Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx)
URL: http://www.volcano.si.
New Activity/Unrest: Bezymianny, Central Kamchatka (Russia) | Bogoslof, Fox Islands (USA) | Ebeko, Paramushir Island (Russia) | Klyuchevskoy, Central Kamchatka (Russia) | Langila, New Britain (Papua New Guinea)
Ongoing Activity: Bagana, Bougainville (Papua New Guinea) | Copahue, Central Chile-Argentina border | Dukono, Halmahera (Indonesia) | Fuego, Guatemala | Kilauea, Hawaiian Islands (USA) | Sabancaya, Peru | Sheveluch, 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 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
Bezymianny | Central Kamchatka (Russia) | 55.972°N, 160.595°E | Summit elev. 2882 m
KVERT reported strong gas-and-steam emissions at Bezymianny during 16-23 December; a gas-and-steam plume drifted about 60 km SW on 18 December. A daily thermal anomaly was detected over the volcano. The Aviation Color Code remained at Orange.
Geologic 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/
Bogoslof | Fox Islands (USA) | 53.93°N, 168.03°W | Summit elev. 150 m
AVO reported that the explosive eruption at Bogoslof, which was reported by several pilots around 1530 on 20 December and produced an ash plume that rose to 10.3 km (34,000 ft) a.s.l., lasted about 30 minutes. The ash plume detached and dispersed S. AVO had raised the Aviation Color Code (ACC) to Red and the Volcano Alert Level (VAL) to Warning, but since no further activity was detected or observed the ACC was lowered to Orange and the VAL was lowered to Watch. On 21 December periods of discrete earthquakes and continuous seismic tremor were recorded by instruments on nearby volcanoes. At 1610 an explosive eruption detected in satellite data and by seismic instruments on nearby islands again lasted about 30 minutes. An ash plume rose to an altitude of 10.7 km (35,000 ft) a.s.l. and drifted N. The ACC and VAL were raised to Red and Warning, respectively. Seismicity declined rapidly afterward and remained low; the ACC was lowered to Orange and the VAL was lowered to Watch. Strong continuous seismic activity started abruptly at about 1340 on 22 December.
AVO noted that the eruption had dramatically changed the island. Satellite images showed that a small new island had formed just offshore of the NE end of the main island, the previous shore and much of the NE side of Bogoslof Island adjacent to the new island had been mostly removed (and was likely the site of the new, underwater vent), and deposition of material had occurred on the W side of the island.
An explosion occurred at 0930 on 23 December. A Coast Guard ship in the vicinity reported ash emissions, lightning, and ejected lava and fragmented material. The ash plume rose to an altitude below 9.1 km (30,000 ft) a.s.l. Coast Guard observers noted that ash emission subsided around 1037. The ACC/VAL were raised to Red/Warning. On 24 December seismic unrest was periodically detected by nearby island networks, but levels were generally low. The ACC was lowered to Orange and the VAL was lowered to Watch. A period of tremor detected in the evening on 25 December may have been associated with a minor, low-level ash emission (below 3 km or 10,000 ft a.s.l.); several lightning strikes in the area were recorded. Lightning strikes, seismic data, and satellite images indicated a continuing eruption that began at 1405 on 26 December. An ash plume rose to an altitude of 9.1 km (30,000 ft) a.s.l. and drifted WSW. The ACC/VAL were again raised to Red/Warning.
Geologic Summary. Bogoslof is the emergent summit of a submarine volcano that lies 40 km north of the main Aleutian arc. It rises 1500 m above the Bering Sea floor. Repeated construction and destruction of lava domes at different locations during historical time has greatly modified the appearance of this "Jack-in-the-Box" volcano and has introduced a confusing nomenclature applied during frequent visits of exploring expeditions. The present triangular-shaped, 0.75 x 2 km island consists of remnants of lava domes emplaced from 1796 to 1992. Castle Rock (Old Bogoslof) is a steep-sided pinnacle that is a remnant of a spine from the 1796 eruption. Fire Island (New Bogoslof), a small island located about 600 m NW of Bogoslof Island, is a remnant of a lava dome that was formed in 1883.
Source: US Geological Survey Alaska Volcano Observatory (AVO) http://www.avo.alaska.
Ebeko | Paramushir Island (Russia) | 50.686°N, 156.014°E | Summit elev. 1103 m
KVERT reported that, according to observers in Severo-Kurilsk (Paramushir Island) about 7 km E, gas-and-steam plumes containing a small amount of ash rose from Ebeko to an altitude of 1.5 km (4,900 ft) a.s.l. and drifted 8 km N and NE on 17 and 20 December. Minor amounts of ash fell in Severo-Kurilsk during 18-22 December. Ash plumes rose as high as 2 km (6,600 ft) a.s.l. on 27 December. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale).
