Late Roman–Early Byzantine Leukos settlement, Karpathos, Greece: Geoarchaeology, archeoseismology, and paleogeography

This archeoseismologic study focuses on the Leukos settlement that thrived on the west coast of the forearc island of Karpathos in the 4th−6th centuries CE. The onshore site occupies the eastern rim of the offshore Karpathos Basin, the deepest Aegean basin, in a sector of the Hellenic forearc typically regarded as seismically insignificant. Investigations of faulting, sedimentary processes, and secondary earthquake effects (hydraulic fracturing, liquefaction, tilting, landslides) are integrated with observations of previously surveyed and newly discovered archeological remains to appraise syn- to post-Early Byzantine seismicity and establish a sequence of faulting. Calibrated radiocarbon dates, the first from Karpathos, indicate intermittent faulting and seismicity spanning the 4th−10th centuries CE, likely contributing to the early 7th-century CE abandonment of Leukos. The coseismic rupture of competent cobbles whose fractures are filled with fluidized sediment is an established paleoseismologic tool for recognizing earthquakes of magnitude M_w ≥ 6; this study extends that criterion to archeoseismology. This study underscores the need to evaluate land movements, sea-level fluctuations, and shoreline migration for coastal archeological sites. A plausible Late Roman paleogeography emerges in which Leukos occupied a contiguous peninsula rather than surrounding three modern harbors. This study encourages re-evaluation of seismic and tsunami hazards in the sector of the Hellenic forearc surrounding ancient Leukos and the Karpathos Basin.