New activity/unrest was reported for 3 volcanoes between January 18 and 24, 2017. During the same period, ongoing activity was reported for 11 volcanoes.
New activity/unrest: Bogoslof, Fox Islands (USA) | Ebeko, Paramushir Island (Russia) | Takawangha, Andreanof Islands (USA).
Ongoing activity: Bagana, Bougainville (Papua New Guinea) | Colima, Mexico | Dukono, Halmahera (Indonesia) | Kilauea, Hawaiian Islands (USA) | Klyuchevskoy, Central Kamchatka (Russia) | Masaya, Nicaragua | Pacaya, Guatemala | Sabancaya, Peru | Sheveluch, Central Kamchatka (Russia) | Sinabung, Indonesia | Turrialba, Costa Rica.
Bogoslof, Fox Islands (USA)
53.93°N, 168.03°W, Elevation 150 m
AVO reported that an explosive event at Bogoslof began at about 1320 on 18 January, generating an ash plume that rose at least to an altitude of 9.4 km (31,000 ft) a.s.l. and drifted NE. The dark (ash-rich) plume was identified in satellite images and observed by a pilot, and produced lightning strikes and infrasound signals detected by sensors in Sand Point and Dillingham. Analysis of a satellite image suggested the presence of very hot material (lava) at the surface immediately surrounding the vent, which was the first such observation since the beginning of the eruption. AVO raised the Aviation Color Code (ACC) to Red and the Volcano Alert Level (VAL) to Warning. A second lower-altitude cloud was visible in satellite images around 1400, likely corresponding with an increase in seismic tremor that occurred from 1340-1355. The ACC was lowered to Orange and the VAL was lowered to Watch the next day.
Another explosion was detected at 1317 on 20 January, following an approximately 30-minute-long increase in seismic activity, based on seismic data and lightning detected from the World Wide Lightning Location Network. Pilots observed an ash plume rising to an altitude of 11 km (36,000 ft) a.s.l. and drifting SE. Satellite images indicated an ice-rich plume and lava present at the vent. The ACC was raised to Red and the VAL was raised to Warning, but were again lowered one level to Orange and Watch, respectively, the next day. Several lightning strikes north of Bogoslof indicated that an explosive event began at 1409 on 22 January. An ash plume identified in satellite images rose to an altitude of 9.1 km (30,000 ft) a.s.l. The ACC was raised to Red and the VAL was raised to Warning, and again lowered one level the next day. Following a period of increasing seismicity, an explosive event began at 0453 on 24 January, as indicated in seismic data and lightning detection, prompting AVO to raise the ACC to Red and the VAL to Warning. Seven minutes later an ice-rich plume which likely contained ash rose too altitudes of 7.6-10.7 km (25,000-35,000 ft) a.s.l. and drifted E.
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.
Ebeko, Paramushir Island (Russia)
50.686°N, 156.014°E, Elevation 1103 m
On 19 January KVERT reported that activity at Ebeko had decreased significantly, and only steam-and-gas emissions had been observed since 12 January. The Aviation Color Code was lowered to Green (the lowest level on a four-color scale). According to observers in Severo-Kurilsk (Paramushir Island) about 7 km E, ash plumes rose to an altitude of 2 km (6,600 ft) a.s.l. and drifted 3 km SW on 19 January. The Aviation Color Code was raised to 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.
Takawangha, Andreanof Islands (USA)
51.873°N, 178.006°W, Elevation 1449 m
AVO reported that an energetic earthquake swarm on Tanaga Island began on 23 January, with earthquakes located 6-7 km ESE of Takawangha volcano, and was possibly due to brittle failure in the surrounding rock caused by magma movement. AVO raised the Aviation Color Code to Yellow and Alert Level to Advisory.
Geological summary: Takawangha is a 1449-m-high, youthful volcano with an ice-filled caldera on northern Tanaga Island, near the western end of the Andreanof Islands. Takawangha lies across a saddle from historically active Tanaga volcano to the west; older, deeply eroded volcanoes lie adjacent to Takawangha on the east. The summit of the dominantly basaltic to basaltic-andesite volcano is largely ice covered, with the exception of five Holocene craters that during the last few thousand years produced explosive eruptions and lava flows that reached the lower flanks of the volcano. No historical eruptions are known from Takawangha, although radiocarbon dating indicates explosive eruptions have occurred within the past several hundred years.
Bagana, Bougainville (Papua New Guinea)
6.137°S, 155.196°E, Elevation 1855 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 19 January an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE. On 24 January ash plumes visible in satellite images and observed by a pilot rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l and drifted almost 140 km NE.
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.
19.514°N, 103.62°W, Elevation 3850 m
The Unidad Estatal de Protección Civil de Colima reported that at 0027 on 18 January a moderate-to-large explosion at Colima ejected incandescent material as far as 2 km onto the W, SW, SE, and N flanks.
