The physical and geochemical characteristics of ash and ash leachates and their incorporation in dynamic models of activity

Samples of ash are being collected whenever possible after explosive events at Volcán de Colima. A quantity of the ash is processed to remove the leachates which are then analyzed for major ions. Another portion of the ash is examined under the microscope to determine the relative proportions of different products (lithics, glass and minerals), identify the minerals present and observe the vesicularity and morphology of the particles.

The leachates can provide an indication of the relative abundance of SO2, HF and HCl in the volcanic plume. Due to their different solubilities in magma, this can indicate whether a magma body is rising or descending in the conduit.

The physical characteristics of the ash can provide information on the depth of the explosive event.

Dr. Juan Carlos Mora, Instituto de Geofísica, UNAM, Mexico
Ma. Antonia Carvajal García, Facultad de Ciencias Químicas, Universidad de Colima