New activity/unrest was reported for 5 volcanoes between March 23 and 29, 2016. During the same period, ongoing activity was observed at 21 volcanoes.
New activity/unrest: Alaid, Kuril Islands (Russia) | Chikurachki, Paramushir Island (Russia) | Kanlaon, Philippines | Pavlof, United States | Sangay, Ecuador.
Ongoing activity: Aira, Kyushu (Japan) | Bagana, Bougainville (Papua New Guinea) | Chirpoi, Kuril Islands (Russia) | Colima, Mexico | Copahue, Central Chile-Argentina border | Dukono, Halmahera (Indonesia) | Fuego, Guatemala | Ibu, Halmahera (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Masaya, Nicaragua | Momotombo, Nicaragua | Nevado del Ruiz, Colombia | Popocatepetl, Mexico | Santa Maria, Guatemala | Sheveluch, Central Kamchatka (Russia) | Sinabung, Indonesia | Soputan, Sulawesi (Indonesia) | Suwanosejima, Ryukyu Islands (Japan) | Telica, Nicaragua | Zhupanovsky, Eastern Kamchatka (Russia).
Alaid, Kuril Islands (Russia)
50.861°N, 155.565°E, Summit elev. 2285 m
KVERT reported that moderate activity at Alaid continued during 18-25 March. Satellite images showed an intense thermal anomaly over the volcano during 18 and 21-25 March; cloud cover obscured views during 19-20 March. A gas-and-steam plume containing minor amounts of ash drifted about 90 km NW on 22 March. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Geologic summary: The highest and northernmost volcano of the Kuril Islands, 2285-m-high Alaid is a symmetrical stratovolcano when viewed from the north, but has a 1.5-km-wide summit crater that is breached widely to the south. Alaid is the northernmost of a chain of volcanoes constructed west of the main Kuril archipelago and rises 3000 m from the floor of the Sea of Okhotsk. Numerous pyroclastic cones dot the lower flanks of basaltic to basaltic-andesite Alaid volcano, particularly on the NW and SE sides, including an offshore cone formed during the 1933-34 eruption. Strong explosive eruptions have occurred from the summit crater beginning in the 18th century. Reports of eruptions in 1770, 1789, 1821, 1829, 1843, 1848, and 1858 were considered incorrect by Gorshkov (1970). Explosive eruptions in 1790 and 1981 were among the largest in the Kuril Islands during historical time.
Chikurachki, Paramushir Island (Russia)
50.324°N, 155.461°E, Summit elev. 1781 m
KVERT reported that at 1259 on 29 March an ash plume from Chikurachki was observed in satellite images rising to an altitude of 3 km (10,000 ft) a.s.l. and drifting about 50 km NE. The Aviation Color Code was raised to Orange. By 0852 on 30 March the ash plume was drifting 87 km S. Chikurachki is not monitored with seismic instruments but is observed using ground-based methods and satellite images.
Geologic summary: Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is actually a relatively small cone constructed on a high Pleistocene volcanic edifice. Oxidized basaltic-to-andesitic scoria deposits covering the upper part of the young cone give it a distinctive red color. Frequent basaltic plinian eruptions have occurred during the Holocene. Lava flows from 1781-m-high Chikurachki reached the sea and form capes on the NW coast; several young lava flows also emerge from beneath the scoria blanket on the eastern flank. The Tatarinov group of six volcanic centers is located immediately to the south of Chikurachki, and the Lomonosov cinder cone group, the source of an early Holocene lava flow that reached the saddle between it and Fuss Peak to the west, lies at the southern end of the N-S-trending Chikurachki-Tatarinov complex. In contrast to the frequently active Chikurachki, the Tatarinov volcanoes are extensively modified by erosion and have a more complex structure. Tephrochronology gives evidence of only one eruption in historical time from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959.
10.412°N, 123.132°E, Summit elev. 2435 m
PHIVOLCS reported that at 1820 on 29 March the seismic network at Kanlaon detected an explosion that lasted about 12 minutes. The event was accompanied by a booming sound heard in communities to the W, including Ara-al, Yubo, La Carlota City (14 km W), and Canlaon City (8 km ESE) in Negros Occidental. Observers to the SE reported an ash plume that rose 1.5 km above the crater; minor amounts of ash fell in areas downwind. Incandescent ejecta caused a small bushfire on the upper flank. A 25-second-long explosion was detected at 1918. The Alert Level remained at 1 (on a scale of 0-5).
