The Weekly Volcanic Activity Report: December 18 - 24, 2019

The Weekly Volcanic Activity Report: December 18 - 24, 2019

New activity/unrest was reported for 3 volcanoes from December 18 to 24, 2019. During the same period, ongoing activity was reported for 10 volcanoes.

New activity/unrest: Bezymianny, Central Kamchatka (Russia) | Semisopochnoi, United States | White Island, North Island (New Zealand).

Ongoing activity: Aira, Kyushu (Japan) | Dukono, Halmahera (Indonesia) | Ebeko, Paramushir Island (Russia) | Fuego, Guatemala | Karangetang, Siau Island (Indonesia) | Kirishimayama, Kyushu (Japan) | Klyuchevskoy, Central Kamchatka (Russia) | Sangeang Api, Indonesia | Sheveluch, Central Kamchatka (Russia) | Shishaldin, Fox Islands (USA).

New activity/unrest

Bezymianny, Central Kamchatka (Russia)

55.972°N, 160.595°E, Elevation 2882 m

Activity at Bezymianny remained elevated during 13-20 December; nighttime crater incandescence, strong fumarolic emissions, and a lava flow on the W flank of the lava dome were visible. The temperature of a thermal anomaly had continued to increase. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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. This volcano is located within the Volcanoes of Kamchatka, a UNESCO World Heritage property.

Semisopochnoi, United States

51.93°N, 179.58°E, Elevation 1221 m

AVO reported that ash plumes below 1.5 km (5,000 ft) a.s.l. from Semisopochnoi were identified in satellite images on 14 and 17 December; ash plumes on 17 December drifted about 15 km SE. During 17-20 December seismicity was characterized by tremor bursts and small explosions, though cloudy weather conditions prevented visual confirmation. Elevated seismicity was recorded on 21 December. Nothing significant was detected during 22-24 December. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Geological summary: Semisopochnoi, the largest subaerial volcano of the western Aleutians, is 20 km wide at sea level and contains an 8-km-wide caldera. It formed as a result of collapse of a low-angle, dominantly basaltic volcano following the eruption of a large volume of dacitic pumice. The high point of the island is 1221-m-high Anvil Peak, a double-peaked late-Pleistocene cone that forms much of the island's northern part. The three-peaked 774-m-high Mount Cerberus volcano was constructed during the Holocene within the caldera. Each of the peaks contains a summit crater; lava flows on the northern flank of Cerberus appear younger than those on the southern side. Other post-caldera volcanoes include the symmetrical 855-m-high Sugarloaf Peak SSE of the caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake in the NE part of the caldera. Most documented historical eruptions have originated from Cerberus, although Coats (1950) considered that both Sugarloaf and Lakeshore Cone within the caldera could have been active during historical time. This volcano is located within the Aleutian Islands, a UNESCO Biosphere Reserve property.

White Island, North Island (New Zealand)

37.52°S, 177.18°E, Elevation 321 m

GeoNet reported that during 18-23 December the level of volcanic tremor at White Island remained low and gas-and-steam plumes were strongly emitted from the new vent area. The highest-temperature emissions were more than 650 degrees Celsius measured during an overflight on 19 December. Volcanologists also measured about 1,300 tons/day of sulfur dioxide, slightly lower than 12 December measurements of about 1,730 tons/day. A small part of the SW slope of the 1914 landslide (inside the crater rim and opposite the former viewing area) had collapsed into the crater lake and active vent area, leaving a scarp 12 m high. The area had been unstable prior to the 9 December eruption. According to the New Zealand Police the death toll from the 9 December eruption had reached 17. Two people remained missing; the search was suspended on 24 December.

Geological summary: Uninhabited 2 x 2.4 km White Island, one of New Zealand's most active volcanoes, is the emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The island consists of two overlapping andesitic-to-dacitic stratovolcanoes; the summit crater appears to be breached to the SE, because the shoreline corresponds to the level of several notches in the SE crater wall. Volckner Rocks, four sea stacks that are remnants of a lava dome, lie 5 km NNE. Intermittent moderate phreatomagmatic and strombolian eruptions have occurred throughout the short historical period beginning in 1826, but its activity also forms a prominent part of Maori legends. Formation of many new vents during the 19th and 20th centuries has produced rapid changes in crater floor topography. Collapse of the crater wall in 1914 produced a debris avalanche that buried buildings and workers at a sulfur-mining project.

