Shallow Offshore Tsunami Sedimentary Deposits: Challenges and Benefits with examples from the Eastern Mediterranean and northern Red Sea

Abstract:

Tsunamigenic deposits preserved in the offshore, shallow (<30msl) uppershelf environment has been suggested as a possible resource for improving the understanding of tsunami sedimentological dynamics and producing a more detailed paleotsunami record. On one hand, this zone is advantageous due to its relatively lower susceptibility to anthropogenic disturbance and certain types of erosion. However, the added complications of collection difficulties, marine dynamics and disturbance, and heterogeneity may prove this archive less desirable and accessible. Recent results of a multitude of offshore shallow coring efforts in the eastern Mediterranean and northern Red Sea will be presented and discussed with regard to the question of the usefulness, limitations, and advantages of these offshore records. Broadly summarized, like their terrestrial counterparts, the offshore archive requires extensive attention to the local background conditions and characteristics of the surrounding contributing sources in order to recognize, interpret, and mine the information contained within them. While some tsunami indicator criteria remain the ‘rule’, their expression and appearance inter and intrasite can vary considerably and therefore the ability to recognize them challenging. Ultimately, as more results are shared from recent modern analogues and compared with sedimentological anomalies with possible tsunamigenic characteristics within the offshore sedimentological record, the better and more precisely these deposits will be defined and interpreted.