New activity/unrest was observed at 4 volcanoes from May 28 - June 3, 2014. Ongoing activity was reported for 9 volcanoes.
New activity/unrest: Pavlof, United States | San Miguel, El Salvador | Sangeang Api, Indonesia | Santa María, Guatemala
Ongoing activity: Aira, Kyushu (Japan) | Dukono, Halmahera (Indonesia) | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Merapi, Central Java (Indonesia) | Shishaldin, Fox Islands (USA) | Shiveluch, Central Kamchatka (Russia) | Ubinas, Peru
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.
Pavlof, United States
55.42°N, 161.887°W, Summit elev. 2519 m
AVO reported that on 31 May elevated surface temperatures were detected over Pavlof in satellite images, suggesting a low-level eruption with lava. Observers camping near the volcano confirmed lava and noted that flows were originating from a vent on the NE flank. A low-level steam plume was visible in satellite images and recorded by the FAA web-cam located in Cold Bay. Several pilots observed a gas-and-ash plume drifting N at altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. The Aviation Color Code was raised to Orange and the Volcano Alert Level was raised to Watch. Small explosion signals were detected by a distant infrasound sensor. Later that night weak incandescence from the summit was observed in the webcam. On 1 June clouds obscured web-cam views and ash plumes were not detected in satellite images. The seismic network detected weak activity.
Activity escalated on 2 June, prompting AVO to raise the Aviation Color Code to Red and the Volcano Alert Level to Warning. Seismic tremor increased at 1500 and pilots observed ash plumes at altitudes of 6.7 km (22,000 ft) a.s.l. Satellite images showed a plume drifting more than 80 km E. Seismicity started to decrease at 2300. The web cam recorded intense lava fountaining at the summit and incandescence from a spatter-fed lava flow on the N flank. On 3 June seismicity again increased and pilots observed ash-and-steam plumes at altitudes of 7.3 km (24,000 ft) a.s.l. that drifted SSW. Later that day AVO lowered the Aviation Color Code to Orange and the Volcano Alert Level to Watch due to a decrease and stabilization of volcanic tremor. Satellite and webcam images showed two distinct parts of the plume: gas and steam with minor amounts of ash rose high above the volcano and drifted S, while pyroclastic flows on the N flank produced diffuse ash that caused hazy air and variable concentrations of ash below 3 km (10,000 ft) a.s.l. Winds were likely to push ash at lower altitudes WSW.
Geologic summary: The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing strombolian to vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption of Pavlof took place in 1911, at the end of a 5-year-long eruptive episode. During this eruption a fissure opened on the northern flank of the volcano, ejecting large blocks and issuing lava flows.
San Miguel, El Salvador
13.434°N, 88.269°W, Summit elev. 2130 m
According to SNET in a report from 1 June, the Ministerio de Medio Ambiente y Recursos Naturales (MARN) reported that seismicity at San Miguel remained high. Locals observed more intense gas plumes rising from the crater with occasional minor amounts of ash, especially after rainfall. Rumbling was also reported.
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.
Sangeang Api, Indonesia
8.2°S, 119.07°E, Summit elev. 1949 m
PVMBG reported that during January-29 May diffuse white plumes rose at most 25 m above Sangeang Api's crater. On 30 May seismicity increased, with tremor starting at 0500 and becoming continuous at 1348. An eruption at 1555 generated an ash plume that rose 3 km and drifted W, causing ashfall over the sea. The Alert Level was raised to 3 (on a scale of 1-4). The island has no permanent settlements, and is only occupied during the growing and harvest seasons; civil authorities evacuated 135 people to the mainland. Based on satellite images, pilot observations, and the Indonesian Meteorological Office, the Darwin VAAC reported that on 30 May an ash plume rose to an altitude of 15.2 km (50,000 ft) a.s.l. and drifted 440 km E and 750 km SE.
BNPB reported that on 31 May two larger explosions occurred at 1330 and 2242. According to the VAAC, ash plumes from those explosions rose to altitudes of 13.7-15.2 km (45,000-50,000 ft) a.s.l. and drifted 280 km NW and other various directions. Later in the day the ash plumes became detached. Ashfall affected many areas in the Bima Regency on the mainland, including Wera, and prompted the evacuation of 7,328 people from four villages within a radius of 8 km from Sangeang Api. The Bima and Tambolaka airports were temporarily closed. According to a news article, all flights to and from the Darwin International Airport in Australia on 31 May were canceled.
The VAAC noted that ash plumes rose to an altitude of 4.3 km (14,000 ft) a.s.l. on 1 June and drifted W and SW. During 2-3 June ash plumes rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l. and drifted 45 km W.
