Offshore Tsunamigenic Deposits: Lessons from the past and present by Dr. Goodman

In the past two decades, major tsunami events have raised worldwide awareness of the hazards and risk related to tsunamis.  The standard for determining risk uses records of past events as a template for estimating future risk.  This is very effective in long-inhabited regions with well maintained histories, such as Japan.  However, areas that are only recently settled or without records can be falsely labeled as low-risk.  Physical sedimentological records from tsunamis are a means for identifying the signatures of past tsunamis whether there are or are not written records.  Today, as population is expanding worldwide, and the concentration of that population is disproportionately located on coastlines, reconstructing these records is becoming more critical for disaster preparedness and proper coastal management.  The number of studies describing and characterizing tsunami sediments has increased exponentially following the megatsunamis of 2004 (Indian Ocean), 2010 (Chile), and 2011 (Tōhoku). The knowledge gained from this research has improved the ability of sedimentologists to identify, interpret, and better model tsunami remains in older deposits. What has become particularly apparent is the rapid disruption and alteration of deposits along the coastline, both from deliberate anthropogenic activities (e.g. clean-up), and also from natural affects (erosion, run-off) makes dependence on terrestrial records alone precarious.  Studies offshore have shown great promise for the potential preservation of records in the marine realm.  A wide range of examples of both recent and ancient offshore tsunami signatures, including those associated to events that damaged the ancient harbor of Caesarea Maritima, will be shared and discussed.