Volcanism, Ecology and Culture: A Reassessment of the Volcán Ilopango TBJ Eruption in the Southern Maya Realm

Abstract

The Tierra Blanca Joven (TBJ) eruption of the Ilopango caldera in central El Salvador was one of the largest Holocene volcanic events in Central America, and its ecological and cultural impacts were felt throughout El Salvador and adjoining areas of Guatemala and Honduras. Early radiocarbon measurements established a ca. A. D. 260 ± 114 calendar date for the eruption. However, a reevaluation of the original 14C dates, in addition to new AMS 14C assays, shows that the TBJ eruption occurred at least a century and a half later than originally estimated. The revised 14C composite supports an Early Classic Period calendar date for the eruption: 1 sigma = A. D. 421(429)526; 2 sigma = A. D. 408(429)536. A review of archaeological settlement, ceramic, and radiocarbon evidence from sites throughout the area of greatest devastation reveals a large-scale demographic collapse following the event. We believe that the population crash was caused both by the biophysical effects of the eruption and by the resulting disarticulation of the "Miraflores" cultural-economic sphere. The affected areas of El Salvador and south-eastern Guatemala did not completely recover until the seventh century A. D.