Active volcanoes in the world: March 2 - 8, 2016

Active volcanoes in the world: March 2 - 8, 2016

New activity was reported for 9 volcanoes between March 2 and 8, 2016. Ongoing activity was observed at 18 volcanoes. 

New activity/unrest: Aira, Kyushu (Japan)  | Alaid, Kuril Islands (Russia)  | Asosan, Kyushu (Japan)  | Lokon-Empung, Sulawesi (Indonesia)  | Makian, Halmahera (Indonesia)  | Nyiragongo, DR Congo  | Santa Maria, Guatemala  | Tungurahua, Ecuador  | Zhupanovsky, Eastern Kamchatka (Russia).

Ongoing activity: Bagana, Bougainville (Papua New Guinea)  | Chirpoi, Kuril Islands (Russia)  | Colima, Mexico  | Copahue, Central Chile-Argentina border  | Dukono, Halmahera (Indonesia)  | Fuego, Guatemala  | Gamalama, Halmahera (Indonesia)  | Gamkonora, Halmahera (Indonesia)  | Ibu, Halmahera (Indonesia)  | Karymsky, Eastern Kamchatka (Russia)  | Kilauea, Hawaiian Islands (USA)  | Manam, Papua New Guinea  | Masaya, Nicaragua  | Momotombo, Nicaragua  | Nevado del Ruiz, Colombia  | Sheveluch, Central Kamchatka (Russia)  | Sinabung, Indonesia  | Suwanosejima, Ryukyu Islands (Japan).

New activity/unrest

Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m

During 29 February-4 March JMA reported that two explosions from Showa Crater at Aira Caldera’s Sakurajima volcano ejected tephra as far as 500 m. At 0038 on 4 March an explosion at Minamidake summit crater generated an ash plume that rose 1.6 km. The Alert Level remained at 3 (on a 5-level scale).

Geological 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.

Alaid, Kuril Islands (Russia)
50.861°N, 155.565°E, Summit elev. 2285 m

KVERT reported that a gas-and-steam plume containing ash drifted 52 km WSW of Alaid on 4 March. Satellite images had detected an intense thermal anomaly during the previous week. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale).

Geological 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.

Asosan, Kyushu (Japan)
32.884°N, 131.104°E, Summit elev. 1592 m

JMA reported that at 0656 on 4 March an explosion at Asosan’s Nakadake Crater generated a milky-white plume that rose 1 km above the crater rim; white plumes rose 300 m afterwards. The amplitude of volcanic tremor had increased around the time of the eruption, but then had decreased afterwards. Fieldwork confirmed that a small amount of sediment had been ejected from the crater's hot lake, and ash had fallen on the E side of Aso and in Takamori (10 km ESE). The Alert Level remained at 2 (on a scale of 1-5).

Geological summary: The 24-km-wide Asosan caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Nakadake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Nakadake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 CE. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Nakadake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.

Lokon-Empung, Sulawesi (Indonesia)
1.358°N, 124.792°E, Summit elev. 1580 m

Although inclement weather sometimes obscured views of Lokon-Empung's Tompaluan Crater, PVMBG reported that during 5 February-8 March observers at the post in Kakaskasen Tomohon (North Sulawesi, 4 km from the crater) saw white plumes rising as high as 200 m above the crater. Seismicity increased; shallow volcanic earthquakes notably increased on 6 March. Deformation data indicated inflation. The Alert Level was raised to 3 (on a scale of 1-4) on 8 March due to significant increases in deformation and seismic data. Residents and tourists were reminded not to approach the crater within a radius of 2.5 km.

Geological summary: The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2 km apart), has a flat, craterless top. The morphologically younger Empung volcano to the NE has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred. A ridge extending WNW from Lokon includes Tatawiran and Tetempangan peak, 3 km away.

Makian, Halmahera (Indonesia)
0.32°N, 127.4°E, Summit elev. 1357 m

PVMBG reported that seismicity at Makian increased at the beginning of January and was characterized by deep volcanic earthquakes, low-frequency events, and tremor. Tremor amplitude increased at the beginning of March. Gas emissions did not change; weak solfatara emissions continued to rise from the crater floor. The Alert Level was raised to 3 (on a scale of 1-4) on 7 March. Residents and tourists were reminded not to approach the crater within a radius of 1.5 km.

