Numerical Modelling of the Potential Hazard Due to Future Flores Back Arc Thrust Earthquake Generated Tsunami

Abstract Indonesia is situated at the conjunction of four major plates: Eurasia, India-Australia, the Pacific, and the Philippine Sea. Therefore, Indonesia is exposed to a considerable threat from natural hazards every day. Tectonic-related marine geohazards, particularly earthquakes-generated tsunamis periodically affect Indonesia, causing great loss of life and extensive damage to property and infrastructure in coastal areas. Many studies on tsunami modeling have been addressed in western Indonesia. In eastern Indonesia tsunamis, however, are even more frequent in occurrence and may be more hazardous, there is a lack of study and less attention. The Flores Back Arc Thrust (FBAT) is an active fault that lies on the sea floor of the Flores Sea in the north of Flores Island, extending from north of Bali to the east that may be connected to the Wetar thrust at the north of Wetar Island in the western Banda Sea. The FBAT is a source of seismicity in this area. From 1900 to 2022, there were 79 earthquakes with a magnitude of more than 6.0 Mw, and 11 of them generated tsunamis, and the most devastating one was the 1992 Flores earthquake tsunami. This study presents an estimated FBAT-induced future earthquake-generated tsunami runup based on numerical modeling.