Earthquake-induced sinkholes in Calabria

The attention on sinkholes phenomena has greatly increased in the last years, in the aftermath of the many events that have affected built-up areas in Italy and abroad. This has brought to a wider use of the term sinkholes, that is nowadays used also for events related to anthropogenic cavities, and/or to phenomena linked to occurrence of earthquakes. At this latter regard, the investigation of the surface effects triggered by seismic activity often poses some problems in discriminating between liquefaction phenomena and occurrence of sinkholes in alluvial plains. Especially when historical sources are examined, the descriptions and reports are typically similar, and when field evidence of the phenomena are no more recognizable, distinguishing one phenomenon from the other may be actually impossible. Starting from the above assumption, the contribution presents an analysis of the events induced by earthquakes in Calabria, for which historical documentation has been found. Among the case studies, worth to be mentioned is the 1783 seismic sequence, that struck central-southern Calabria and produced remarkable effects at the surface. A critical scrutiny of the available historical documentation is presented, integrated with description of the main geological and morphological features of the affected areas, in the attempt to identify seismically-triggered sinkholes, and to perform a preliminary analysis of the relationships between seismic parameters (magnitude, intensity, epicentral distance) and sinkholes.