New activity/unrest was reported for 6 volcanoes between December 28, 2016 and January 3, 2017. During the same period, ongoing activity was reported for 10 volcanoes.
New activity/unrest:Bezymianny, Central Kamchatka (Russia) | Bogoslof, Fox Islands (USA) | Cayambe, Ecuador | Ebeko, Paramushir Island (Russia) | Klyuchevskoy, Central Kamchatka (Russia) | Sabancaya, Peru.
Ongoing activity: Bagana, Bougainville (Papua New Guinea) | Bulusan, Luzon (Philippines) | Colima, Mexico | Copahue, Central Chile-Argentina border | Dukono, Halmahera (Indonesia) | Kilauea, Hawaiian Islands (USA) | Nevado del Ruiz, Colombia | Sheveluch, Central Kamchatka (Russia) | Sinabung, Indonesia | Turrialba, Costa Rica.
Bezymianny, Central Kamchatka (Russia)
55.972°N, 160.595°E, Elevation 2882 m
KVERT reported strong gas-and-steam emissions at Bezymianny during 23-30 December and a daily thermal anomaly over the volcano. The Aviation Color Code remained at Orange.
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.
Bogoslof, Fox Islands (USA)
53.93°N, 168.03°W, Elevation 150 m
On 27 December AVO noted that since there was no indication of elevated seismicity at Bogoslof during the previous day the Aviation Color Code (ACC) was lowered to Orange and the Volcano Alert Level (VAL) was lowered to Orange. AVO noted that there is no ground-based volcano monitoring equipment on Bogoslof; activity is monitored by satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on other islands.
An increase of volcanic tremor started to be detected at 1755 on 28 December with the largest burst, recorded at 1807 and lasting 50 minutes. Inclement weather prevented satellite confirmation of accompanying emissions. The report noted that this type of seismic activity had accompanied each of the previous explosions at Bogoslof since the eruption began last week, prompting AVO to issue a Volcano Activity Notice (VAN) and Volcano Observatory Notice for Aviation (VONA) in case there was an ash plume released.
Another increase in seismicity began at 1900 on 29 December and progressed, merging into a continuous tremor sequence indicative of a possible ash-producing eruption. At 2345 a 30-minute-long, ash-producing event began, with an ash plume possibly rising as high as 6.1 km (20,000 ft) a.s.l. that drifted NE. The ACC and VAL were raised to Red and Warning, respectively. A 45-minute-long explosive event began at 2230 on 30 December, indicated by seismic data and lightning strikes. Meteorological cloud cover prevented satellite views. No further explosions were detected afterward, so on 1 January 2017 the ACC was lowered to Orange and the VAL was lowered to Watch. Increased seismicity detected at 1353 on 2 January and lasting about 10 minutes likely indicated a relatively minor explosion; meteorological cloud cover prevented visual observations.
Geological 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.
0.029°N, 77.986°W, Elevation 5790 m
On 28 December IG reported continued anomalous seismic activity at Cayambe characterized by volcano-tectonic and long-period earthquakes located 2-8 km below the summit. As many as 40 earthquakes had been recorded each day for the previous two weeks and starting on 24 December that number again increased, especially for volcano-tectonic events. A swarm on 27 December consisted of 100 small-magnitude events. A strong sulfur odor persisted, and cracks in the glacier near the summit that climbers has recently reported were visible during an overflight. In addition, deformation on the flanks was detected in GPS data.
Geological summary: The massive compound andesitic-dacitic Cayambe stratovolcano is located on the isolated western edge of the Cordillera Real, east of the Inter-Andean Valley. The volcano, whose southern flank lies astride the equator, is capped by extensive glaciers, which descend to 4200 m on the eastern Amazonian side. The modern Nevado Cayambe, constructed to the east of older Pleistocene volcanic complexes, contains two summit lava domes located about 1.5 km apart, the western of which is the highest. Several other lava domes on the upper flanks have been the source of pyroclastic flows that reached the lower flanks. A prominent Holocene pyroclastic cone on the lower E flank, La Virgen, fed thick andesitic lava flows that traveled about 10 km E. Nevado Cayambe was recently discovered to have produced frequent explosive eruptions beginning about 4000 years ago, and to have had a single historical eruption during 1785-86.
Ebeko, Paramushir Island (Russia)
50.686°N, 156.014°E, Elevation 1103 m
KVERT reported that, according to observers in Severo-Kurilsk (Paramushir Island) about 7 km E, explosions at Ebeko produced ash plumes during 24-27 December that rose to an altitude of 2.5 km (8,200 ft) a.s.l. Minor ashfall was noted in Severo-Kurilsk on 23 and 26 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.
Klyuchevskoy, Central Kamchatka (Russia)
56.056°N, 160.642°E, Elevation 4754 m
Based on satellite and webcam images KVERT reported that explosions at Klyuchevskoy recorded on 1 January generated ash plumes that rose to an altitude of 5 km (16,400 ft) a.s.l. and drifted 114 km SE. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale).
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.
