Active volcanoes in the world: October 1 - 7, 2014

Active volcanoes in the world: October 1 - 7, 2014

New activity/unrest was observed at 7 volcanoes from October 1 - 7, 2014. Ongoing activity was reported for 10 volcanoes.

New activity/unrest: Bardarbunga, Iceland  | Copahue, Central Chile-Argentina border  | Lewotobi, Flores Island (Indonesia)  | Mayon, Luzon (Philippines)  | Ontakesan, Honshu (Japan)  | Sheveluch, Central Kamchatka (Russia)  | Sinabung, Indonesia

Ongoing activity: Aira, Kyushu (Japan)  | Asosan, Kyushu (Japan)  | Dukono, Halmahera (Indonesia)  | Karymsky, Eastern Kamchatka (Russia)  | Kilauea, Hawaiian Islands (USA)  | Kuchinoerabujima, Ryukyu Islands (Japan)  | Shishaldin, Fox Islands (USA)  | Stromboli, Aeolian Islands (Italy)  | Tungurahua, Ecuador  | Zhupanovsky, Eastern Kamchatka (Russia)

New activity/unrest

Bardarbunga, Iceland
64.63°N, 17.53°W, Summit elev. 2009 m

During 1-7 October, IMO maintained Aviation Colour Code Orange due to continued activity at Bárdarbunga’s Holuhraun eruptive fissure. Subsidence of the Bárdarbunga caldera continued. Seismic activity at the N part of the dyke and around the vents declined, although the lava field continued to grow and lava production continued at the same output. On 5 October a new lava front at the S edge of the main lava flow advanced E.

Geologic summary: The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions.

Copahue, Central Chile-Argentina border
37.856°S, 71.183°W, Summit elev. 2953 m

The Buenos Aires VAAC reported that during 6-7 October diffuse steam-and-gas emissions from Copahue detected in satellite images contained a small amount of ash. The webcam showed that the emission source was near the summit.

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.

Lewotobi, Flores Island (Indonesia)
8.542°S, 122.775°E, Summit elev. 1703 m

Based on analysis of satellite images and wind data, the Darwin VAAC reported that on 6 October a narrow, low-level ash plume from Lewotobi rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 185 km WNW.

Geologic summary: The Lewotobi "husband and wife" twin volcano (also known as Lewetobi) in eastern Flores Island is composed of the Lewotobi Lakilaki and Lewotobi Perempuan stratovolcanoes. Their summits are less than 2 km apart along a NW-SE line. The conical 1584-m-high Lewotobi Lakilaki has been frequently active during the 19th and 20th centuries, while the taller and broader 1703-m-high Lewotobi Perempuan has erupted only twice in historical time. Small lava domes have grown during the 20th century in the crescentic summit craters of both volcanoes, which are open to the north. A prominent flank cone, Iliwokar, occurs on the east flank of Lewotobi Perampuan.

Mayon, Luzon (Philippines)
13.257°N, 123.685°E, Summit elev. 2462 m

PHIVOLCS reported that during 1-7 October the seismic network at Mayon recorded 0-7 rockfall events per day. White steam plumes drifted SSE, ESE, and NW. Alert Level remained at 3 (on a 0-5 scale).

Geologic summary: Beautifully symmetrical Mayon volcano, which rises to 2462 m above the Albay Gulf, is the Philippines' most active volcano. The structurally simple volcano has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions at this basaltic-andesitic volcano date back to 1616 and range from strombolian to basaltic plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often devastated populated lowland areas. Mayon's most violent eruption, in 1814, killed more than 1200 people and devastated several towns.

Ontakesan, Honshu (Japan)
35.893°N, 137.48°E, Summit elev. 3067 m

JMA reported that ash emissions from Ontakesan likely continued during 1-7 October. The plume height could not be determined due to poor visibility although on 7 October observers noted that the plume rose 300 m above the crater rim and drifted E. Seismic levels fluctuated; tremor continued to be detected. A news article from 8 October noted that the number of people killed in the 27 September eruption had reached 55; nine were still missing. The Alert Level remained at 3 (on a scale of 1-5).

Geologic summary: The massive Ontakesan stratovolcano, the second highest volcano in Japan, lies at the southern end of the Northern Japan Alps. Ascending this volcano is one of the major objects of religious pilgrimage in central Japan. It is constructed within a largely buried 4 x 5 km caldera and occupies the southern end of the Norikura volcanic zone, which extends northward to Yakedake volcano. The older volcanic complex consisted of at least four major stratovolcanoes constructed from about 680,000 to about 420,000 years ago, after which Ontakesan was inactive for more than 300,000 years. The broad, elongated summit of the younger edifice is cut by a series of small explosion craters along a NNE-trending line. Several phreatic eruptions post-date the roughly 7300-year-old Akahoya tephra from Kikai caldera. The first historical eruption took place in 1979. A non-eruptive landslide in 1984 produced a debris avalanche and lahar that swept down valleys south and east of the volcano. Very minor phreatic activity caused a dusting of ash near the summit in 1991 and 2007. A significant phreatic explosion in September 2014, when the mountain had many hikers, resulted in more than 30 fatalities.

Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Summit elev. 3283 m

KVERT reported that during 26 September-3 October lava-dome extrusion onto Sheveluch’s N flank was accompanied by ash explosions, incandescence, hot avalanches, and fumarolic activity. Satellite images detected a thermal anomaly over the dome during 27-29 September and 2 October. Two explosions on 2 October generated ash plumes that rose to an altitude of 4 km (13,100 ft) a.s.l. and drifted 220 km WSW. 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.

