Ubinas (Peru)

Status Unrest Eruption 2017 5672m
Stratovolcano (Subduction zone / Continental crust (> 25 km))

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 Perú. 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.

Volcán Ubinas, seen here from the west, is Perú's most active volcano. A small, 1.2-km-wide caldera that cuts the top of Ubinas gives it a truncated appearance. The upper slopes of the stratovolcano steepen to nearly 45 degrees. The steep-walled, 150-m-deep caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200-m deep. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor explosive eruptions.

Photo by Norm Banks, 1988 (U.S. Geological Survey).

Last updated 2023-12-18 23:20:20