A cluster of earthquakes that had been recorded at Cayambe since 16 September, with about 300 small earthquakes occurring during 16-18 September, decreased in number significantly after 19 September. During 19-25 September, an average of 5.3 earthquakes occurred daily.

All times are local (= UTC - 9 hours [or 8 hours early April-late October])

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

---

28 September 2005            Back to Top

A cluster of earthquakes that had been recorded at Cayambe since 16 September, with about 300 small earthquakes occurring during 16-18 September, decreased in number significantly after 19 September. During 19-25 September, an average of 5.3 earthquakes occurred daily.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)

---

14 September 2005            Back to Top

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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)

---

18 February 2004            Back to Top

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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)

---

12 November 2003            Back to Top

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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)

---

Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Beate B, 1992. . (pers. comm.)

Hall M L, 1992. . (pers. comm.)

Hall M L, 1977. {El Volcanismo en El Ecuador}. Quito: Biblioteca Ecuador, 120 p

Hall M L, Mothes P A, 2008b. Volcanic impediments in the progressive development of pre-Columbian civilizations in the Ecuadorian Andes. {J Volc Geotherm Res}, 176: 344-355

Le Pennec J-L, Ruiz-P A G, 2006. Late Pleistocene to Holocene activity of Imbabura volcano. {Cities on Volcanoes 4, Quito, Ecuador, 23-27 Jan, 2006}, Field trip C2: 1-8

Imbabura volcano rises to the north above scenic Laguna de San Pablo in the Interandean valley about 60 km north of Quito. The main edifice, Taita Imbabura ("Father Imbabura") forms the summit, with Huarmi Imbabura ("Imbabura's Son") forming a lateral lava-dome complex on the SW flank. Activity at the Pleistocene Imbabura I edifice constructed a large andesitic stratovolcano and ended prior to about 43,000 years ago with a major collapse that produced a debris avalanche that traveled 16 km to the north. Subsequent growth of the Imbabura II stratovolcano continued at least into the early Holocene and typically consisted of growth and collapse of large-volume dacitic lava domes. A major eruption about 25,000 years ago produced a debris avalanche and possible lateral blast and was followed by growth of the Huarmi Imbabura lava dome. Historical reports of eruptions consisted of only mudflows and rock slides.