IG reported that the eruption at Cotopaxi continued during 14-21 February, characterized by almost daily emissions of gas, steam, and ash; inclement weather conditions occasionally prevented views. Gas emissions with some ash rose as high as 600 m above the crater rim and drifted E, SE, and SW during 14-15 February. Minor ashfall was noted in San Ramón (17 km SW), Ticatilín (15 km WSW), San Agustín del Callo (18 km WSW), Mulaló (19 km SW), and Lasso (20 km WSW). Daily ash-and-gas plumes rose as high as 1.1 km during 16-19 February and drifted mainly E, SE, S, and SW. Minor amounts of ash occasionally fell on the downwind flanks. During 20-21 February steam-and-gas plumes rose as high as 1.3 km and drifted E and SW. Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).

Geological Summary. The symmetrical, glacier-covered, Cotopaxi stratovolcano is Ecuador's most well-known volcano and one of its most active. The steep-sided cone is capped by nested summit craters, the largest of which is about 550 x 800 m in diameter. Deep valleys scoured by lahars radiate from the summit of the andesitic volcano, and large andesitic lava flows extend to its base. The modern edifice has been constructed since a major collapse sometime prior to about 5,000 years ago. Pyroclastic flows (often confused in historical accounts with lava flows) have accompanied many explosive eruptions, and lahars have frequently devastated adjacent valleys. Strong eruptions took place in 1744, 1768, and 1877. Pyroclastic flows descended all sides of the volcano in 1877, and lahars traveled more than 100 km into the Pacific Ocean and western Amazon basin. Smaller eruptions have been frequent since that time.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)