Geologic summary: Kanlaon volcano (also spelled Canlaon), the most active of the central Philippines, forms the highest point on the island of Negros. The massive 2435-m-high andesitic stratovolcano is dotted with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km to the SW from Kanlaon. The summit of Kanlaon contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller, but higher, historically active vent, Lugud crater, to the south. Historical eruptions from Kanlaon, recorded since 1866, have typically consisted of phreatic explosions of small-to-moderate size that produce minor ashfalls near the volcano.
Pavlof, United States
55.417°N, 161.894°W, Summit elev. 2493 m
AVO reported that seismicity at Pavlof began to increase at about 1553 on 27 March, characterized by a quick onset of continuous tremor. An ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and by 1618 was drifting N. AVO raised the Aviation Color Code to Red and the Volcano Alert Level to Warning. During the night lava fountaining from the summit crater was observed by mariners, pilots, and residents of Cold Bay (60 km SW). Lahars likely descended the flanks. Tremor levels remained high on 28 March. Lightning in the ash plume was detected in the morning, and infrasound data from a sensor network located in Dillingham (650 km away) also indicated sustained ash emissions. At 0700 a continuous ash plume was evident in satellite images drifting more than 650 km NE. A SIGMET issued by the National Weather Service (NWS) Alaska Aviation Weather Unit indicated that the maximum ash-cloud altitude was 11 km (37,000 ft) a.s.l. Strongly elevated surface temperatures suggested the presence of surficial lava flows.
The intensity of the eruption significantly declined at 1230 on 28 March; seismicity and infrasound signals decreased to low levels. AVO lowered the Aviation Color Code to Orange and the Volcano Alert Level to Watch. Seismic tremor was slightly above background levels. Ash emissions decreased through the night and were barely visible in a satellite image acquired at 0625 on 29 March. Remnant ash continued to drift over Bristol Bay and areas of interior Alaska. The webcam recorded intermittent, low-level ash plumes rising as high as 4.6 km (15,000 ft) a.s.l.
Geologic summary: The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.
2.005°S, 78.341°W, Summit elev. 5286 m
Based on notices from the Guayaquil MWO, the Washington VAAC reported that on 25 March an ash plume from Sangay rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted W. On 27 March a pilot observed an ash plume rising to an altitude of 7.6 km (25,000 ft) a.s.l. and drifting W. The next day an ash plume rose to an altitude of 6.4 km (21,000 ft) a.s.l. and drifted WSW. Cloud cover prevented satellite observations of the volcano on all three days.
Geologic summary: The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. The dominantly andesitic volcano has been in frequent eruption for the past several centuries. The steep-sided, 5230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of a historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex.
Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m
JMA reported that an explosion at 0159 on 24 March from Showa Crater at Aira Caldera’s Sakurajima volcano ejected tephra as far as 800 m, and generated an ash plume that rose 2.1 km above the crater rim. At 0825 on 25 March an explosion at Minamidake summit crater produced an ash plume that rose 2 km above the crater rim. Two explosions at Showa Crater, detected at 0248 and 1044 on 26 March, sent ash plumes as high as 2.7 km and ejected tephra 1.3 km away onto the flanks. Tephra 8 mm in diameter fell 4 km away. Ash from an explosion at Minamidake rose as high as 2 km. The Alert Level remained at 3 (on a 5-level scale).
Geologic 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.
Bagana, Bougainville (Papua New Guinea)
6.137°S, 155.196°E, Summit elev. 1855 m
Based on analyses of satellite imagery and wind-model data, the Darwin VAAC reported that on 24 March ash plumes from Bagana rose to an altitude of 3.6 km (12,000 ft) a.s.l. and drifted 45-55 km NE and ENE.
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, roughly 1850-m-high 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 volcano's flanks on all sides. Satellite thermal measurements indicate a continuous eruption from before February 2000 through at least late August 2014.
Chirpoi, Kuril Islands (Russia)
46.525°N, 150.875°E, Summit elev. 742 m
SVERT reported that satellite images detected a thermal anomaly over Snow, a volcano of Chirpoi, during 21-25 and 27 March. Steam-and-gas emissions were observed on 24 March. The Aviation Color Code remained at Yellow.
Geologic summary: Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.
19.514°N, 103.62°W, Summit elev. 3850 m
Based on satellite and webcam images, the Washington VAAC reported that during 24 and 27-29 March ash plumes from Colima rose to altitude of 4-6.1 km (13,000-20,000 ft) a.s.l. and drifted NE.
Geologic 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, Summit elev. 2953 m
The Buenos Aires VAAC reported that during 23-26 March webcam and satellite images detected steam-and-ash emissions rising above Copahue’s crater to altitudes of 3-3.3 km (10,000-11,000 ft) a.s.l. and drifting NE, SE, and S.
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.
