New activity/unrest was observed at 4 volcanoes between February 1 and 7, 2017. During the same period, ongoing activity was observed at 10 volcanoes.
New activity/unrest: Chirinkotan, Kuril Islands (Russia) | Cleveland, Chuginadak Island (USA) | Piton de la Fournaise, Reunion Island (France) | Takawangha, Andreanof Islands (USA).
Ongoing activity: Bogoslof, Fox Islands (USA) | Colima, Mexico | Dukono, Halmahera (Indonesia) | Ebeko, Paramushir Island (Russia) | Fuego, Guatemala | Kilauea, Hawaiian Islands (USA) | Sabancaya, Peru | Sheveluch, Central Kamchatka (Russia) | Sinabung, Indonesia | Turrialba, Costa Rica.
Chirinkotan, Kuril Islands (Russia)
48.98°N, 153.48°E, Elevation 724 m
On 6 February SVERT noted that the Aviation Color Code for Chirinkotan had been lowered to Green (lowest level on a four-color scale).
Geological 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.
Cleveland, Chuginadak Island (USA)
52.825°N, 169.944°W, Elevation 1730 m
On 3 February AVO reported that recent satellite data indicated that a new lava dome had been extruded, and partially filled Cleveland's summit crater. The new dome is about 70 m in diameter, similar in size to previous lava domes that have developed on the crater floor. Since explosive activity has sometimes followed lava-dome extrusion, AVO increased the Aviation Color Code to Orange and the Volcano Alert Level to Watch. Weakly elevated surface temperatures were identified in several satellite images during 6-7 February, consistent with the presence of a lava dome that began forming in late January.
Geological summary: Beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited, dumbbell-shaped Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano. Cleveland is joined to the rest of Chuginadak Island by a low isthmus. The 1730-m-high Mount Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name for Mount Cleveland, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano. Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998). In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
Piton de la Fournaise, Reunion Island (France)
21.244°S, 55.708°E, Elevation 2632 m
OVPF reported that seismicity and inflation at Piton de la Fournaise significantly increased on 2 January. Based on seismic data, an eruption began at 1940 on 31 January. Visual observations on 1 February confirmed that the active vent was located about 1 km SE of Château Fort and about 2.5 km ENE of Piton de Bert.Lava fountains rose 20-50 m above the 10-m-high vent, and ‘a’a lava flows branched and traveled 750 m. Two other cracks had opened at the beginning of the eruption but were no longer active. Tremor levels decreased in the early hours of the eruption; RSAM values then fluctuated at mid-range, and lava-fountain heights were variable (between 20-50 m). On 2 February two lava fountains at the vent were visible, and lava flows had traveled an additional 500 m E. The vent was 128 m long and about 35 m high at the highest part. The next day RSAM levels were more stable, at a value which was half of what it was at the beginning of the eruption. On 4 February OVPF noted that significant fluctuations of volcanic tremor were detected for more than 24 hours, with intensity levels reaching those observed at the onset of the eruption. Higher levels of seismicity continued through 7 February. Poor weather conditions prevented visual observations during 4-7 February.
Geological summary: The massive Piton de la Fournaise basaltic shield volcano on the French island of Réunion in the western Indian Ocean is one of the world's most active volcanoes. Much of its more than 530,000-year history overlapped with eruptions of the deeply dissected Piton des Neiges shield volcano to the NW. Three calderas formed at about 250,000, 65,000, and less than 5000 years ago by progressive eastward slumping of the volcano. Numerous pyroclastic cones dot the floor of the calderas and their outer flanks. Most historical eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest caldera, which is 8 km wide and breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from fissures on the outer flanks of the caldera. The Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris, monitors this very active volcano.
Takawangha, Andreanof Islands (USA)
51.873°N, 178.006°W, Elevation 1449 m
On 3 February AVO stated that the seismic swarm that began at Takawangha on 23 January continued but at a decreased rate and intensity. The rate of earthquakes peaked at 190 events on 24 January, and since then had steadily declined; 2-8 events per day were recorded from late January to 3 February. Most of the events were located 7-8 km ESE, at shallow depths. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at 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.
