Reconocimiento geológico y evaluación preliminar de peligrosidad del volcán Tacaná, Guatemala/México

Abstract

Tacaná Volcano, Guatemala/México is the volcano at the northwestern end of the Central American volcanic belt. It has erupted silicic andesites of calc-alkalic affmity and moderate K-enrichment. Tacaná has no record of magmatic eruptive activity in historic times, but has shown a panern of brief periods of fumarolic and phreatic activity spaced one quarter to half a century aparto The latest started on December 1985 and continued at the time of preparation of this paper (1988). Small eruptions occurred in February, May and June 1986. Analysis of ashes indicates that the three eruptions were phreatic. Magmatic activity is likely in the future and may follow scenarios based on similar volcanoes (Arenal, Santa María, Sto Helens) and result in considerable hazards. A photogeologic map and two volcanic hazard maps are presented. Ash dispersal will be influenced by the seasonal dependence on prevailing winds in Guatemala.