Megalandslide (<i>debris avalanche?</i>) in the north flank of Cacahuatique volcano, Morazan, El Salvador

Abstract

A mega landslide, a probably debris avalanche type, affecting the north flank of Cacahuatique volcano in Morazán, El Salvador, is described in this paper. An estimated 6000 MCM (Million Cubic Meters) of volcanic materials slide from the northern slopes of Cacahuatique volcano to the Torola River left bank. The main landslide is 6 km wide by 5 km long and at least 200 m thick to produce a debris flow probably during late Pliocene to early Pleistocene. Most of the original landslide materials have been eroded by Los Reyes, Gualpuca, Grande and Torola rivers but some relicts still remain in the flow area like Cerro San Lucas (hummocky morphology).Geomorphologic and geological data are described to support the thesis of the mega landslide occurrence.