COTOPAXI Ecuador 00.677S, 78.436W; summit elev. 5,911 m; All times are local (= UTC - 5 hours)

Reports from 2003: | November-December |
Reports from 2004: | January |
Reports from 2005: | August |

Cotopaxi Information from the SI/USGS Global Volcanism Program

26 November- 2 December 2003
During 10-16 November, seismicity at Cotopaxi was at moderate levels, although it had increased in comparison to previous weeks. During the report period, seismicity was dominated by long-period earthquakes. Since late October volcano-tectonic earthquakes occurred beneath the zone of Pita and beneath the volcano's edifice. These events were less than M 3 and were not felt by the local population.

Source: Instituto Geofisico-Escuela Politecnica Nacional

17-23 December 2003
Seismicity at Cotopaxi during 8-14 December was above background levels, much like the previous week. During the report period, there was an increase in high-frequency tremor, but it remained within "normal" limits. A weak scent of sulfur was reported and steam columns rose to low levels.

Source: Instituto Geofisico-Escuela Politecnica Nacional

24-30 December 2003
During 15-21 December, there was a slight reduction in the level of seismicity at Cotopaxi in comparison to the previous week. The number of long-period earthquakes increased around 20 December. No volcano-tectonic earthquakes were recorded. Only fumarolic activity was observed at the volcano.

Source: Instituto Geofisico-Escuela Politecnica Nacional

7-13 January 2004

During 29 December to 4 January, the number of earthquakes at Cotopaxi slightly increased in comparison to the previous week. On 2 January a strong smell of sulfur was reported in the Yanasacha area.

Source: Instituto Geofisico-Escuela Politecnica Nacional

17-23 August 2005

A seismic anomaly that began at Cotopaxi in late July continued through 14 August. During this period, there was an increase in the number of long-period earthquakes in comparison to previous months. The earthquakes were less than M 3 and occurred at depths between 1 and 2 km below the volcano. Several of the earthquakes correlated with increases in the volume of fumarole emissions in the crater. No carbon dioxide was detected when measurements were made during 8-14 August.

Source: Instituto Geofisico-Escuela Politecnica Nacional