Ubinas is an active stratovolcano in southwestern Peru. It is Peru's most active volcano. The upper slopes of the stratovolcano, compose primarily of Pleistocene andesitic lava flows, steepen to nearly 45 degrees. The steep-walled, 1.4 km wide and 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 extend 10 km from the volcano.