Geologic 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/
Klyuchevskoy | Central Kamchatka (Russia) | 56.056°N, 160.642°E | Summit elev. 4754 m
On 26 December KVERT reported that a weak thermal anomaly over Klyuchevskoy had been detected after the April-November eruption. Gas-and-steam plumes sometimes contained small amounts of ash. The Aviation Color Code was raised to Yellow (the second lowest on a four-color scale).
Geologic 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/
Langila | New Britain (Papua New Guinea) | 5.525°S, 148.42°E | Summit elev. 1330 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 21-24 December ash plumes from Langila rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted N, NW, S, and SE.
Geologic Summary. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower eastern flank of the extinct Talawe volcano. Talawe is the highest volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila volcano was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the north and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit of Langila. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/
Ongoing Activity
Bagana | Bougainville (Papua New Guinea) | 6.137°S, 155.196°E | Summit elev. 1855 m
Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 22 and 25-27 December ash plumes from Bagana rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted 45-85 km S, SW, and WSW.
Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. This massive symmetrical cone was largely constructed by an accumulation of viscous andesitic lava flows. The entire edifice could have been constructed in about 300 years at its present rate of lava production. Eruptive activity is frequent and characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50 m thick with prominent levees that descend the flanks on all sides.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/
Copahue | Central Chile-Argentina border | 37.856°S, 71.183°W | Summit elev. 2953 m
Based on satellite and webcam images, the Buenos Aires VAAC reported that during 21-23 December gas-and-ash plumes from Copahue rose to altitudes of 3.6-3.9 km (12,000-13,000 ft) a.s.l. and drifted SE and ESE.
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.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.smn.gov.ar/
Dukono | Halmahera (Indonesia) | 1.693°N, 127.894°E | Summit elev. 1229 m
Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 21-26 December ash plumes from Dukono rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted as far as 185 km NE, ENE, E, and SE.
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. 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.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/
Fuego | Guatemala | 14.473°N, 90.88°W | Summit elev. 3763 m
In a special bulletin from 21 December, INSIVUMEH reported the beginning of the 16th Strombolian episode in 2016 at Fuego. Ash plumes rose 1.5 km above the crater and drifted 18 km S, SW, W, and NW, and ashfall was reported in nearby areas including Morelia (9 km SW), Santa Sofía (12 km SW), Panimaché I and II (8 km SW), and Sangre de Cristo (8 km WSW). Lava fountains rose 200-300 m above the crater and fed three lava flows: the first traveled 2.5 km W down the Santa Teresa drainage, the second traveled 2 km SW down the Taniluyá Canyon, and the last traveled 1.8 km SE down the Las Lajas drainage. Shock waves from explosions rattled structures within a 12-km radius. During 24-27 December weak explosions generated ash plumes that rose 450-750 m and drifted 5-10 km W and SW.
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 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 Acatenango. In contrast to 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.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.
Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m
During 21-27 December HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent, and was visible from the Jaggar Museum overlook. Webcams recorded incandescence from long-active sources within Pu'u 'O'o Crater and from a vent high on the NE flank of the cone. The 61G lava flow, originating from a vent on Pu'u 'O'o Crater's E flank, continued to enter the ocean near Kamokuna at the easternmost lava delta. An active branch of 61G remained active E of Pu'u 'O'o and advanced slowly E at a rate of only a few tens of meters per day.
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 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.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/
Sabancaya | Peru | 15.787°S, 71.857°W | Summit elev. 5960 m
Based on webcam and satellite views, the Buenos Aires VAAC reported that during 21-26 December intermittent, strong ash puffs from Sabancaya rose 6.4-7.6 km (25,000-28,000 ft) a.s.l. and drifted in multiple directions.
Geologic Summary. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of historical eruptions date back to 1750.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.smn.gov.ar/
Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m
KVERT reported that during 10-16 December lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome, and ash plumes that drifted 370 km NNW during 16-20 December. A webcam recorded an explosion on 19 December with an ash plume that rose 7 km a.s.l. The Aviation Color Code remained at Orange.
Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/
Sinabung | Indonesia | 3.17°N, 98.392°E | Summit elev. 2460 m
Based on PVMBG observations, webcam views, and satellite images, the Darwin VAAC reported that on 21-22 and 26-27 December ash plumes from Sinabung rose 3.3-6.2 km (11,000-20,000 ft) a.s.l. and drifted SE and NW.
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 andesitic-to-dacitic edifice 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 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: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/
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