Instituto Geofísico del Perú (IGP) reported that a lahar descended the NW flank of El Misti at 1640 on 5 February, impacting the Matagente drainage.

Geological Summary. El Misti is a symmetrical andesitic stratovolcano with nested summit craters immediately NE of the city of Arequipa, Peru. Eruptions from the active cone began about 13,700 and 11,300 years ago, within a 1.5 x 2 km caldera that underwent collapse about 50,000 years ago. A large scoria cone has grown with the 830-m-wide outer summit crater. At least 20 tephra-fall deposits and numerous pyroclastic-flow deposits have been documented during the past 50,000 years, including a pyroclastic flow that traveled 12 km S about 2,000 years ago. The most recent activity has been dominantly pyroclastic, and strong winds have formed a parabolic dune field of volcanic ash extending up to 20 km downwind. An eruption in the 15th century affected nearby Inca inhabitants. Some reported eruptions may represent increased fumarolic activity.

Source: Instituto Geofísico del Perú (IGP)