New activity/unrest was observed at 9 volcanoes from October 15 - 21, 2014. Ongoing activity was reported also for 9 volcanoes.
New activity/unrest: Cerro Negro de Mayasquer, Colombia-Ecuador | Copahue, Central Chile-Argentina border | Etna, Sicily (Italy) | Karangetang [Api Siau], Siau Island (Indonesia) | Mayon, Luzon (Philippines) | Ontakesan, Honshu (Japan) | Poas, Costarica | Popocatepetl, Mexico | Sinabung, Indonesia
Ongoing activity: Aira, Kyushu (Japan) | Bardarbunga, Iceland | Chirpoi, Kuril Islands (Russia) | Dukono, Halmahera (Indonesia) | Kilauea, Hawaiian Islands (USA) | Sheveluch, Central Kamchatka (Russia) | Shishaldin, Fox Islands (USA) | Stromboli, Aeolian Islands (Italy) | Zhupanovsky, Eastern Kamchatka (Russia)
Cerro Negro de Mayasquer, Colombia-Ecuador
0.828°N, 77.964°W, Elevation 4445 m
On 20 October Servicio Geológico Colombiano (SGC) reported that a M 5.8 earthquake, the largest to date, occurred in the vicinity of the Cerro Negro de Mayasquer and Chiles volcanoes at a depth of less than 10 km. The event was felt to the N in Pasto (Colombia) and to the S in Quito (Ecuador). On 21 October SGC raised the Alert Level for the volcanic complex to Orange (level 3 of 4) noting that a seismic swarm characterized by 4,300 earthquakes was detected in an 18-hour period. Hypocenters were located 1-4 km SW of Chiles volcano at depths of 3-5 km and local magnitudes between M 0.2 and 4.5. Inhabitants felt 11 of the events. On 22 October a report noted that the total number of earthquakes recorded on 21 October reached 7,717, which was the largest number of earthquakes recorded on one day since the installation of a local seismic network in November 2013. Several swarms have occurred in the area since February 2013.
Geologic summary: Cerro Negro de Mayasquer, astride the Colombia-Ecuador border, is a stratovolcano with a caldera open to the west. Andesitic and dacitic lava flows are of possible Holocene age (Hall 1992, pers. comm.). Solfataras are found on the shore of a small crater lake. An historical eruption reported in 1936 may have been from Reventador (Catalog of Active Volcanoes of the World). The higher, glacier-covered summit of the Pleistocene Chiles stratovolcano lies only 3 km SE. Chiles last erupted about 160,000 years ago, but has hot springs and an active hydrothermal system at its eastern flank.
Copahue, Central Chile-Argentina border
37.856°S, 71.183°W, Elevation 2953 m
SERNAGEOMIN reported that on 15 October gray ash plumes rose 300 m above Copahue’s El Agrio Crater and four explosions were recorded. Plumes on 17 October were generally white and rose 100 m; no explosions were detected. Seismicity was low on 18 October. Plumes on 19 October rose 300 m. Six explosions associated with ash emissions were recorded. Incandescence from the crater was detected in the evening. On 20 October the network recorded 12 explosions with associated ash emissions. During 20-21 October plumes rose 200 m, and crater incandescence at night was noted. SERNAGEOMIN maintained the Alert Level at Orange, and ONEMI maintained Level Yellow for Alto Biobío (40 km W) in the Biobío region (since 3 June 2013).
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.
Etna, Sicily (Italy)
37.734°N, 15.004°E, Elevation 3330 m
INGV reported that from the afternoon of 7 October through 16 October Etna's New Southeast Crater (NSEC) produced weak and intermittent explosive activity; small ash puffs were rapidly dispersed by the wind. During some nights small Strombolian explosions ejected incandescent material a few tens of meters above the crater rim.
Geologic summary: Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater (the latter formed in 1978). Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.
Karangetang [Api Siau], Siau Island (Indonesia)
2.78°N, 125.4°E, Elevation 1784 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 20 October ash plumes from Karangetang rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 75 km NW.
Geologic summary: Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, north of Sulawesi. The 1784-m-high stratovolcano contains five summit craters along a N-S line. Karangetang is one of Indonesia's most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented in the historical record (Catalog of Active Volcanoes of the World: Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts has also produced pyroclastic flows.
Mayon, Luzon (Philippines)
13.257°N, 123.685°E, Elevation 2462 m
PHIVOLCS reported that during 14-21 October white plumes rose from Mayon's crater and drifted NW, W, WSW, SW, and SE. On 14 October a seismic signal indicating a rockfall was recorded and a brief period of incandescence from the crater was observed. A few volcanic earthquakes were recorded during 18-21 October. On 19 October weak incandescence from the crater was noted. A new lava flow first observed that same day was 300-400 m long on 20 October based on an aerial survey. Weak crater incandescence from the lava dome was again seen on 21 October. The 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, Elevation 3067 m
JMA reported that cloud cover often prevented visual observations of Ontakesan during 15-21 October; white plumes rose 100-200 m above the crater rim and drifted NE and SE during 16-18 October. White plumes rose 600 m on 19 October. A news article from 17 October noted that the search for the seven people still missing from the 27 September eruption was stopped due to wintery conditions; the search was expected to resume in the springtime. 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. 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. Ascending this volcano is one of the major objects of religious pilgrimage in central Japan.
