Potentially tsunamigenic layer in late Holocene Great South Bay, Long Island, New York: constraints on origins, processes, and effects

Abstract

Sediment core and seismic data was collected and analyzed in order to study the late Holocene geologic history in the Great South Bay estuary, Long Island, New York. The data reveals a distinct and anomalous deposit whose sedimentological characteristics and distribution are shown to be consistent with a modest tsunami striking the New York and New Jersey coast between 2200 and 2400 yr BP. In addition, core and radiocarbon date information are used to reconstruct the chronostratigraphy of the estuary during this period. The timing of the tsunami event coincides with an abrupt transition into the modern estuarine depositional regime of the bay. Such a sudden shift in depositional patterns had not been seen prior and has not been seen since. With significant human population and real estate located in the region, the stability and susceptibility to potentially recurring events is a prompt for understanding such influences or response of the modern coastal system.