V23A-3075
Comparison of Eruptive Processes of the years 1903 and 2015 of the Colima Volcano, Mexico.

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Carlos Suarez-Plascencia, University of Guadalajara, Geografia y Ordenacion Territorial, Puerto Vallarta, Mexico, Francisco J Nuñez-Cornu, University of Guadalajara, Puerto Vallarta, Mexico, Alfredo Hernandez-Rodriguez, Unidad Estatal de Proteccion Civil y Bomberos, Base Regional Ciudad Guzman, Guadalajara, Mexico and Bianca Valeria Suarez-Gonzalez, University of Guadalajara, Departamento de Biologia, Guadalajara, Mexico
Abstract:
The Colima volcano eruption processes during the months of January - July 2015, was characterized by two types of activity:
  1. From January to May we registered 923 exhalations and smaller explosions. Having up to 31 events per day, the columns of ash reached an altitude between 4500 and 7000 masl. Each event frequently averaging between 50 and 500 meters from about 442 or 48% of the total events this period. The reports of falling ash came from as far as the city of Salamanca at 278 km to the NE.

The intense activity destroyed the original dome forming a new one with an elliptical crater 224 m by 166 m and 35 m deep.

On May 15 we observed the growth of a new dome. On July 4, this created the falling of rocks along the slopes and the formation of three Andesitic lava flows at the N, SW and S flanks.

By July 11 the volume of lava extruded was about 6 x106 m3, with a rate extrusion of 1.21 m3per sec.

2. Based on three flyby observations, it was noted that the lava flows on the S and SW sectors had a higher extrusion rate in the N sector. The first two were placed on a slope with an average gradient of 36º, while on the northern slope gradient is 23º, as a result of the interaction of extrusion speed, slope and height of the lava front, there were constant landslides, causing at least 4 Merapi type pyroclastic flows, that flowed by the gullies of Montegrande and San Antonio. The first flow reached distances of 7 km and 10.4 km. It is the largest lava flow recorded since January 20, 1913.

The devastating results were the burning of 500 meters of the Templado Forest, burning along the Montegrande Creek and finally affecting many crops and livestock. This type of activity already had shown in 1975 and 1991 by the lava flow and S NE flank where the pyroclastic flows had no destructive effects, except for some small fires in forested areas at the base of the volcano (Thorpe, et al, 1977).

In March 1903 Colima volcano showed similar activity per Arreola J. and Diaz Severo, who reported a formation of an amphitheater opening to the E, while now on July 11, 2015 an amphitheater was formed towards the S sector.

The similarity in the evolution process of these eruptions allows us to frame the question: At the end of this fourth cycle of activity of Colima volcano, are we very close to a large subplinian or Plinian eruption such as it occurred in the years 1611, 1818 and 1913?

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