Geological summary: Makian volcano forms a 10-km-wide island near the southern end of a chain of volcanic islands off the west coast of Halmahera and has been the source of infrequent, but violent eruptions that have devastated villages on the island. The large 1.5-km-wide summit crater, containing a small lake on the NE side, gives the peak a flat-topped profile. Two prominent valleys extend to the coast from the summit crater on the north and east sides. Four parasitic cones are found on the western flanks. Eruption have been recorded since about 1550; major eruptions in 1646, 1760-61, 1861-62, 1890, and 1988 caused extensive damage and many fatalities.

Nyiragongo, DR Congo
1.52°S, 29.25°E, Summit elev. 3470 m

The Observatoire volcanologique de Goma reported that activity at Nyiragongo intensified on 28 February. On 1 March scientists observed a second lava lake on the E part of the crater floor.

Geological summary: One of Africa's most notable volcanoes, Nyiragongo contained a lava lake in its deep summit crater that was active for half a century before draining catastrophically through its outer flanks in 1977. In contrast to the low profile of its neighboring shield volcano, Nyamuragira, 3470-m-high Nyiragongo displays the steep slopes of a stratovolcano. Benches in the steep-walled, 1.2-km-wide summit crater mark levels of former lava lakes, which have been observed since the late-19th century. Two older stratovolcanoes, Baruta and Shaheru, are partially overlapped by Nyiragongo on the north and south. About 100 parasitic cones are located primarily along radial fissures south of Shaheru, east of the summit, and along a NE-SW zone extending as far as Lake Kivu. Many cones are buried by voluminous lava flows that extend long distances down the flanks, which is characterized by the eruption of foiditic rocks. The extremely fluid 1977 lava flows caused many fatalities, as did lava flows that inundated portions of the major city of Goma in January 2002.

Santa Maria, Guatemala
14.756°N, 91.552°W, Summit elev. 3772 m

INSIVUMEH reported that on 3 March an explosion from Caliente cone, part of Santa María's Santiaguito lava-dome complex, generated an ash plume that rose 700 m and drifted SE. Ashfall was reported in the ranches of San José and La Quina. Weak avalanches descended the E flank. In a special bulletin posted on 8 March, INSIVUMEH stated that a moderate explosion caused a collapse of part of Caliente cone. A pyroclastic flow descended the NNE flank, and a dense ash plume that covered the entire volcanic complex rose as high as 1.5 km and drifted NNE.

Geological 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.

Tungurahua, Ecuador
1.467°S, 78.442°W, Summit elev. 5023 m

IG reported that moderate-to-high levels of Strombolian activity at Tungurahua continued during 2-8 March. Daily explosions were often accompanied by roaring and sounds resembling gunshots, and often caused local structures to vibrate. Steam-and-ash plumes rose from the crater daily often to heights less than 2.5 km above the crater and drifted NW, WNW, W, and SW; ash plumes rose 5 km on 4 March and to 6 km with a SE drift on 8 March. Ashfall was also reported daily in areas including Chontapamba (W), Pillate (8 km W), Bilbao (8 km W), Chacauco (NW), Juive (NW), Quero (20 km NW), Cusúa (NW), Choglontús (13 km WSW), Pelileo (8 km N), El Manzano (8 km SW), Vazcún (N), and Pondoa (N). Strombolian explosions observed nightly ejected incandescent blocks that rolled as far as 2 km down the flanks.

At 1020 on 4 March an explosion vibrated windows and generated an ash plume that rose 3 km above the crater. A pyroclastic flow traveled 1 km down the Romero drainage, and at 1152 another pyroclastic flow traveled 500 m down Achupashal (NW) drainage. On 6 March another explosion was followed by pyroclastic flows that traveled 1 km down the Achupashal, Rea, Pondoa (N), and Mandur (NW) drainages. Pyroclastic flows on 8 March traveled as far as 2.2 km down the Mandur, Romero, Bilbao, Juive, and Achupashal drainages.

On 5 March lahars descended the ravines of Achupashal, Juive, Pondoa, Mandur, Pingullo, Rea and Chontapamba; lahars in Pingullo and Cusúa led to the closure of the road.