15.78°S, 71.85°W, Elevation 5967 m
On 28 December the Technical and Scientific Committee for volcanic risk management of the Arequipa region (comprised of five groups including IGP's OVS andINGEMMET's OVI) recommended that the Alert Level for Sabancaya be raised from Yellow to Orange based on increased activity detected during 8 November-26 December. A progressive increase in the number of explosions per day to 52 was noted along with the detection of 14 daily hybrid events. Harmonic tremor was recorded on 21, 24, and 25 December. Thermal anomalies were identified by the MIROVA system with the last one being recorded on 24 December. Gas-and-ash plumes rose as high as 4.5 km above the crater and drifted 40 km in different directions, affecting the villages of Maca, Achoma, Yanque, and Chivay, and areas to the W and NW including Huambo, Cabanaconde, Pinchollo, Lari, Tapay, and Madrigal. The public was warned to stay at least 12 km away from the volcano. An explosion on 2 January 2017 generated an ash plume that rose 2.5 km and drifted more than 30 km S and SW.
Geological 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.
Bagana, Bougainville (Papua New Guinea)
6.137°S, 155.196°E, Elevation 1855 m
Based on analyses of satellite imagery and model data, the Darwin VAAC reported that on 31 December ash plumes from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 35-55 km NE, E, and ESE. Only weak steam emissions were observed the next day.
Geological 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.
Bulusan, Luzon (Philippines)
12.77°N, 124.05°E, Elevation 1565 m
PHIVOLCS reported that a phreatic explosion occurred at 1440 on 29 December from a vent on Bulusan's upper SE flank. The seismic network recorded the event as an explosion-type earthquake that lasted about 16 minutes. A grayish ash plume rose 2 km above the vent and drifted WSW, causing minor amounts of ash to fall in areas downwind including the barangays of Cogon, Tinampo, Bolos, Umagom, Gulang-gulang, and Monbon of Irosin, and Caladgao and Guruyan of Juban. Residents of Guruyan, Juban, Monbon, and Tinampo of Irosin noted a sulfur odor. The Alert Level remained at 1, indicating abnormal conditions and a 4-km-radius Permanent Danger Zone (PDZ).
Geological summary: Luzon's southernmost volcano, Bulusan, was constructed along the rim of the 11-km-diameter dacitic-to-rhyolitic Irosin caldera, which was formed about 36,000 years ago. Bulusan lies at the SE end of the Bicol volcanic arc occupying the peninsula of the same name that forms the elongated SE tip of Luzon. A broad, flat moat is located below the topographically prominent SW rim of Irosin caldera; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of 1565-m-high Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
19.514°N, 103.62°W, Elevation 3850 m
Based on webcam and satellite images, information from the Mexico City MWO, and wind data the Washington VAAC reported that during 28 December 2016-3 January 2017 ash plumes from Colima rose to altitudes of 4.6-7.6 km (15,000-25,000 ft) a.s.l. and drifted as far as 135 km in multiple directions.
Geological summary: The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4320 m high point of the complex) on the north and the 3850-m-high historically active Volcán de Colima at the south. A group of cinder cones of late-Pleistocene age is located on the floor of the Colima graben west and east of the Colima complex. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the south, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.
Copahue, Central Chile-Argentina border
37.856°S, 71.183°W, Elevation 2953 m
Based on satellite and webcam images, the Buenos Aires VAAC reported that during 28-30 December continuous gas-and-ash emissions from Copahue rose to altitudes of 3.6-3.9 km (12,000-13,000 ft) a.s.l. and drifted S, SSE, ESE, and E.
Geological 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.
Dukono, Halmahera (Indonesia)
1.693°N, 127.894°E, Elevation 1229 m
Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 28-29 and 31 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 55 nm SE, S, and SSW.
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.
Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Elevation 1222 m
During 28 December 2017-3 January 2017 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 on most days. 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. On 31 December almost all of the Kamokuna lava delta had collapsed, along with a large section (180 m long and 70 m wide) of the older sea cliff E of the lava delta.
Geological 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.
Nevado del Ruiz, Colombia
4.892°N, 75.324°W, Elevation 5279 m
Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 27 December 2016-2 January 2017 seismicity at Nevado del Ruiz continued to indicate unrest. Some of the seismic signals were associated with gas-and-ash emissions, as confirmed by webcam images and officials in the Parque Nacional Natural los Nevados. A low-energy thermal anomaly was identified by the MIROVA system on 29 December. On 2 January a gas, water vapor, and ash plume rose 1.2 km above the crater rim and drifted between SW and NW directions. The Alert Level remained at III (Yellow; the second lowest level on a four-color scale).
Geological summary: Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers >200 sq km. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.
Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Elevation 3283 m
KVERT reported that during 23-30 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. Explosions recorded by a webcam on 24 December generated ash plumes that rose 6.5-7 km (21,300-23,000 ft) a.s.l. The Aviation Color Code remained at Orange.
Geological 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.
3.17°N, 98.392°E, Elevation 2460 m
Based on PVMBG observations, webcam views, satellite images, and wind data the Darwin VAAC reported that during 28 December 2016-1 January 2017 ash plumes from Sinabung rose 3-5.6 km (10,000-18,000 ft) a.s.l. and sometimes drifted SW. A thermal anomaly was detected in satellite images on 30 December.
Geological 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.
Turrialba, Costa Rica
10.025°N, 83.767°W, Elevation 3340 m
OVSICORI-UNA reported that at 2212 on 28 December and at 0335 on 30 December events at Turrialba generated plumes of unknown height due to poor visibility conditions. An event at 0801 on 30 December produced a dense and passive emission of ash that rose 300 m above the crater and drifted SW. An event later that same day, at 2001, produced a plume that was not visible.
Geological summary: Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive 3340-m-high Turrialba is exceeded in height only by Irazú, covers an area of 500 sq km, and is one of Costa Rica's most voluminous volcanoes. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.
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