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Report on Cayambe (Ecuador) — 18 February-24 February 2004


Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
18 February-24 February 2004
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2004. Report on Cayambe (Ecuador). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 18 February-24 February 2004. Smithsonian Institution and US Geological Survey.

Weekly Report (18 February-24 February 2004)



0.029°N, 77.986°W; summit elev. 5790 m

All times are local (unless otherwise noted)

On 29 January a swarm of ~148 small volcano-tectonic earthquakes occurred at Cayambe. By 1 February seismicity had decreased, reaching "normal" base levels. IG reported that the swarm may have represented an increase in the internal pressure of the volcano due to the arrival of fluid, possibly magma.

Geological Summary. The massive compound andesitic-dacitic Cayambe stratovolcano is located on the western edge of the Cordillera Real, east of the Inter-Andean Valley. The volcano, whose southern flank is on the equator, is capped by extensive glaciers. The modern Nevado Cayambe, constructed to the east of older Pleistocene volcanic complexes, contains two summit lava domes about 1.5 km apart. Several other lava domes on the upper flanks have been the source of pyroclastic flows that reached the lower flanks. A prominent Holocene pyroclastic cone on the lower E flank, La Virgen, fed thick andesitic lava flows that traveled about 10 km E. Nevado Cayambe has also produced frequent explosive eruptions beginning about 4,000 years ago, with the most recent known activity during 1785-86.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)