Based on webcam and satellite images, the Mexico City MWO, and pilot observations, the Washington VAAC reported that during 18-24 January ash plumes from Colima rose to altitudes of 4.1-6.7 km (15,000-25,000 ft) a.s.l. and drifted in multiple directions. On 19 January explosions were recorded by the webcam and noted by the Jalisco Civil protection agency; ashfall was also reported in Comala and Cuauhtémoc by the agency. A strong thermal anomaly was identified in satellite images. Remnant ash clouds were centered about 350 km SE on 20 January and about 185 km S on 22 January. A large ash plume rose to an altitude of 10.7 km (35,000 ft) a.s.l. on 23 January and drifted NE.
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.
Dukono, Halmahera (Indonesia)
1.693°N, 127.894°E, Elevation 1229 m
Based on analyses of satellite imagery, model data, and notices from PVMBG, the Darwin VAAC reported that during 18-24 January ash plumes from Dukono rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted S, SW, W, and NW.
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 18-24 January HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. 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 at Kamokuna. All surface flows were active within 2.4 km of Pu'u 'O'o.
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.
Klyuchevskoy, Central Kamchatka (Russia)
56.056°N, 160.642°E, Elevation 4754 m
KVERT reported that during 13-20 January gas-and-steam emissions from Klyuchevskoy sometimes contained minor amounts of ash. Satellite images showed a daily thermal anomaly over the volcano. On 22 January an ash plume rose to altitudes of 5-5.5 km (16,400-18,000 ft) a.s.l. and drifted 45 km E. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale), but was again lowered to Yellow on 24 January.
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.
11.984°N, 86.161°W, Elevation 635 m
Based on satellite images, the Washington VAAC reported that on 21 January a possible emission from Masaya with minor ash content drifted almost 25 km NW.
Geological summary: Masaya is one of Nicaragua's most unusual and most active volcanoes. It lies within the massive Pleistocene Las Sierras pyroclastic shield volcano and is a broad, 6 x 11 km basaltic caldera with steep-sided walls up to 300 m high. The caldera is filled on its NW end by more than a dozen vents that erupted along a circular, 4-km-diameter fracture system. The twin volcanoes of Nindirí and Masaya, the source of historical eruptions, were constructed at the southern end of the fracture system and contain multiple summit craters, including the currently active Santiago crater. A major basaltic Plinian tephra erupted from Masaya about 6500 years ago. Historical lava flows cover much of the caldera floor and have confined a lake to the far eastern end of the caldera. A lava flow from the 1670 eruption overtopped the north caldera rim. Masaya has been frequently active since the time of the Spanish Conquistadors, when an active lava lake prompted attempts to extract the volcano's molten "gold." Periods of long-term vigorous gas emission at roughly quarter-century intervals cause health hazards and crop damage.
14.381°N, 90.601°W, Elevation 2552 m
INSIVUMEH reported that at night during 21-22 January incandescence was reflected from emissions above Pacaya’s Mackenney cone. In a 24 January report, INSIVUMEH noted that gas-and-ash emissions had continued, with deposits filling in the crater on top of the cone. Nighttime incandescence continued to be observed.
Geological summary: Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. This complex basaltic volcano was constructed just outside the southern topographic rim of the 14 x 16 km Pleistocene Amatitlán caldera. A cluster of dacitic lava domes occupies the southern caldera floor. The post-caldera Pacaya massif includes the ancestral Pacaya Viejo and Cerro Grande stratovolcanoes and the currently active Mackenney stratovolcano. Collapse of Pacaya Viejo between 600 and 1500 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (Mackenney cone) grew. A subsidiary crater, Cerro Chino, was constructed on the NW somma rim and was last active in the 19th century. During the past several decades, activity has consisted of frequent strombolian eruptions with intermittent lava flow extrusion that has partially filled in the caldera moat and armored the flanks of Mackenney cone, punctuated by occasional larger explosive eruptions that partially destroy the summit of the growing young stratovolcano.
15.78°S, 71.85°W, Elevation 5967 m
Based on webcam and satellite views, the Buenos Aires VAAC reported that sporadic gas-and-ash puffs rose from Sabancaya during 17-24 January. Meteorological cloud cover sometimes prevented observations.
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.
Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Elevation 3283 m
KVERT reported that during 13-20 January 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. 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, satellite images, and wind data, the Darwin VAAC reported that during 19-20, 22, and 24 January ash plumes from Sinabung rose 3.9-4.9 km (13,000-16,000 ft) a.s.l. and drifted NW, SW, and SE.
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
Based on webcam and satellite views, the Washington VAAC reported that on 22 January an ash plume from Turrialba rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted E.
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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