central Chile-Argentina border | Reventador, Ecuador | Shishaldin, Fox Islands (USA) | Tungurahua, Ecuador | Ubinas, Peru

Ongoing activity: Aira, Kyushu (Japan) | Etna, Sicily (Italy) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Paluweh, Indonesia | Shiveluch, Central Kamchatka (Russia) | Sinabung, Indonesia

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

On 4 April OVDAS-SERNAGEOMIN reported that activity at Copahue continued to fluctuate at an elevated level however did not indicate an impending eruption. The Alert Level was lowered to Yellow.

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.

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

IG reported that cloud cover occasionally prevented visual observations of Reventador during 2-8 April; activity remained high. A steam-and-ash plume rose 3 km and drifted E on 2 April, and a thermal camera detected hot material on the flanks. Four lava flows on the S and SE flanks were observed on 3 April. Ash emissions were observed the next day. On 5 April sporadic ash emissions rose 1 km and drifted W. On 6 April water vapor emissions with low amounts of ash rose 500 m and drifted NW. During 7-8 April lava flows continued to descend the S and SE flanks. On 8 April vapor emissions with small amounts of ash were observed.

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 elevated surface temperatures over Shishaldin's summit area were detected in satellite images during 2-8 April. No activity was detected in the seismic data. The webcam showed a steam plume rising from the crater on 6 April. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

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.

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

IG reported that seismicity at Tungurahua steadily increased from 2-4 April. On 2 April two small explosions, at 0757 and 2305, were accompanied by roaring and incandescent blocks rolling down the flanks. The second explosion ejected incandescent blocks and produced an ash plume that rose 600 m. Ashfall was reported in Cotaló (8 km NW) and Chacauco (NW). Although cloud cover often prevented visual observations, an ash plume generated by an explosion at 1455 on 4 April rose 2 km above the crater and drifted SW; ash fell in Choglontus (SW). On 4 April an explosion at 1810 lasted five minutes and generated pyroclastic flows that descended the NW and N flanks. An ash plume rose 10 km above the crater and drifted SW. Another explosion at 1816 lasted four minutes and possibly generated pyroclastic flows. Tephra up to 7 cm in diameter fell in Cusúa (8 km NW) and Píllaro. Constant tremor continued, interspersed with explosions. Strombolian activity was observed during the morning of 5 April. Steam-and-gas emissions with small amounts of ash rose less than 1 km and drifted W. At 1040 an ash plume rose 2 km. On 6 April ash plumes drifted W, and Strombolian activity ejected material that was deposited 1.5 km down the flanks. Ashfall was reported on 7 April in Bilbao (W) and Cevallos (23 km NW). On 8 April steam emissions with some ash rose 200 m and drifted SW. Minor ashfall was reported in Bilbao, El Manzano (8 km SW), Juive (7 km NNW), Mocha (25 km WNW), El Manzano. Large lahars descended the Achupashal (NW) and Confesionario drainages (WSW).

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.

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

IGP's Observatorio Volcanologico de Arequipa (IGP-OVA) reported that during 29 March-2 April seismicity at Ubinas increased significantly. The increase began at 1000 on 29 March with energetic tremor (indicating magma ascent and degassing) and small explosions. On 2 April harmonic tremor was detected. Gas-and-ash plumes rose 0.9-2.2 km above the crater and drifted SE and E. Minor ashfall was reported in Tonohaya (7 km SSE), San Miguel, and Ubinas (6.5 km SSE). Based on webcam views, the Buenos Aires VAAC reported that on 3 April gas-and-steam plumes possibly containing ash rose 6.1-7.3 km (20,000-24,000 ft) a.s.l. and dissipated around the crater. IGP-OVA noted that on 4 April there were 23 explosions detected; ash plumes drifted S and SE. During 5-7 April explosions generated ash plumes that rose as high as 2 km and drifted S and SW. During 7-8 April explosions also ejected incandescent fragments, up to 20 cm in diameter, no more than 1 km away. Ash plumes rose as high as 3 km.

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 during 31 March-4 April two explosions from Showa Crater at Aira Caldera’s Sakurajima volcano ejected tephra as far as 1,300 m. Incandescence from the crater was occasionally detected at night. The Alert Level remained at 3 (on a scale of 1-5). The Tokyo VAAC reported that. During 2 and 5-7 April plumes rose to altitudes of 1.5-2.4 km (5,000-8,000 ft) a.s.l. and drifted SW, S, SE, and E.

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.

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

INGV reported that during the night of 1-2 April emissions of minor lava flows from the NE base of Etna's New Southeast Crater (NSEC) cone decreased. Strombolian activity gradually intensified during the evening of 2 April and then decreased the next morning. Some collapses from the E flank of the cone were also observed that morning. Poor weather conditions prevented views of Etna for a few days, but by 7 April the lava flows had ceased and Strombolian activity had sharply declined. No activity was observed on 8 April.

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.

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

KVERT reported that volcanologists observed Vulcanian and Strombolian activity at Karymsky during 28 March-4 April. Satellite images detected a bright thermal anomaly on the volcano daily. Ash plumes rose to altitudes of 1-2.5 km (3,300-8,200 ft) a.s.l. and drifted 100 km SW and SE during 27-28 and 31 March, and 1-2 April. 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 2-8 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 continued to advance, with breakouts from the main stalled lobe, and burn adjoining forest. During an overflight on 7 April geologists observed that the farthest point of activity was 8.2 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.

Paluweh, Indonesia
8.32°S, 121.708°E, Summit elev. 875 m

PVMBG reported that observers at a post located in Kampung Ropa, Keliwumbu Village, noted that during January-5 April activity at Paluweh mainly consisted of white and gray fumarolic plumes rising at most 100 m above the lava dome and drifting W, N, and E. The report stated that the lava dome had not changed between September 2013 and March 2014 observations. Seismicity had decreased in November 2013 and remained low; the number of avalanches had also decreased. On 7 April the Alert Level was lowered to 2 (on a scale of 1-4).

Geologic summary: Paluweh volcano, also known as Rokatenda, forms the 8-km-wide island of Paluweh north of the volcanic arc that cuts across Flores Island. Although the volcano rises about 3000 m above the sea floor, its summit reaches only 875 m above sea level. The broad irregular summit region contains overlapping craters up to 900 m wide and several lava domes. Several flank vents occur along a NW-trending fissure. The largest historical eruption of Paluweh occurred in 1928, when a strong explosive eruption was accompanied by landslide-induced tsunamis and lava dome emplacement.

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

KVERT reported that during 28 March-4 April 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

PVMBG described activity at Sinabung during 23 March-8 April based on observations from a post in the Ndokum Siroga village, 8.5 km away. Dense white plumes rose at most 1.2 km above the lava dome. Lava had traveled 2.5 km down the flanks as of 6 April and was incandescent at various locations. Incandescent material originating from the edges of the lava dome and flow traveled up to 2 km S and 500 m SE. Tremor and volcanic earthquakes were detected, and signals representing avalanches from the unstable and still-growing dome decreased. Sulfur dioxide emissions varied but were relatively insignificant. The Alert Level was lowered to 3 (on a scale of 1-4). Visitors and tourists were prohibited from approaching the crater within a radius of 5 km on the S and SE flanks, and 3 km in the other directions.

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.

Source: GVP

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