Poas, Costa Rica
10.2°N, 84.233°W, Elevation 2708 m
OVSICORI-UNA reported that a 1.5-minute-long phreatic eruption from the hot lake at Poás was recorded on 13 October starting at 0858. The event ejected material over 250 m from the crater lake, causing ashfall on the lookout area and visitor’s center. The phreatic eruptions in August and October were the most energetic events of the year.
Geologic summary: The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica's most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2708-m-high complex stratovolcano extends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water.
19.023°N, 98.622°W, Elevation 5426 m
CENAPRED reported that during an overflight of Popocatépetl on 14 October volcanologists observed that the diameter of the inner crater (formed in July 2013) had increased to 350 m. The bottom of the inner crater floor was 100 m below the floor of the main crater, cup-shaped, and covered with tephra. No sign of the 52nd lava dome, emplaced in early August 2014, was visible. Steam emissions originated from a crack in the N wall of the inner crater and ash emission came from the bottom of the crater. During 15-21 October seismicity indicated continuing emissions of water vapor, gas, and occasional small amounts of ash. Cloud cover sometimes prevented visual observations. Incandescence from the crater was observed most nights. Low-intensity explosions were detected on 17 and 19 October. The Alert Level remained at to 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.
3.17°N, 98.392°E, Elevation 2460 m
Based on webcam views and wind data models, the Darwin VAAC reported that during 15-20 October daily small eruptions from Sinabung generated ash plumes that rose to an altitude of 4.3 km (14,000 ft) a.s.l. The plumes drifted 55 km NW during 15-17 October and ESE on 19 October.
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.
Aira, Kyushu (Japan)
31.593°N, 130.657°E, Elevation 1117 m
JMA reported that three explosions from Showa Crater at Aira Caldera’s Sakurajima volcano ejected tephra as far as 1,300 m during 14-17 October. The Alert Level remained at 3 (on a scale of 1-5). The Tokyo VAAC reported that on 16, 18, and 21 October ash plumes rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l.and drifted S, SE, and NE.
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.
64.63°N, 17.53°W, Elevation 2009 m
During 15-21 October, IMO maintained Aviation Colour Code Orange due to continued activity at Bárdarbunga’s Holuhraun eruptive fissure. Subsidence of the Bárdarbunga Caldera continued at a rate of 30-40 cm per day, concentrated in the NE part of the caldera, and on 15 October was an estimated 0.75 cubic kilometers. On 18 October a M 5.4 earthquake was detected at 0940 in N Bárdarbunga making it one of the biggest earthquakes since the start of the eruption. The lava field continued to grow and the lava production continued at the same rate; the lava field was 60.7 square kilometers on 19 October.
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.
Chirpoi, Kuril Islands (Russia)
46.525°N, 150.875°E, Elevation 742 m
SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 15-16 October. Cloud cover obscured views on other days during 14-20 October. 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.
Dukono, Halmahera (Indonesia)
1.68°N, 127.88°E | Elevation 1335 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 15-19 October ash plumes from Dukono rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted 55-110 km NE, E, and NW.
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.
Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W | Elevation 1222 m
During 15-21 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 tephra 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 continued to be active, with several breakouts about 1.3 km upslope of the front, although it stopped advancing on 17 October. Along the S side of the main flow a narrow breakout flow traveled at a rate of 80 m/day. The leading edge of the flow remained 1.4 km upslope from Apa’a Street. Vegetation along the flow margins was burning. 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.
Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Elevation 3283 m
KVERT reported that during 10-17 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 10-11 and 15 October; cloud cover prevented views of the volcano on the other days. 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.
Shishaldin, Fox Islands (USA)
54.756°N, 163.97°W, Elevation 2857 m
AVO reported that, although cloud cover often obscured views of Shishaldin during 15-21 October, seismicity indicated that a low-level eruption was likely continuing. Elevated surface temperatures at the summit were periodically detected in cloud-free satellite images. Tremor and ground-coupled airwaves from small explosions were occasionally detected in seismic data. 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 | Elevation 924 m
On 16 October INGV reported that during the previous two months effusive activity continued at Stromboli from a vent at 650 m elevation. Lava flows traveled as far as the lower part of the Sciara del Fuoco. During the previous few weeks there were sporadic ash emissions from summit vents that were sometimes accompanied by ejected incandescent pyroclastic material.
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.
Zhupanovsky, Eastern Kamchatka (Russia)
3.589°N, 159.15°E | Elevation 2899 m
KVERT reported that an explosive eruption at Zhupanovsky continued during 10-17 October. Satellite images detected a thermal anomaly on the volcano during 10-12 October, and ash plumes that rose to an altitude of 9 km (29,500 ft) a.s.l. on 11 October and drifted 411 km NE during 11-12 October. Cloud cover prevented satellite views of the volcano on the other days. 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.