The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.

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CAYAMBE Ecuador 0.029°N, 77.986°W; summit elev. 5790 m; All times are local (= UTC - 5 hours)

Reports from 2003: | November |
Reports from 2004: | February |
Reports from 2005: | September |

Background. The massive compound Cayambe stratovolcano is located on the isolated western edge of the Cordillera Real. The 5,790-m-high volcano, whose southern flank lies astride the equator, is capped by glaciers, which descend down to 4,200 m on the eastern Amazonian side. The modern Nevado Cayambe volcano, constructed to the E of an older volcanic complex, contains two summit lava domes located about 1.5 km apart, the western of which is the highest. Several other lava domes on the upper flanks have been the source of pyroclastic flows that reached the lower flanks of the volcano. A prominent Holocene pyroclastic cone on the lower eastern flank fed thick lava flows that traveled about 10 km to the E. Nevado Cayambe was recently discovered to have produced frequent explosive eruptions during the Holocene, and to have had a single historical eruption, during 1785-86.

Map

Cayambe Information from the Global Volcanism Program

12-18 November 2003

During 3-9 November, about nine earthquakes occurred per day at Cayambe, near the daily average since August 2003 and about twice the daily average of 4 per day before that. Seismicity also included small clusters of tectonic earthquakes with magnitudes less than 3. There were reports of a strong scent of sulfur in the sector of Picos Jarrína at an elevation of ~5,460 m. The scent was strongest near cracks.

Source: Instituto Geofísico-Escuela Politécnica Nacional

18-24 February 2004

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.

Source: Instituto Geofísico-Escuela Politécnica Nacional

14-20 September 2005

During 16-18 September, a cluster of 330 small earthquakes occurred at Cayambe. The earthquakes reached a maximum magnitude of 3.6. They occurred on the volcano's SW flank, where previous clusters had been located. The cluster had not reached the level of one that took place in March of 2004. IG reported that these types of clusters occur fairly regularly at Cayambe and could be related to changes in the internal pressure of the volcano. The earthquakes continued through at least 19 September.

Source: Instituto Geofísico-Escuela Politécnica Nacional