Dukono, Halmahera (Indonesia)
1.693°N, 127.894°E, Summit elev. 1229 m
PVMBG reported that during 7-22 March white-and-gray plumes rose as high as 1.2 km above the rim of Dukono's Malupang Warirang crater, and were accompanied by roaring heard at the Dukono observation post 11 km away. The weather conditions were generally not windy so ash was deposited around the crater area. Seismicity fluctuated at high levels, but decreased overall compared the end of 2015. The Alert Level remained at 2 (on a scale of 1-4). Residents and tourists were advised not to approach the crater within a radius of 2 km.
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 23-29 March ash plumes rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 35-110 km E, SE, S, and SW.
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.
14.473°N, 90.88°W, Summit elev. 3763 m
INSIVUMEH reported that during 24-25 and 27-29 March explosions at Fuego generated ash plumes that rose 550-950 m above the crater and drifted 6-12 km SE, S, SW, and W. Incandescent material was ejected 200 m high on 25 March, producing avalanches within the crater and down the Trinidad (S), Ceniza (SSW), and Taniluyá (SW) drainages. On 29 March ashfall was reported Sangre de Cristo (8 km WSW) and Panimaché I and II (8 km 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.
Ibu, Halmahera (Indonesia)
1.488°N, 127.63°E, Summit elev. 1325 m
PVMBG reported that during 7-22 March gray-to-gray-black plumes rose as high as 700 m above Ibu’s summit crater, although inclement weather often prevented visual observations. Seismicity was dominated by signals indicating surface or near-surface activity, and the continued growth of the lava dome in the N part of the crater. The Alert Level remained at 2 (on a scale of 1-4). The public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.
Geologic summary: The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley. A large parasitic cone is located ENE of the summit. A smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. Only a few eruptions have been recorded in historical time, the first a small explosive eruption from the summit crater in 1911. An eruption producing a lava dome that eventually covered much of the floor of the inner summit crater began in December 1998.
Karymsky, Eastern Kamchatka (Russia)
54.049°N, 159.443°E, Summit elev. 1513 m
KVERT reported that moderate activity at Karymsky continued during 18-25 March. The Aviation Color Code remained at Orange.
Geologic summary: Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.
Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Summit elev. 1222 m
HVO reported that seismicity beneath Kilauea's summit, upper East Rift Zone, and Southwest Rift Zone was at background levels during 23-29 March. The lava lake continued to circulate and spatter in the Overlook vent. Webcams recorded outgassing from multiple spatter cones on the Pu'u 'O'o Crater floor. A small lava flow broke out from a spatter cone on the NE side of the crater floor on 24 March and again the next evening. The June 27th NE-trending lava flow continued to be active within 7.6 km NE of Pu'u 'O'o Crater.
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 of Kilauea 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.
11.984°N, 86.161°W, Summit elev. 635 m
According to a SINAPRED report on 28 March INETER noted that lava-lake activity at Masaya's Santiago crater was intense and the craters continued to gradually widen. Emissions were at low levels.
Geologic 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.
12.422°N, 86.54°W, Summit elev. 1297 m
On 28 March SINAPRED reported that 38 explosions were detected at Momotombo over a period of 24 hours, which ejected gas-and-ash plumes and incandescent tephra. The strongest event occurred at 1140 on 27 March and generated a plume that rose 1 km.
Geologic summary: Momotombo is a young, 1297-m-high stratovolcano that rises prominently above the NW shore of Lake Managua, forming one of Nicaragua's most familiar landmarks. Momotombo began growing about 4500 years ago at the SE end of the Marrabios Range and consists of a somma from an older edifice that is surmounted by a symmetrical younger cone with a 150 x 250 m wide summit crater. Young lava flows from Momotombo have flowed down the NW flank into the 4-km-wide Monte Galán caldera. The youthful cone of Momotombito forms a 391-m-high island offshore in Lake Managua. Momotombo has a long record of strombolian eruptions, punctuated by occasional larger explosive activity. The latest eruption, in 1905, produced a lava flow that traveled from the summit to the lower NE base. A small black plume was seen above the crater after an April 10, 1996 earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the southern flank of the volcano.
Nevado del Ruiz, Colombia
4.892°N, 75.324°W, Summit elev. 5279 m
Based on an ASHTAM (a special Notice to Airmen for airborne ash), the Washington VAAC reported a possible emission from Nevado del Ruiz on 28 March. Ash was not identified in satellite images, though a thermal anomaly was detected. A period of increased seismicity was detected the next day, and observers reported another possible ash emission.
Geologic 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.
