Investigating the Geological Fault Framework Offshore Lebanon: Insight into the Earthquake Geology of the Eastern Mediterranean Region

Abstract

The tectonic setting of Lebanon in the eastern Mediterranean region is a restraining bend along the Dead Sea Transform Fault, which is the plate boundary between Arabia and Africa. Within the Lebanese Restraining Bend, the plate boundary splays into several fault branches that are mapped onshore Lebanon and known to have contributed to the evolution of the Lebanese structural framework. Different models have been proposed about the geological structures offshore Lebanon, and how those structures could relate to the onshore tectonics. Based on 2D seismic reflection data, a previously interpreted thrust fault system offshore Lebanon referred to as “Mount Lebanon thrust” was suggested to be responsible for the 9 July 551 M 7.2 earthquake, which was one of the most destructive in the history of the Levant. This thrust system has been accepted as the main structure behind the offshore seismic activity. The objective of this paper is to use current 3D seismic reflection data in order to interpret the main tectonic structures offshore Lebanon, and to differentiate features formed by tectonic activity from others caused by different mechanisms such as subsurface salt movement. Such information is very useful in understanding the tectonic framework of the region from the earthquake geology perspective. A bathymetric map of the Lebanese offshore area was generated and used to delineate the seafloor features. Major and minor faults were interpreted and used to identify and understand the behavior of potential tsunami-generating structures. After careful investigation of the offshore area using the available 3D seismic data, the authors were not able to confirm the existence of Mount Lebanon thrust. Instead, they propose that the Latakia ridge that lies between Lebanon and Cyprus is a major and prominent structure that can trigger high-magnitude tsunamigenic earthquakes. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.