Geological summary: Tungurahua, a steep-sided andesitic-dacitic stratovolcano that towers more than 3 km above its northern base, is one of Ecuador's most active volcanoes. Three major edifices have been sequentially constructed since the mid-Pleistocene over a basement of metamorphic rocks. Tungurahua II was built within the past 14,000 years following the collapse of the initial edifice. Tungurahua II itself collapsed about 3000 years ago and produced a large debris-avalanche deposit and a horseshoe-shaped caldera open to the west, inside which the modern glacier-capped stratovolcano (Tungurahua III) was constructed. Historical eruptions have all originated from the summit crater, accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. Prior to a long-term eruption beginning in 1999 that caused the temporary evacuation of the city of Baños at the foot of the volcano, the last major eruption had occurred from 1916 to 1918, although minor activity continued until 1925.

Zhupanovsky, Eastern Kamchatka (Russia)
53.589°N, 159.15°E, Summit elev. 2899 m

KVERT reported that moderate gas-and-steam activity at Zhupanovsky continued during 26 February-4 March. The Aviation Color Code remained at Orange.

Geological 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.

Ongoing activity

Bagana, Bougainville (Papua New Guinea)
6.137°S, 155.196°E, Summit elev. 1855 m

Based on analyses of satellite imagery and model data, the Darwin VAAC reported that on 3 March a plume from Bagana possibly containing ash rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 110 km NE; ash was not discernible in images and RVO stated that ash was not seen by ground observers. The next day an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 45-55 km NE and E.

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, 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

Based on satellite images, the Tokyo VAAC reported that on 6 March a possible eruption at Chirpoi may have produced an ash plume that rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted E. A subsequent image the next day showed that any ash had dissipated.

Geological 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.

Colima, Mexico
19.514°N, 103.62°W, Summit elev. 3850 m

Based on satellite and webcam images, notices from the Mexico City MWO, and information from Colima Towers, the Washington VAAC reported that on 2, 4, 5, and 7 March ash plumes from Colima rose to altitude of 4.3-5.5 km (14,000-18,000 ft) a.s.l. and drifted NE and SW. A hotspot was detected on 2 March.

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, Summit elev. 2953 m

The Buenos Aires VAAC reported that during 5-7 March a webcam recorded minor stream-and-gas emissions near Copahue’s crater; on 7 March the emissions drifted SE and ESE at altitudes of 3-3.7 km (10,000-12,000 ft) a.s.l.

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, Summit elev. 1229 m

PVMBG reported that during 1 January-7 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.

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.

Fuego, Guatemala
14.473°N, 90.88°W, Summit elev. 3763 m

INSIVUMEH noted that the fourth episode of effusive activity at Fuego for 2016 had begun on 29 February and lasted for about 48 hours. At the beginning of the episode, ash plumes rose as high as 1.3 km and drifted 15 km S and SW, and lava fountains rose 100-150 m above the crater. In a special report on 2 March, INSIVUMEH noted that explosions persisted even though seismicity had declined. Explosions, detected 25 km away, produced ash plumes that rose 2.3 km above the crater and drifted 40 km W and NW. Ash fell in Sangre de Cristo, Morelia, Panimaché I and II, and Yepocapa. A 3-km-long lava flow advanced in the Honda ravine. Later that day, at 1930, INSIVUMEH stated that the effusive episode had ended. Weak explosions generated ash plumes that rose 750 m and drifted 10 km WNW. During 3 and 5-6 March explosions continued, producing ash plumes that rose as high as 550 m and drifted 8-10 km W, SW, and SE.

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.

Gamalama, Halmahera (Indonesia)
0.8°N, 127.33°E, Summit elev. 1715 m

PVMBG reported that During 1 January-6 March seismicity at Gamalama fluctuated but decreased overall; shallow volcanic earthquakes and signals indicating emissions appeared on 3 March and a series of deep volcanic earthquakes were detected on 6 March. The Alert Level remained at 2 (on a scale of 1-4); visitors and residents were warned not to approach the crater within a 1.5-km radius.

Geological summary: Gamalama is a near-conical stratovolcano that comprises the entire island of Ternate off the western coast of Halmahera, and is one of Indonesia's most active volcanoes. The island was a major regional center in the Portuguese and Dutch spice trade for several centuries, which contributed to the thorough documentation of Gamalama's historical activity. Three cones, progressively younger to the north, form the summit. Several maars and vents define a rift zone, parallel to the Halmahera island arc, that cuts the volcano. Eruptions, recorded frequently since the 16th century, typically originated from the summit craters, although flank eruptions have occurred in 1763, 1770, 1775, and 1962-63.

