Active volcanoes in the world: April 16 - April 22, 2014

Active volcanoes in the world: April 16 - April 22, 2014

New activity/unrest was observed at 4 volcanoes from April 16 - April 22, 2014. Ongoing activity was reported for 10 volcanoes.

New activity/unrest: Merapi, Central Java (Indonesia)  | Popocatépetl, Mexico  | Shishaldin, Fox Islands (USA)  | Tungurahua, Ecuador

Ongoing activity: Chirinkotan, Kuril Islands (Russia)  | Chirpoi, Kuril Islands (Russia)  | Dukono, Halmahera (Indonesia)  | Fuego, Guatemala  | Karymsky, Eastern Kamchatka (Russia)  | Kilauea, Hawaiian Islands (USA)  | Nishinoshima, Japan  | Shiveluch, Central Kamchatka (Russia)  | Sinabung, Indonesia  | Ubinas, Peru

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

Merapi, Central Java (Indonesia)
7.542°S, 110.442°E, Summit elev. 2968 m

PVMBG reported that Merapi observers at the Ngepos post noted white plumes rising 300 m above the lava dome on 15 April. Seismicity increased during 18-20 April. During 0426-0440 on 20 April an explosion occurred and rumbling was heard in areas as far as 8 km away. Ash plumes were observed from some observations posts, but foggy conditions prevented views from others. Based on satellite images and wind data, the Darwin VAAC reported that an ash plume rose to an altitude of 10.7 km (35,000 ft) a.s.l. and drifted 260 km WNW. PVMBG noted that ashfall was reported in areas within 15 km S, SW, and W. The Alert Level remained at 1 (on a scale of 1-4).

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.

Popocatépetl, Mexico
19.023°N, 98.622°WSummit elev. 5426 m

CENAPRED reported that during 15-22 April seismicity at Popocatépetl indicated continuing emissions of water vapor, gas, and occasional small amounts of ash. Cloud cover sometimes prevented visual observations. Slight nighttime incandescence was observed. Explosions recorded at 0729 and 1004 on 20 April, at 0758 and 1049 on 21 April, and at 2019 on 22 April produced plumes with minor ash content that rose around 1 km above the crater and drifted NE and NW. Crater incandescence increased when the explosions occurred. The Alert Level remained at to Yellow, Phase Two.

Geologic summary: Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 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 from Popocatépetl 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 precolumbian time.

Shishaldin, Fox Islands (USA)
54.756°N, 163.97°WSummit elev. 2857 m

AVO reported that although cloud cover often prevented web-cam and satellite observations of Shishaldin's summit area during 16-22 April, weakly elevated surface temperatures and minor steaming were occasionally observed. No significant changes were detected in seismic data. 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°WSummit elev. 5023 m

IG reported that activity at Tungurahua remained at moderate-to-high levels during 16-22 April. Although cloud cover sometimes prevented visual observations of the crater, ash plumes were observed on most days and drifted mostly WSW. Crater incandescence was often observed at night and roaring was reported from local areas. During 16-19 April ashfall was reported in Mocha (25 km WNW), Tizaleo (29 km NW), Bilbao (W), Cusúa (8 km NW), Choglontus (SW), El Manzano (8 km SW), and Palictahua. On 17 April ash plumes rose 3 km and drifted WSW. Incandescent blocks traveled 1 km down the W flank. On 18 April ash plumes rose 2 km and drifted WSW. At night Strombolian activity ejected incandescent blocks that again traveled 1 km down the W flank. Ash plumes rose 3-3.5 km during 19-20 April.

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.

Ongoing activity

Chirinkotan, Kuril Islands (Russia)
48.98°N, 153.48°ESummit elev. 724 m

SVERT reported that satellite images of Chirinkotan showed a thermal anomaly on 14, 15, and 17 April, and gas-and-steam emissions on 20 April. Cloud cover obscured views during 16, 18-19, and 21 April. 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°ESummit elev. 742 m

SVERT reported that satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly on 14, 16, and 18 April. Cloud cover obscured views on the other days during 15-21 April. 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°ESummit elev. 1335 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 16-19 and 21-22 April ash plumes from Dukono rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted 65-150 km SE, ESE, and E.

