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Report on Ubinas (Peru) — 14 July-20 July 2010

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 July-20 July 2010
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2010. Report on Ubinas (Peru). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 July-20 July 2010. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (14 July-20 July 2010)


Ubinas

Peru

16.355°S, 70.903°W; summit elev. 5672 m

All times are local (unless otherwise noted)


Based on a pilot observation and analyses of satellite imagery, the Buenos Aires VAAC reported that on 18 July an ash plume from Ubinas drifted NE. A subsequent report about 12 hours later stated that no further activity was seen.

Geologic Background. A small, 1.4-km-wide caldera cuts the top of Ubinas, Peru's most active volcano, giving it a truncated appearance. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of PerĂº. 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 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 about 3700 years ago extend 10 km from the volcano. Widespread plinian pumice-fall deposits include one of Holocene age about 1000 years ago. Holocene lava flows are visible on the flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)