Radiocarbon ages for the timing of debris avalanches at Mombacho Volcano, Nicaragua

Abstract

Radiocarbon-dated lake sediments provide minimum-limiting ages for two major debris avalanches originating from Mombacho Volcano in Nicaragua. A basal age from Lake El Gancho indicates that the northeast debris avalanche (Las Isletas) occurred sometime before ∼140 to 345 A.D. Basal ages from Lakes Blanca and Verde indicate that the southern (El Crater) debris avalanche occurred sometime before ∼270 to 650 A.D. Both events therefore occurred in the space of a few centuries, yet there is strong evidence that the mechanisms varied for destabilization of each flank. Possibly, the influence of a developing hydrothermal system lead first to deeper structural failure in the substrata to produce the Las Isletas sector collapse, progressing to higher level destabilization within the edifice and the El Crater collapse.