New Activity/Unrest
CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m
SERNAGEOMIN reported that visual observations of Chaitén were inhibited due to inclement weather during 10-12 June. Customs officers in the town of Chaitén reported noises on 11 June. They also reported the presence of two new craters to the S that emitted ash-and-gas plumes on 12 June. The plumes drifted S. Later that day in Chaitén town, an abrupt swelling of the river Chaitén was observed. Seismic events increased in number and intensity.
An overflight on 14 June revealed spines rising above the top of the new lava dome, which had grown in height to exceed the old dome. Gas, ash, and steam plumes were primarily emitted from a vent, about 100 m in diameter, at the SE contact between the old and the new lava dome. Previously, emissions came from the NW contact between the old and new domes. Continuous explosions produced ash plumes that rose to an altitude of 3 km (10,000 ft) a.s.l.caldera floor. The Alert Level remained at Red. and drifted E. Several other points of gas-and-steam emissions were seen along the contact. Small block-and-ash flows from the new dome had descended the S flank of the old dome and occasionally reached the
Based on observations of satellite imagery, SIGMET reports, and pilot observations, the Buenos Aires VAAC reported that during 11-16 June ash plumes rose to altitudes of 2.1-3.7 km (7,000-12,000 ft) a.s.l. and drifted N, NE, and E.
Geologic Summary. Chaitén is a small, glacier-free caldera with a Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf of Corcovado. A pyroclastic-surge and pumiceobsidian lava dome occupies much of the caldera floor. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km away from the volcano to the north and south. The caldera is breached on the SW side by a river that drains to the bay of Chaitén, and the high point on its southern rim reaches 1122 m. deposit considered to originate from the eruption that formed the elliptical 2.5 x 4 km wide summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-high
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Buenos Aires Volcanic Ash Advisory Center (VAAC)
Chaitén Information from the Global Volcanism Program
GORELY Southern Kamchatka 52.558°N, 158.03°E; summit elev. 1829 m
KVERT reported that seismic activity in the area of Gorely and Mutnovsky volcanoes increased on 13 June. There is only one seismic station in the area of the two volcanoes, so the source of the seismicity could not be determined. Activity was not visually noted and satellite imagery was not available at the time of the seismicity increase. The level of Concern Color Code was raised to Yellow on 14 June.
Geologic Summary. Gorely volcano, one of the most active in southern Kamchatka, consists of five small overlapping stratovolcanoes constructed along a WNW-ESE line within a large 9 x 13.5 km late-Pleistocene caldera. The massive Gorely complex contains 11 summit and 30 flank craters. During the early Holocene, activity was characterized by frequent mild eruptions with occasional larger explosions and lava flows that filled in the caldera. Quiescent periods became longer between 6,000 and 2,000 years ago, after which the activity was mainly explosive. About 600-650 years ago intermittent strong explosions and lava flow effusion accompanied frequent mild eruptions. Historical eruptions have consisted of vulcanian and phreatic explosions of moderate volume.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Gorely Information from the Global Volcanism Program
MUTNOVSKY Southern Kamchatka 52.453°N, 158.195°E; summit elev. 2322 m
KVERT reported that seismic activity in the area of Gorely and Mutnovsky volcanoes increased on 13 June. There is only one seismic station in the area of the two volcanoes, so the source of the seismicity could not be determined. Activity was not visually noted and satellite imagery was not available at the time of the seismicity increase. The level of Concern Color Code was raised to Yellow on 14 June.
Geologic Summary. Massive Mutnovsky, one of the most active volcanoes of southern Kamchatka, is formed of four coalescing stratovolcanoes of predominately basalticHolocene activity was characterized by mild-to-moderate phreatic and phreatomagmatic eruptions from the summit crater. Historical eruptions have been explosive, with lava flows produced only during the 1904 eruption. Geothermal development is planned at Mutnovsky, which has the highest heat capacity of any volcano in the Kuril-Kamchatka arc. composition. Multiple summit craters cap the volcanic complex. Growth of Mutnovsky IV, the youngest cone, began during the early Holocene. An intracrater cone was constructed along the northern wall of the 1.3-km-wide summit crater. Abundant flank cinder cones were concentrated on the SW side.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Mutnovsky Information from the Global Volcanism Program