Active volcanoes in the world: July 30 - August 5, 2014

Active volcanoes in the world: July 30 - August 5, 2014

New activity/unrest was observed at 4 volcanoes from July 30 - August 5, 2014. Ongoing activity was reported for 1o volcanoes.

New activity/unrest: Kuchinoerabujima, Ryukyu Islands (Japan)  | Kusatsu-Shiranesan, Honshu (Japan)  | Tungurahua, Ecuador  | Ubinas, Peru

Ongoing activity: Aira, Kyushu (Japan)  | Fuego, Guatemala  | Kilauea, Hawaiian Islands (USA)  | Pacaya, Guatemala  | Reventador, Ecuador  | San Miguel, El Salvador  | Santa Maria, Guatemala  | Shishaldin, Fox Islands (USA)  | Shiveluch, Central Kamchatka (Russia)  | Zhupanovsky, Eastern Kamchatka (Russia)

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 23:00 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail.

New activity/unrest

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

On 3 August, JMA reported that Kuchinoerabujima erupted in the vicinity of Shin-dake crater and an overflight confirmed traces of ash on the west side of the volcano. Tokyo VAAC reported an ash plume rose to 1.5 km (5,000 ft) a.s.l. and drifted N. JMA raised the Alert Level for Kuchinoerabujima from 2 to 3 (on a scale of 1-5). On 5 August, volcanic seismicity and volcanic tremor decreased and views from a remote web camera showed a white plume 50 m above the crater rim.

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.

Kusatsu-Shiranesan, Honshu (Japan)
6.618°N, 138.528°E, Summit elev. 2165 m

On 5 August, JMA reported a notable increase of volcanic earthquakes at Kusatsu-Shiranesan’s crater, although tremor was absent. The Alert Level remains at 2 (on a scale of 1-5).

Geologic summary: The summit of Kusatsu-Shiranesan volcano, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes. The andesitic-to-dacitic volcano was formed in three eruptive stages beginning in the early to mid Pleistocene. The Pleistocene Oshi pyroclastic flow produced extensive welded tuffs and non-welded pumice that covers much of the east, south and SW flanks. The latest eruptive stage began about 14,000 years ago. All historical eruptions have consisted of phreatic explosions from the acidic crater lakes or their margins. Fumaroles and hot springs that dot the flanks have strongly acidified many rivers draining from the volcano. The crater was the site of active sulfur mining for many years during the 19th and 20th centuries.

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

During 30 July-5 August IG reported that Tungurahua had moderate and increasing levels of seismicity. On 1-4 August ash plumes rose 1-4 km (3,300-13,100 ft) a.s.l. and drifted N, NW, W, SW, and E. Incandescent blocks ejected 700-1000m above the crater and traveled 500-700m down the flanks of Tungurahua from an explosion on 1 August, followed by 4 small to moderate explosions on 3 August and an explosion 4 August that rattled the observatory. IG reported incandescence within the crater on 2-4 August; observations were supplemented with a thermal camera when the summit was obscured by clouds. Washington VAAC reported ash emissions on 1-5 August that rose 6-8.5 km (20,000-28000 ft) a.s.l. Ashfall was reported in Choglontús, El Manzano, Motilones, Cusúa, Tisaleo, Mocha, Bilbao, Pillate, Chacauco, Pondoa, Sua, Cevallos, Motilones, Quero, Rumipamba, Yanayacu, Pinchicoto, and Tizaleo.

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 volcanic 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. They have been 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.

Ubinas, Peru
16.355°S, 70.903°W, Summit elev. 5672 m

On 31 July and 3-5 August the Buenos Aires VAAC reported continuous emission of light ash from Ubinas. On 30 July INGEMMET reportedsteam-and-gas plumes that rose 500-1100 m above the summit. On 31 July INGEMMET reported an eruption column rose to 3 km (9,800 ft) a.s.l. and drifted NW. On 1 and 3 August gas-and-ash emission rose 200-1200 m above the crater and drifted W.

Geologic summary: A small, 1.4-km-wide caldera cuts the top of Ubinas, Peru's most active volcano, giving it a truncated appearance. Ubinas is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Perú. The growth and destruction of Ubinas I volcano was followed by construction of Ubinas II volcano beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank of Ubinas about 3700 years ago extend 10 km from the volcano. Widespread plinian pumice-fall deposits from Ubinas include one of Holocene age about 1000 years ago. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.

Ongoing activity

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

JMA reported an explosion from Showa Crater at Aira Caldera’s Sakurajima volcano on 30 July that ejected ballistics 300-500 m from Showa crater and six other explosions on 31 July accompanied by volcanic earthquakes and volcanic tremor. In general, explosions, volcanic tremor and volcanic earthquakes decreased 1-4 August. On 31 July-4 August, incandescence was clearly visible by high-sensitivity camera at night. The Tokyo VAACreported that a plume from the 30 July explosion rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted NW. The Alert Level remained at 3 (on a scale of 1-5).

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.

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

During 30 July-5 August, INSIVUMEH reported weak to moderate explosions at Fuego with incandescent blocks expelled 100-200 m above the crater accompanied by minor gray ash 300-400 m above the crater that drifted S. Shock waves from those explosions produced rumbling that rattled structures up to 4 km from the volcano. On most days, weak to moderate avalanches of blocks moved down the flanks towards Taniluya, Ceniza and Santa Teresa canyons. Gray to white plumes rose 4.2-4.6 km (13,800-15,100 ft) a.s.l. and drifted 9-12 km W and SW. Ashfall was reported in villages of Yepocapa, Finca La Conchita, Sangre de Cristo, Morelia and Panimaché.