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.

Fuego, Guatemala
14.473°N, 90.88°WSummit elev. 3763 m

INSIVUMEH noted in special reports that during 20-22 April explosions from Fuego generated ash plumes that rose 750 m above the crater and drifted 10-12 km NW, W, SW, and S. Ashfall was reported in villages downwind, including Panimaché (8 km SW), Morelia (9 km SW), and Santa Sofía (12 km SW). Explosions were audible up to 30 km away, and shock waves detected more than 15 km away vibrated houses in Panimaché, Morelia, Santa Sofía, and other areas. Avalanches of blocks reached vegetated areas.

Geologic summary: Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3763-m-high Fuego and its twin volcano to the north, Acatenango. Construction of Meseta volcano dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta volcano 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 Acatenango. In contrast to the mostly andesitic Acatenango volcano, eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

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

KVERT reported that Vulcanian and Strombolian activity continued at Karymsky during 11-17 April. Satellite images detected a thermal anomaly on the volcano during 15-17; cloud cover obscure views on the other days. 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°WSummit elev. 1222 m

During 16-22 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. On 18 April geologists noted that the farthest point of activity was 7.5 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.

Nishinoshima, Japan
27.247°N, 140.874°ESummit elev. 25 m

Based on satellite images, the Tokyo VAAC reported that on 18 April a possible eruption from Nishinoshima produced a plume that rose 2.1 km (7,000 ft) a.s.l. and drifted E.

Geologic summary: The small island of Nishinoshima was recently enlarged when it was joined to several new islands that formed during an eruption in 1973-74. Water discoloration has been observed on several occasions since. The 700-m-wide island is the summit of a massive submarine volcano that has prominent satellitic peaks to the S, W, and NE. The summit of the southern cone rises to within 214 m of the sea surface 9 km SSE.

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

KVERT reported that during 4-11 April lava-dome extrusion onto Shiveluch’s SE flank was accompanied by ash explosions, incandescence, hot avalanches, and fumarolic activity. Satellite images showed a bright thermal anomaly daily, and ash plumes that drifted SE at an altitude of 4 km (13,000 ft) a.s.l. during 16-17 April. 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°ESummit elev. 2460 m

Based on webcam images, satellite images, and wind data, the Darwin VAAC reported that on 22 April an ash plume from Sinabung rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted almost 40 km W.

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.

Ubinas, Peru
16.355°S, 70.903°WSummit elev. 5672 m

IGP's Observatorio Volcanologico de Arequipa (IGP-OVA) and Observatorio Vulcanológico del INGEMMET (OVI) reported that 21 moderate explosions at Ubinas were detected during 11-16 April along with a sharp increase in seismicity; the magnitude and frequency of explosions increased during 14-16 April. Multiple explosions during 16-22 April ejected incandescent tephra, and generated plumes of gas, water vapor, and ash that rose at most 5 km above the crater. Ash fell in multiple areas in almost all directions, but was most concentrated to the S, SW, and W; towns affected included Querapi (4 km S), Ubinas (6.5 km SSE), Sacuaya, Huatagua (14 km SE), Escacha, Quinistaquillas, San Miguel (10 km SE), Tonohaya, and Matalaque. On 18 April at 1836 a significant gas-and-ash emission was accompanied by the ejection of incandescent blocks that landed up to 2 km from the crater. Explosions on 19 and 22 April ejected incandescent tephra, 20-30 cm in diameter, up to 2.5 km away from the crater. Fine ash fell in Omate, 37 km SSW. According to a news article, an evacuation of 4,000 residents was underway, along with nearly 30,000 livestock.

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.

Source: GVP

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