Report on Cotopaxi (Ecuador) — 28 December-3 January 2023
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 28 December-3 January 2023
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2022. Report on Cotopaxi (Ecuador) (Sennert, S, ed.). Weekly Volcanic Activity Report, 28 December-3 January 2023. Smithsonian Institution and US Geological Survey.
0.677°S, 78.436°W; summit elev. 5911 m
All times are local (unless otherwise noted)
IG reported that the low-level eruption at Cotopaxi continued during 28 December 2022-3 January 2023, characterized by daily steam-and-gas emissions with occasional low ash content. Several gas-and-steam emissions with low ash content were visible on 28 December rising 600-900 m above the summit and drifting W. Sulfur dioxide emissions were 1,314-2,550 tons per day during 27-28 December based on satellite data. Only gas emissions were visible during 29 December-2 January, though weather clouds often prevented webcam and satellite observations. At 1740 on 3 January a diffuse ash plume rose 1 km above the summit and drifted W, based on a satellite image. Minor ashfall was possible in areas to the W. 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.