19.023°N, 98.622°W, Summit elev. 5426 m
CENAPRED reported that during 22-29 March the seismic network at Popocatépetl recorded 6-60 daily emissions that sometimes contained ash; 127 were detected on 28 March. Crater incandescence was observed on most nights. At 1052 on 24 March an ash plume rose 1.6 km above the crater and drifted NE. At 0026 the next morning a low-intensity explosion generated an ash plume that rose 500 m and drifted NE. Incandescent tephra was ejected as far as 400 m onto the N flank. Explosions during 27-29 March generated plumes that rose as high as 1.5 km. The Alert Level remained at Yellow, Phase Two.
Geologic summary: Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major plinian eruptions, the most recent of which took place about 800 CE, have occurred from Popocatépetl since the mid Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since precolumbian time.
Santa Maria, Guatemala
14.756°N, 91.552°W, Summit elev. 3772 m
INSIVUMEH reported that during 24-25 and 27-29 March explosions from Caliente cone, part of Santa María's Santiaguito lava-dome complex, generated ash plumes that rose 800-900 m and drifted SW. Weak avalanches descended the E and SW flanks of the dome. On 25 March ashfall was reported in San Marcos (10 km SW) and Palajunoj (18 km SSW).
Geologic summary: Symmetrical, forest-covered Santa María volcano is one of the most prominent of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The 3772-m-high stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank and was formed during a catastrophic eruption in 1902. The renowned plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, the most recent of which is Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.
Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Summit elev. 3283 m
KVERT reported that during 18-25 March lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images detected an intense thermal anomaly over the dome almost every day; cloud cover obscured views of the volcano during 20-21 March. An ash plume drifted 38 km N on 23 March. 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.
3.17°N, 98.392°E, Summit elev. 2460 m
Based on satellite images and information from PVMBG, the Darwin VAAC reported that during 23-24 and 28-29 March ash plumes from Sinabung rose to altitudes of 3.9-5.5 km (13,000-18,000 ft) a.s.l. and drifted as far as 55 km NW, W, and SW. A low-level ash plume was identified by PVMBG on 27 March.
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, 2460-m-high andesitic-to-dacitic volcano 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.
Soputan, Sulawesi (Indonesia)
1.112°N, 124.737°E, Summit elev. 1785 m
PVMBG reported that during 21-28 March diffuse white plumes from Soputan rose as high as 100 m above the crater and drifted E. Seismicity was dominated by signals indicating avalanches and emissions; shallow volcanic earthquakes were detected on 21 March. The Alert Level remained at 3 (on a scale of 1-4); residents and tourists were advised not to approach the craters within a radius of 6.5 km.
Geologic summary: The Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano rises to 1784 m and is located SW of Riendengan-Sempu, which some workers have included with Soputan and Manimporok (3.5 km ESE) as a volcanic complex. It was constructed at the southern end of a SSW-NNE trending line of vents. During historical time the locus of eruptions has included both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.
Suwanosejima, Ryukyu Islands (Japan)
29.638°N, 129.714°E, Summit elev. 796 m
Based on JMA notices and satellite data, the Tokyo VAAC reported that during 21, 23-24, and 26 March explosions at Suwanosejima generated ash plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted N, W, and SE. Ash emissions continued on 27 March.
Geologic summary: The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.
12.602°N, 86.845°W, Summit elev. 1061 m
In a 28 March report, SINAPRED noted that incandescence from Telica’s crater continued to be observed, and reminded people to stay away from the crater.
Geologic summary: Telica, one of Nicaragua's most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of 1061-m-high Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately SE of Telica, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby.
Zhupanovsky, Eastern Kamchatka (Russia)
53.589°N, 159.15°E, Summit elev. 2899 m
KVERT reported that moderate activity at Zhupanovsky continued during 18-25 March. According to KVERT, the Tokyo VAAC noted that an explosion generated an ash plume that rose to an altitude of 8 km (26,200 ft) a.s.l. at 0120 on 25 March. An 8 x 10 km ash cloud observed in satellite images drifted about 135 km NW at altitudes of 3.5-4 km (11,500-13,100 ft) a.s.l. that same day. The Aviation Color Code remained at Orange.
Geologic summary: The Zhupanovsky volcanic massif consists of four overlapping stratovolcanoes along a WNW-trending ridge. The elongated volcanic complex was constructed within a Pliocene-early Pleistocene caldera whose rim is exposed only on the eastern side. Three of the stratovolcanoes were built during the Pleistocene, the fourth is Holocene in age and was the source of all of Zhupanovsky's historical eruptions. An early Holocene stage of frequent moderate and weak eruptions from 7000 to 5000 years before present (BP) was succeeded by a period of infrequent larger eruptions that produced pyroclastic flows. The last major eruption took place about 800-900 years BP. Historical eruptions have consisted of relatively minor explosions from the third cone.