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Report on Guagua Pichincha (Ecuador) — 28 November-4 December 2001

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 November-4 December 2001
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2001. Report on Guagua Pichincha (Ecuador). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 28 November-4 December 2001. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (28 November-4 December 2001)


Guagua Pichincha

Ecuador

0.171°S, 78.598°W; summit elev. 4784 m

All times are local (unless otherwise noted)


Tremor was recorded at Guagua Pichincha for ~16 hours after a phreatic eruption on 26 November. Signals from a relatively high number of rockfalls were recorded on seismographs, which is normal after an explosion. Two new craters formed during the explosion N of the 1981 crater. The following day, dark steam was observed rising 5 m above the craters. Volcanic and seismic activity remained at low levels after the 27th, with only low-level fumarolic activity occurring.

Geologic Background. Guagua Pichincha and the older Pleistocene Rucu Pichincha stratovolcanoes form a broad volcanic massif that rises immediately to the W of Ecuador's capital city, Quito. A lava dome is located at the head of a 6-km-wide breached caldera that formed during a late-Pleistocene slope failure ~50,000 years ago. Subsequent late-Pleistocene and Holocene eruptions from the central vent in the breached caldera consisted of explosive activity with pyroclastic flows accompanied by periodic growth and destruction of the central lava dome. One of Ecuador's most active volcanoes, it is the site of many minor eruptions since the beginning of the Spanish era. The largest historical eruption took place in 1660, when ash fell over a 1000 km radius, accumulating to 30 cm depth in Quito. Pyroclastic flows and surges also occurred, primarily to then W, and affected agricultural activity, causing great economic losses.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)