Ubinas is Peru’s most recently active volcano. Until 2006, this stratovolcano had not erupted for about 40 years. Ubinas is located in southwestern Peru. The upper slopes of the volcano, composed 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. The volcano is a composite cone built on a high plateau formed from Oligo-Miocene ignimbrites and intrusive rocks of upper Tertiary age.