Gamkonora, Halmahera (Indonesia)
1.38°N, 127.53°E, Summit elev. 1635 m

PVMBG reported that observers at the Gamkonora observation post in Gamsungi (6 km NW), West Halmahera, reported that during 1 January-6 March diffuse white plumes rose up to 150 m above the crater rim, although weather conditions often obscured views. RSAM values fluctuated; higher values during mid-January through February were due to increased tremor and tornillo-type earthquakes. The Alert Level remained at 2 (on a scale of 1-4). Residents and tourists were asked not to venture near the crater within a radius of 1.5 km.

Geological summary: The shifting of eruption centers on Gamkonora, the highest peak of Halmahera, has produced an elongated series of summit craters along a N-S trending rift. Youthful-looking lava flows originate near the cones of Gunung Alon and Popolojo, south of Gamkonora. Since its first recorded eruption in the 16th century, typical activity has been small-to-moderate explosive eruptions. Its largest historical eruption, in 1673, was accompanied by tsunamis that inundated villages.

Ibu, Halmahera (Indonesia)
1.488°N, 127.63°E, Summit elev. 1325 m

PVMBG reported that during 1 January-7 March white-to-gray plumes rose as high as 500 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.

Geological 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 explosive activity at Karymsky continued during 26 February-4 March. Daily satellite images detected a thermal anomaly over the volcano and fresh ash deposits. The Aviation Color Code remained at Orange.

Geological 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 2-8 March. The lava lake continued to circulate and spatter in the Overlook vent. Webcams recorded multiple incandescent outgassing vents within Pu'u 'O'o Crater and high on the northeast rim. At 0200 on 2 March a small cone on the E side of the crater briefly produced spatter, and then at 0815 a vigorous lava flow erupted from a W vent. During 3-4 and 6-7 March minor amounts of lava intermittently flowed from S vents. The June 27th NE-trending lava flow continued to be active within 6 km NE of Pu'u 'O'o Crater, burning some areas of forest.

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 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.

Manam, Papua New Guinea
4.08°S, 145.037°E, Summit elev. 1807 m

Based on observations of satellite imagery and pilot observations, the Darwin VAAC reported that on 4 March an ash plume from Manam rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted over 90 km SE.

Geological summary: The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys" channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.

Masaya, Nicaragua
11.984°N, 86.161°W, Summit elev. 635 m

INETER reported that on 3 March the lava lake on the SW floor of Masaya's Santiago crater was very active. Volcanic tremor remained high and RSAM values were at high to very high levels.

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.

Momotombo, Nicaragua
12.422°N, 86.54°W, Summit elev. 1297 m

During 2-3 March INETER reported that 53 small explosions at Momotombo generated low-energy gas plumes that rose 300 m above the crater. On 3 March some of the explosions produced ash plumes that drifted W and SW. RSAM values were at low to moderate levels. SINAPRED reported that during 5-6 March there were 78 explosions for a total of 279 explosions detected since 1 December 2015. One of the most significant explosions occurred on 6 March. The next day gas-and-ash plumes rose as high as 1 km above the crater.

Geological 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

SGC reported that an episode of volcanic tremor at Nevado del Ruiz began at 0923 on 3 March and was associated with an ash plume that rose 3 km above the crater. Based on satellite and webcam images, the Washington VAAC stated that an ash plume rose to an altitude of 9.1 km (30,000 ft) a.s.l. (about 800 m higher than the SGC estimate) and drifted NW. Later that day satellite images detected an ash plume drifting 40 km W. According to the VAAC, the Bogota MWO reported that on 7 March an ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted WNW.

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, Summit elev. 3283 m

KVERT reported that during 26 February-4 March lava-dome extrusion onto Sheveluch’s N flank was accompanied by fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images detected a daily and intense thermal anomaly over the dome. A gas-and-steam plume with minor amounts of ash drifted almost 55 km SE. 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.

Sinabung, Indonesia
3.17°N, 98.392°E, Summit elev. 2460 m

Based on satellite images, ground reports, and information from PVMBG, the Darwin VAAC reported that during 2 and 5-6 March ash plumes from Sinabung rose to altitudes of 3.6-4.3 km (12,000-14,000 ft) a.s.l. and drifted as far as 55 km SE, SW, and W.

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, 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.

Suwanosejima, Ryukyu Islands (Japan)
29.638°N, 129.714°E, Summit elev. 796 m

Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 2-3 and 8 March explosions at Suwanosejima generated ash plumes that rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and sometimes drifted SE. Explosions were also detected on 5 and 7 March.

Geological 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.

Source: GVP

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