Report on Guagua Pichincha (Ecuador) — 1 November-7 November 2000
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
1 November-7 November 2000
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2000. Report on Guagua Pichincha (Ecuador). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 1 November-7 November 2000. Smithsonian Institution and US Geological Survey.
0.171°S, 78.598°W; summit elev. 4784 m
All times are local (unless otherwise noted)
During the week moderate explosive activity produced small ash clouds at Guagua Pichincha. The Washington VAAC reported that one such cloud was visible on GOES-8 imagery at 0956 on 1 November and the IG reported that the ash cloud was near the summit level (~5 km a.s.l.). The IG also reported that seismicity continued after the eruption, suggesting that further explosive activity was possible. Small explosions and seismic activity suggested that dome growth occurred. The volcano is at Alert Level Yellow.
Geological Summary. 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.