Bogoslof, Fox Islands (USA)
53.93°N, 168.03°W, Elevation 150 m
AVO reported that no further emissions were detected at Bogoslof after an explosion at 0520 on 31 January; the Aviation Color Code (ACC) was lowered to Orange and the Volcano Alert Level (VAL) was lowered to Watch the next day. A burst of tremor lasting nine minutes was detected starting at 0457 on 3 February. A second burst, starting at 0533 and lasting 20 minutes, was also detected by infrasound instruments, indicating an explosion. No ash cloud was detected above the meteorological cloud deck in satellite data. An event that began at 1642 produced a small volcanic plume that drifted about 40 km N below an altitude of 7.6 km (25,000 ft) a.s.l. Seismic tremor significantly decreased later that evening. Weakly elevated surface temperatures were observed in two satellite images acquired on 5 February, possibly related to hot deposits from explosive activity the day before.
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.
19.514°N, 103.62°W, Elevation 3850 m
The Washington VAAC reported that on 1 February an ash emission was recorded by the webcam rising from Colima. Weather clouds prevented satellite observations of the event. Based on webcam and satellite images, the Mexico City MWO, and model data, the VAAC noted that during 3-6 February ash plumes rose to altitudes of 5.2-7.6 km (17,000-25,000 ft) a.s.l. and drifted NW, W, SW, and S.
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 and model data, the Darwin VAAC reported that during 1-2 and 5-7 February ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted at least 130 km SE and E.
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
KVERT reported that moderate gas-and-steam emissions possibly containing small amounts of ash continued at Ebeko during 27 January-3 February. Minor ashfall was reported in Severo-Kurilsk (Paramushir Island) about 7 km E on 30 January. 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.
14.473°N, 90.88°W, Elevation 3763 m
In a special report from 2 February, INSIVUMEH noted increased activity at Fuego characterized by explosions occurring every 5-15 minutes. Ash plumes rose as high as 750 m and drifted 15 km W, causing ashfall in areas downwind including Sangre de Cristo and San Pedro Yepocapa. During 2-7 February explosions generated ash plumes that rose 0.4-1.1 km above the crater and drifted at most 12 km NW, W, SW, and S. Incandescent material was ejected 150 m high, and avalanches traveled down the Taniluyá (SW) and Ceniza (SSW) drainages. Ashfall was reported in areas downwind including Sangre de Cristo (8 km WSW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Rochela, and Panimaché I and II (8 km SW). Shock waves from explosions rattled nearby structures.
Geological 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.
Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Elevation 1222 m
During 1-7 February 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.
HVO geologists noted an extensive crack running parallel to the sea cliff about 5-10 m behind the stream of lava entering the ocean at Kamokuna. The crack was 30 cm wide on 28 January and 70 cm wide four days later, on 1 February. In addition, the seaward block bounded by this crack was visibly moving up to 1 cm, and ground shaking could be felt up to several hundred meters away. On 2 February the crack was wider and steaming, and the stream of lava that had been pouring into the ocean from an opening in a lava tube about 20 m above the water was no longer visible (though lava continued to enter the ocean). At about 1255 almost the entire section of the sea cliff that was seaward of the hot crack collapsed. The collapsed block generated a wave that propagated outward from the coast. After the collapse, no lava was visible entering the ocean though a steam plume and spatter from explosions indicated that the entry remained active.
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.
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 2-6 February. Weather clouds sometimes prevented visual 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 27 January-3 February 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 and webcam images, and wind data, the Darwin VAAC reported that during 2-7 February ash plumes from Sinabung rose to altitudes as high as 7.3 km (24,000 ft) a.s.l. and drifted NE, E, SE, and SW.
BNPB reported that each day during 2-7 February there were 8-12 ash-producing events with plumes rising as high as 2 km above the crater and drifting E. Pyroclastic flows traveled as far as 2 km S, SE, and E. BNPB noted that more areas had been designated disaster prone, therefore the number of people needed to be relocated also increased. The Alert Level remained at 4 (on a scale of 1-4), with an exclusion zone of 7 km from the volcano on the SSE sector, and 6 km in the ESE sector, and 4 km in the NNE sector.
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
On 1 February OVSICORI-UNA reported that since 27 January the seismic network at Turrialba recorded variable-amplitude, discontinuous tremor indicative of moving pressurized volcanic fluid. Passive emissions of ash were observed during 1-2 February, rising as high as 500 m above the crater. Ashfall was reported in Desamparados, Calle Blancos, and Tres Ríos, and a sulfur odor was noted in San Pablo Heredia. An eruption at 0900 on 4 February generated an ash plume that rose 300 m and drifted W. Almost continuous ash emissions rose at most 500 above the crater during 4-5 February and drifted WSW. Variable-amplitude tremor continued to be recorded.
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.