Our most recent reports on Colima (BGVN 33:04 and 33:10) discussed new dome growth between February 2007 and November 2008. This report provides an update on the dome growth through May 2009.

According to a report from the Colima Observatory, the slow growth of Colima's new lava dome continued (figure 90). By March 2009, the volume was about 1,400,000 m³, roughly 80% of the total crater volume. Since the beginning of October 2007 the mean effusion rate has been ~ 0.03 m³/s. During the last two years, dome growth has been accompanied by 5-10 small explosions daily without significant variations (figure 91).

Figure 90. Dome volume versus time at Colima during January 2007 to March 2009. Courtesy of Colima Volcano Observatory.

Figure 91. A typical daily seismogram at Colima, showing small explosions during 1800 hours on 28 February to 1800 hours on 29 February 2009. Recorded at station EZV4, located 1.7 km from the crater; vertical lines are 1-minute intervals. Courtesy of Colima Volcano Observatory.

To improve monitoring of the dome growth and any lava flows, pyroclastic flows, and explosive columns, the video station Nevado has been upgraded with two additional video cameras. These cameras allow digital images of the crater and the whole volcanic edifice of Colima to be taken every 4 seconds (figure 92). The station is situated at ~ 4,000 m elevation, below the summit of Nevado de Colima and 5.8 km N of the Volcán de Colima crater.

Figure 92. Photos of Colima showing the edifice (top) and close-up of the crater (bottom). View is from the Nevado video station on 25 March 2009. Courtesy of Colima Volcano Observatory.

Table 18 contains a condensation of reports on Colima ash plumes and selected eruptions during 4 January 2006 though 25 May 2009.

Table 18. Ash plumes from Colima seen between 4 January 2006 and May 2009. The plume altitudes (height above mean sea level) are approximate and indicate the highest plume during the specified period. Incandescent ejections are meters above the summit. Data from the Washington Volcanic Ash Advisory Center, Universidad de Colima, Gobierno del Estado de Colima, and news articles.

Geological Summary. The Colima complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the high point of the complex) on the north and the historically active Volcán de Colima at the south. A group of late-Pleistocene cinder cones is located on the floor of the Colima graben west and east of the complex. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide scarp, breached to the south, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, producing thick debris-avalanche deposits on three sides of the complex. Frequent recorded eruptions date back to the 16th century. Occasional major explosive eruptions have destroyed the summit (most recently in 1913) and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.

Information Contacts: Observatorio Vulcanológico de la Universidad de Colima, Colima, Col., 28045, México (URL: https://portal.ucol.mx/cueiv/); Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/); Gobierno del Estado de Colima (URL: http://www.colima-estado.gob.mx/2006/index.php).