The existence of volcano collapse deposits in Guatemala was first suggested by Rose et al. (1975) based on skylab photography; they identified two poorly vegetated fans south of Escuintla and south of Chiquimulilla as possible volcanic lahar fans. The results of this study show that the fan near Escuintla is entirely formed of a Pleistocene or lower Holocene debris avalanche and the fan near Chiquimulilla, of Holocene and Pleistocene alluvial fans. During a preliminary hazard assessment of Pacaya volcano, Banks (1986) noted the existence of a debris avalanche along Río Metapa (which drains SSW from Pacaya Volcano) and indicated Pacaya Volcano as its source. Our current work confirms this conclusion. In addition, we have outlined a third debris avalanche deposit, probably from Fuego Volcano, south of Siquinalá and west of La Democracia.
(Vallance et al., 1988)