During 6-9 August INGEMMET reported that the eruption of Ubinas was continuing. On 6-7 August gas-and-minor ash emissions rose 300-1200 m above the crater and drifted NE and S. On 6 August ash was reported in the village of Para (NE). On 8-9 August, white emissions of primarily water vapor rose 100-300 m above the crater and drifted S and SE. On 6 August Buenos Aires VAAC reported intermittent light volcanic ash and emission puffs to 6.7 km (22,000 ft)a.s.l. and continuous emissions of gases and light ash on 7 August.

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: Instituto Geológico Minero y Metalúrgico (INGEMMET), Buenos Aires Volcanic Ash Advisory Center (VAAC)