Recovering a lost seismic disaster. The destruction of El Castillejo and the discovery of the earliest historic earthquake affecting the Granada region (Spain)

This paper discusses recent archaeological fieldwork conducted at El Castillejo, a medieval Islamic settlement in Los Gua´ jares, Granada, southern Spain. Results from combined archaeological excavation and archaeoseismological assessment of standing structures suggest that the site was affected by a destructive earthquake during its occupation. Radiocarbon samples and OSL analysis point to a seismic event in the period CE 1224–1266. The earthquake occurred within an area marked by a ‘seismological gap’ in terms of historic seismicity and the causative fault has been tentatively identified in the Nigu¨elas-Padul Fault System which lies north of the settlement. This event is not recorded by national or European seismic catalogues and represents the oldest historic earthquake in the Granada area. Our work stresses the significant impact that targeted archaeological investigations can generate in our understanding of the local historic seismicity, thus providing clear implications for seismic disaster prevention and reduction.