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.

Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Summit elev. 1222 m

During 30 July-5 August 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 deposited several kilometers away.

On 30 June the mapped June 27th flow front had reached 4.2 km from vent on northeast flank of Pu’u ‘O’o’. The flow front has continued to advance reaching about 5 km NE of Pu’u ‘O’o’ on 4 August. Two small lava ponds remained active on the south side of Pu’u ‘O’o’s crater. On 30 July-2 August small lava flows were fed by the eastern lava pond.

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.

Pacaya, Guatemala
14.381°N, 90.601°W, Summit elev. 2552 m

INSIVUMEH reported that during 30 July-5 August, white to light blue fumarolic plumes rose 50 m above Mackenney Crater at Pacaya and drifted up to 600 m W, SW, and S.

Geologic summary: Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. Pacaya is a complex basaltic volcano constructed just outside the southern topographic rim of the 14 x 16 km Pleistocene Amatitlán caldera. A cluster of dacitic lava domes occupies the southern caldera floor. The post-caldera Pacaya massif includes the ancestral Pacaya Viejo and Cerro Grande stratovolcanoes and the currently active Mackenney stratovolcano. Collapse of Pacaya Viejo volcano between 600 and 1500 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (Mackenney cone) grew. A subsidiary crater, Cerro Chino, was constructed on the NW somma rim and was last active in the 19th century. During the past several decades, activity at Pacaya has consisted of frequent strombolian eruptions with intermittent lava flow extrusion that has partially filled in the caldera moat and armored the flanks of Mackenney cone, punctuated by occasional larger explosive eruptions that partially destroy the summit of the growing young stratovolcano.

Reventador, Ecuador
0.077°S, 77.656°W, Summit elev. 3562 m

IG reported moderate volcanic activity including explosions, long period earthquakes, harmonic tremor, and tremor at Reventador during 30 July-5 August. On most days IG reported inclement weather with intermittent views of steam-and-ash plumes that rose above the crater and drifted W. On 2 August IG noted a steam-and-ash plume rose 2 km above the crater accompanied by seven emission tremor events. On 31 July Washington VAACreported on-going ash emissions and detected hotspots at the crater.

Geologic summary: Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic Volcán El Reventador stratovolcano rises to 3562 m above the jungles of the western Amazon basin. A 4-km-wide caldera widely breached to the east was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1300 m above the caldera floor to a height comparable to the caldera rim. It has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. The largest historical eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.

San Miguel, El Salvador
13.434°N, 88.269°W, Summit elev. 2130 m

SNET reported decreasing seismic activity and reduced emissions at San Miguel during 30 July-5 August. A remote camera and infrared visual display showed minor white fumarolic emissions that rose less than 200 m above the crater.

Geologic summary: The symmetrical cone of San Miguel volcano, one of the most active in El Salvador, rises from near sea level to form one of the country's most prominent landmarks. The unvegetated summit of the 2130-m-high volcano rises above slopes draped with coffee plantations. A broad, deep crater complex that has been frequently modified by historical eruptions (recorded since the early 16th century) caps the truncated summit of the towering volcano, which is also known locally as Chaparrastique. Radial fissures on the flanks of the basaltic-andesitic volcano have fed a series of historical lava flows, including several erupted during the 17th-19th centuries that reached beyond the base of the volcano on the north, NE, and SE sides. The SE-flank lava flows are the largest and form broad, sparsely vegetated lava fields crossed by highways and a railroad skirting the base of the volcano. The location of flank vents has migrated higher on the edifice during historical time, and the most recent activity has consisted of minor ash eruptions from the summit crater.

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

On 30 July-5 August INSIVUMEH reported weak fumerolic columns rose to 2.7-2.8 km (8,800-9,100 ft) a.s.l. above Santiaguito. On most days, weak avalanches flowed from the lava flow (2.1 km in length) towards Canyon Nima River I. On 4 August INSIVUMEH reported incandescence at the crater.

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 of Volcán Santa María 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.

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

AVO reported that during 30 July-5 August low-level eruptive activity continued at Shishaldin volcano. Elevated surface temperatures at the summit were detected from satellite data most days except for cloudy conditions 4-5 August. Steaming from the summit crater was visible in web cam images 30 July-1 August and 5 August. 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.

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

KVERT reported that during 25 July-1 August lava-dome extrusion onto Shiveluch’s SE flank was accompanied by moderate ash explosions, incandescence of the dome summit, hot avalanches, and fumarolic activity. Satellite images were obscured by clouds over the past week. The Aviation Color Code remained at Orange.

Geologic summary: The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km Shiveluch 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 of Shiveluch 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.

Zhupanovsky, Eastern Kamchatka (Russia)
53.59°N, 159.147°E  | Summit elev. 2958 m

KVERT reported that during 25 July-1 August the moderate explosive eruption continues at Zhupanovsky. On 27 July, satellite data showed ash plumes rose to 4 km (13,100 ft) a.s.l. and extended 150 km N. The volcano was obscured by clouds 25 July-1 August. On 30 July Tokyo VAAC reported an ash plume rose 5.2 km (17,000 ft) a.s.l. and drifted W.

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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