This article presents stratigraphic data and radiocarbon dates combined with Bayesian modeling from San Andrés in the Zapotitán Valley, El Salvador, focusing on the Campana Structure, the largest and longest-used monumental structure at the site. These data refine the regional chronology of the valley and provide insights into the emergence, development, and abandonment of this pivotal center in southeastern Mesoamerica and its potential links to three related volcanic eruptions: Ilopango, Loma Caldera, and El Boquerón. These distinct volcanic events had pronounced effects on local people who innovated new monumental construction projects and used new volcanic debris as construction material after major eruptions. It is suggested that these monumental public building projects played an important role in the post-disaster recovery of societies by helping foster a sense of corporate identity. The use of volcanic material in constructions at San Andrés and the building of these massive structures may also have helped keep these events alive in the communal memory.