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

Based on reports from PVMBG, BNPB reported four eruptions from Sinabung on 5 October. The first one occurred at 0146, and produced a pyroclastic flow that traveled 4.5 km S and an ash plume that rose 2 km. The next three events, at 0638, 0736, and 0753, all generated pyroclastic flows that traveled 2.5-4.5 km S. The fourth event also produced an ash plume that rose 3 km. A news article stated that pyroclastic flows from a fifth event at 0900 were smaller, but again traveled 4.5 km after a sixth event at 1200.

According to the Darwin VAAC a low-level eruption recorded by the PVMBG webcam generated a pyroclastic flow on 6 October; some of the ash rose higher and drifted E. The Jakarta MWO noted that an ash plume rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted S on 7 October. Cloud cover prevented satellite observations. A news article posted on 8 October noted that eruptions in the previous four days caused some evacuations.

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 of Sinabung 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.

Ongoing activity

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

JMA reported that five explosions from Showa Crater at Aira Caldera’s Sakurajima volcano ejected tephra as far as 1,300 m from the crater during 29 September-3 October. Incandescence from Showa Crater was visible at night during 2-3 October. The Alert Level remained at 3 (on a scale of 1-5). The Tokyo VAAC reported that during 2-7 October plumes rose to altitudes of 1.2-3.7 km (4,000-12,000 ft) a.s.l. and drifted in multiple directions. On 2 October a pilot observed an ash plume that rose to an altitude of 3 km (10,000 ft) a.s.l.

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.

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

JMA reported that Alert Level 2 at Asosan continued during 29 September-3 October. A persistent white plume rose 600 m above the crater. Incandescence from Nakadake Crater was visible during 29-30 September. The Alert Level remained at 2 (on a scale of 1-5).

Geologic 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.

Dukono, Halmahera (Indonesia)
1.68°N, 127.88°E, Summit elev. 1335 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 1 October an ash plume from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 45 km NE. During 5-7 October ash plumes rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55-110 km E and ENE.

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.

Karymsky, Eastern Kamchatka (Russia)
54.049°N, 159.443°E, Summit elev. 1513 m

KVERT reported that a four-minute long explosion from Karymsky was detected by the seismic network beginning at 1115 on 4 October. Pilots observed an ash plume that rose to an altitude of 3 km (10,000 ft) a.s.l. The Aviation Color Code remained at Yellow.

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

During 1-7 October HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Gas emissions remained elevated. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas; smaller particles may have been dropped several kilometers away. At Pu'u 'O'o Crater, glow emanated from several outgassing openings in the crater floor.

The 27 June NE-trending lava flow remained active; flows that had broken out upslope from the leading but stalled front had overtaken that front by 1 October. By 6 October the115-m-wide flow was advancing at a rate of about 120 m/day and was 1.2 km upslope from Apa`a Street. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Warning.

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.

Kuchinoerabujima, Ryukyu Islands (Japan)
30.443°N, 130.217°E, Summit elev. 657 m

JMA reported that no eruptions occurred from Kuchinoerabujima during 29 September-3 October. White plumes rose 600 m above the crater. Low-level seismicity continued and tremor was absent. The Alert Level remained at 3 (on a scale of 1-5).

Geologic summary: A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyus, 15 km west of Yakushima. Furutake, Shintake, and Noike were erupted from south to north, respectively, to form a composite cone that is parallel to the trend of the Ryukyu Islands. The highest peak, Furutake, reaches only 657 m above sea level. The youngest cone, 640-m-high Shintake, was formed after the NW side of Furutake was breached by an explosion. All historical eruptions have occurred from Shintake, although a lava flow from the S flank of Furutake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shintake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions.

Shishaldin, Fox Islands (USA)
54.756°N, 163.97°W, Summit elev. 2857 m

AVO reported that seismicity at Shishaldin indicated that a low-level eruption likely continued during 1-7 October. Strongly elevated surface temperatures at the summit were periodically detected in satellite images; cloud cover sometimes obscured satellite and webcam observations. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Geologic summary: The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. There are over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.

Stromboli, Aeolian Islands (Italy)
38.789°N, 15.213°E, Summit elev. 924 m

Based on a SIGMET notice, the Toulouse VAAC reported low-level ash from Stromboli on 30 September.

Geologic summary: Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small, 924-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period from about 13,000 to 5000 years ago was followed by formation of the modern Stromboli edifice. The active summit vents are located at the head of the Sciara del Fuoco, a prominent horseshoe-shaped scarp formed about 5000 years ago as a result of the most recent of a series of slope failures that extend to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli for more than a millennium.

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

IG reported that during 1-7 October visual observations of Tungurahua were limited due to cloud cover. A small ash emission drifted W on 1 October and a plume with low ash content rose 1 km on 6 October. Ashfall was reported in El Manzano (8 km SW) and Choglontus (SW) on 1 October, in El Manzano, Chontillo, and Ambato (31 km N) on 3 October, and in Pillate (8 km W) on 6 October.

Geologic 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 an explosive eruption at Zhupanovsky continued during 26 September-3 October. Satellite images detected a thermal anomaly on 27 September, and ash plumes that rose to altitudes of 4-4.5 km (13,000-14,800 ft) a.s.l. and drifted 205 km E on 28 September. 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.

Source: GVP

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