The antique Sparta Earthquake (Peloponnesus, Greece) and Limestone Scarps on Active Faults: a Field Guide

Abstract

The 464 BCE Sparta earthquake (Greece) is one of the main historically documented seismic events in the Mediterranean, yet its tectonic source and magnitude remained unknown until the 1990’s. This field guide synthesizes historical accounts and integrates field observations with seminal works (Armijo et al., 1991, 1992; Benedetti et al., 2002) to assess the seismotectonic context of the Sparta Fault, a prominent normal fault bounding the Taygetus mountain range (highest mountain of the Peloponnesus). Along the fault, and at the base of spectacular triangular facets, a steep 10 m high limestone scarp points to repeated surface-rupturing earthquakes. Field observations and cosmogenic dating (Benedetti et al., 2002) show that the scarp formed through the accumulation of at least 4 to 5 Holocene earthquakes with ~2 m displacement, the most recent one being the 464 BCE event. We detail a series of field stops, progressing from large-scale panoramic views of the fault system to close-up observations of the scarp itself. We conclude by outlining the field-based discussions that can be conducted with participants to the excursion regarding the interactions between fault activity, climate-driven landscape evolution, and seismic hazard assessment.