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Report on Ubinas (Peru) — 7 June-13 June 2006


Ubinas

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 7 June-13 June 2006
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2006. Report on Ubinas (Peru) (Sennert, S, ed.). Weekly Volcanic Activity Report, 7 June-13 June 2006. Smithsonian Institution and US Geological Survey.

Weekly Report (7 June-13 June 2006)

Ubinas

Peru

16.345°S, 70.8972°W; summit elev. 5608 m

All times are local (unless otherwise noted)


Based on pilot reports, ash clouds identified from Ubinas during 9-11 June reached altitudes of 6.7 km (22,000 ft) a.s.l. and drifted E and SW. According to news articles, approximately 550 families were evacuated on 10 and 11 June.

Geological Summary. The truncated appearance of Ubinas, Perú's most active volcano, is a result of a 1.4-km-wide crater at the summit. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front. The growth and destruction of Ubinas I was followed by construction of Ubinas II 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°. The steep-walled, 150-m-deep summit crater 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 about 3,700 years ago extend 10 km from the volcano. Widespread Plinian pumice-fall deposits include one from about 1,000 years ago. Holocene lava flows are visible on the flanks, but activity documented since the 16th century has consisted of intermittent minor-to-moderate explosive eruptions.

Sources: Living in Peru, Buenos Aires Volcanic Ash Advisory Center (VAAC)