Ongoing activity

Aira, Kyushu (Japan)

31.593°N, 130.657°E, Elevation 1117 m

JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 16-23 December. There were 16 explosions and nine non-explosive eruptive events detected by the seismic network. Ash plumes rose as high as 2.5 km above the crater rim and material was ejected 0.5-1.3 km away from the crater. 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, Elevation 1229 m

Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 18-24 December ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted E, ESE, and SE. The Alert Level remained at 2 (on a scale of 1-4), and the public was 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, Elevation 1103 m

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 15-17 December that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted E, causing ashfall in Severo-Kurilsk during 16-17 December. 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.

Fuego, Guatemala

14.473°N, 90.88°W, Elevation 3763 m

INSIVUMEH reported that there were 8-18 explosions per hour recorded at Fuego during 18-24 December, generating ash plumes that rose as high as 1 km above the crater rim and drifted 10-205 km S, SW, and W. Ashfall was reported in several areas downwind including Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché I and II (8 km SW), Finca Palo Verde, San Pedro Yepocapa (8 km NW), Sangre de Cristo (8 km WSW), and El Porvenir (8 km ENE). Explosions sometimes produced shock waves that rattled houses in nearby communities. Incandescent material was ejected 100-300 m high and caused avalanches of material that occasionally traveled long distances (reaching vegetated areas) down the Seca (W), Taniluyá (SW), Ceniza (SSW), Trinidad (S), and Las Lajas (SE) ravines. Incandescent material traveled about 300 m down the Seca drainage during 23-24 December.

Geological summary: Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Karangetang, Siau Island (Indonesia)

2.781°N, 125.407°E, Elevation 1797 m

PVMBG reported that during 16-22 December lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.8 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 150 m above the summit. Incandescence from both summit craters was visible at night. The Alert Level remained at 2 (on a scale of 1-4).

Geological summary: Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi island. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia's most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented in the historical record (Catalog of Active Volcanoes of the World: Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows.

Kirishimayama, Kyushu (Japan)

31.934°N, 130.862°E, Elevation 1700 m

JMA reported that the increase in the number of volcanic earthquakes with hypocenters just below Shinmoedake (Shinmoe peak), a stratovolcano of the Kirishimayama volcano group, only lasted during 17-18 November. The number of volcanic earthquakes was low after that and no other data indicated increased activity. Scientists noted no changes to geothermal areas on the crater floor and below cracks on the W flank during a field survey on 12 December. The Alert Level was lowered to 1 (on a scale of 1-5) on 20 December.

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.

Klyuchevskoy, Central Kamchatka (Russia)

56.056°N, 160.642°E, Elevation 4754 m

KVERT reported that a weak thermal anomaly over Klyuchevskoy was identified in satellite images during 12-15 and 17 December, and Strombolian activity was visible during 13-15 and 17 December. Gas-and-steam plumes rose to 5-5.5 km (16,400-18,000 ft) a.s.l. and drifted 45 km NE on 14 and 19 December. The Aviation Color Code remained at Orange.

Geological summary: Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters. This volcano is located within the Volcanoes of Kamchatka, a UNESCO World Heritage property.

Sangeang Api, Indonesia

8.2°S, 119.07°E, Elevation 1912 m

The Darwin VAAC reported that during 18-19 December discrete minor ash emissions from Sangeang Api rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted W. The Alert Level remained at 2 (on a scale of 1-4).

Geological summary: Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-tranchyandesitic volcanic cones, Doro Api and Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent historical eruptions have been recorded since 1512, most of them during in the 20th century.

Sheveluch, Central Kamchatka (Russia)

56.653°N, 161.36°E, Elevation 3283 m

KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 13-20 December. 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.

Shishaldin, Fox Islands (USA)

54.756°N, 163.97°W, Elevation 2857 m

AVO reported that the eruption at Shishaldin continued during 18-24 December. Elevated surface temperatures were identified in satellite images, though clouds sometimes prevented views. Seismicity remained elevated and was characterized by ongoing tremor and periodic weak explosions. Satellite imagery indicated that the active summit cone had grown after collapsing the week before. Minor ash emissions drifted S on 19 December and E at 4.6 km (15,000 ft) a.s.l. on 21 December. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Geological 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, it 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. There are 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. This volcano is located within the Aleutian Islands, a UNESCO Biosphere Reserve property.

Source: GVP

Comments

Alanna 11 months ago

There are 23 currently active volcanoes in the word according to Volcanodiscovery.com I live near Sangay in Ecuador and the sky was filled with ash yesterday...

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