Geologic summary: Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-
Santa María, Guatemala
14.756°N, 91.552°W, Summit elev. 3772 m
INSIVUMEH reported that on 29 May a hot lahar descended the Nimá I river drainage on the S flank of Santa María's Santiaguito lava-dome complex, carrying blocks up to 50 cm in diameter as well as tree trunks and branches. The lahar was 25 m wide and 3 m deep and had a strong sulfur odor. Explosions during 31 May-1 June generated ash plumes that rose 600 m and drifted W and SW. Lahars on 1 and 3 June descended and caused flooding in the Nimá I, San Isidro (S), and Samala (E and S) rivers. On 2 June explosions produced ash plumes that rose 500 m, drifted W, and caused ashfall in Monte Bello and Loma Linda. Hot lahars with a sulfur odor again descended Nimá I. On 3 June a lava flow slowly descended the E flank of the dome.
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.
Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m
Based on JMA notices, the Tokyo VAAC reported that on 31 May explosions from Aira Caldera’s Sakurajima volcano generated plumes that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W.
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.
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 28 May ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 75 km NW. The next day an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 65 km W. On 3 June ash plumes rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 55 km 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. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
14.473°N, 90.88°W, Summit elev. 3763 m
INSIVUMEH reported that during 31 May-1 June explosions at Fuego produced ash plumes that rose 350-550 m above the crater and drifted 8 km WNW. During the afternoon and evening of 1 June lahars descended the Las Lajas (SE) and Honda (E) drainages, as well as the Seca (W) drainage which disrupted traffic. Other sections of roadway to the W and S were also affected. Heavy rain continued on 2 June; lahars descended the Las Lajas and El Jute (SE) drainages, carrying blocks as large as 1.5 m in diameter. Explosions during 2-3 June generated ash plumes that rose 550-650 m and drifted 8 km S and SW. Incandescence rose above the crater and avalanches descended the Taniluyá (SW), Trinidad (S), and Ceniza (SSW) drainages.
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 volcano dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta volcano 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 volcano, eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.
Karymsky, Eastern Kamchatka (Russia)
54.05°N, 159.45°E, Summit elev. 1536 m
KVERT reported that Strombolian and weak Vulcanian activity continued at Karymsky during 23-30 May. Satellite images detected a thermal anomaly over the volcano on 25 and 27 May. The Aviation Color Code remained at Orange.
Geologic summary: Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, which is located immediately south of Karymsky volcano. The caldera enclosing Karymsky volcano formed about 7600-7700 radiocarbon years ago; construction of the Karymsky 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 28 May-3 June 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 spatter cones on the N, NE, SE, and S portions of the crater floor. During 30 May-1 June the small lava lake in the NE spatter cone briefly overflowed its rim each morning. On 22 May geologists mapped the farthest point of activity from the Kahauale’a 2 lava flow, 8.4 km NE of Pu’u 'O'o; on 30 May they mapped three small breakouts 1.8-6.2 km from Pu’u 'O'o.
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.
Merapi, Central Java (Indonesia)
7.542°S, 110.442°E, Summit elev. 2968 m
PVMBG reported that during 16-22 May seismicity at Merapi fluctuated at normal levels and deformation measurements showed no significant changes. Solfatara plumes rose 300 m and drifted W on 27 May. The Alert Level remained at 1 (on a scale of 1-4) on 23 May.
Geologic summary: Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. Merapi is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi volcano beginning during the Pleistocene ended with major edifice collapse perhaps about 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory.
Shishaldin, Fox Islands (USA)
54.756°N, 163.97°W, Summit elev. 2857 m
AVO reported that, although cloud cover frequently obscured views of Shishaldin during 28 May-3 June, elevated surface temperatures at the summit were detected in satellite images, and minor steam emissions were observed in webcam images. 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, Shishaldin 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. Shishaldin contains 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 23-30 May lava-dome extrusion onto Shiveluch’s SE flank was accompanied by ash explosions, incandescence, hot avalanches, and fumarolic activity. An explosion on 26 May generated an ash plume that rose as high as 10 km (32,800 ft) a.s.l. and drifted 800 km SSE. Satellite images detected a thermal anomaly over the dome during 23-25 and 27-28 May. 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
16.355°S, 70.903°W, Summit elev. 5672 m
Observatorio Vulcanológico del INGEMMET (OVI) reported that during 28-29 May ash emissions at Ubinas continued; gas-and-ash plumes rose 0.6-2.5 km above the crater and drifted ESE. Ashfall was reported in various towns downwind of the plumes, including Querapi (4 km S), Ubinas (6.5 km SSE), Escacha, Chojata, San Miguel, and Tonohaya. The Buenos Aires VAAC reported that seismicity fluctuated during 2-3 June. Satellite and webcam images as well as pilot observations indicated continuous emission of gas and ash that rose to altitudes of 6.7-10.7 km (22,000-35,000 ft) a.s.l. and drifted NE, E, and SE.
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.