3D dynamic earthquake rupture modeling for the Hellenic Arc and implications for tsunami generation

The Hellenic Arc is an active seismogenic zone (Papadopoulos et al., 2010) yet characterized by a relatively low convergence rate. It hosted at least two M8 earthquakes, sourcing devastating tsunamis (Guidoboni et al. 1994) in the Mediterranean area. This low-angle interface is expected to trigger shallow slip amplification (e.g., Bilek and Lay 2018) and to cause large amounts of seafloor displacement. Long-term seismic-probabilistic tsunami hazard assessment (S-PTHA) and early warning systems typically make use of kinematic models to calculate static seafloor displacements which are then used as sources for tsunami models (Okada, 1985, Scala et al., 2020). The usage of mechanically consistent dynamic rupture models of generic megathrust settings can provide building blocks toward using physics-based dynamic rupture modeling in Probabilistic Tsunami Hazard Analysis (Wirp et al., 21). Here, we model a range of 3D subduction earthquake dynamic rupture scenarios in the Hellenic Arc, which we vary in terms of hypocenter location, magnitude, rupture speed, and shallow fault slip. Besides, we will model a tsunami earthquake that differs in rupture speed, peak slip rates, shallow slip amplification, and fracture energy compared to common subduction events. The modeling area covers the eastern Mediterranean and uses the slab geometry from the European Database of Seismogenic Faults (EDSF, Basili et al., 2013). The initial conditions in the 3D dynamic rupture model are constrained on the subduction zone scale (Ulrich et al., 2020) and specified for the Hellenic Arc region. We will next explore a novel 3D fully coupled earthquake-tsunami modeling approach by adding a water layer of variable depth and simulating earthquake dynamics, acoustic waves, and tsunamis simultaneously by accounting for compressibility, gravity, and elasticity (Lotto and Dunham, 2018; Krenz et al., 2021). The fully coupled model captures the dynamics of the entire tsunami-genesis in a single simulation, beyond approximations typical for standard earthquake-tsunami coupling workflows. We envision that mechanically consistent dynamic models can provide building blocks toward combined, self-consistent and physics-based Seismic and Tsunami Hazard Analysis.