Hellenic Arc tsunami generation from Mw8+ 3D margin-wide dynamic rupture earthquake scenarios

Sara Aniko Wirp, Fabian Kutschera , Alice-Agnes Gabriel , Thomas Ulrich , Michael Bader, Stefano Lorito

The Hellenic Arc subduction zone is the most seismically active region in the Mediterranean, capable of generating large earthquakes and tsunami.
Given the proximity of densely populated coastlines, understanding the characteristics of potential future large tsunamigenic earthquakes is crucial for assessing tsunami hazard.
We present non-linear shallow water tsunami simulations sourced from the static seafloor displacements of five Mw8-9 dynamic rupture earthquake scenarios along the Hellenic Arc, varying in hypocentral location, rupture extent, and moment magnitude.
In three of these 3D rupture models, slip penetrates the shallow slip-strengthening region of the megathrust, generating uplift patterns modulated by the location of the hypocenter.
Our results show that shallow slip and off-fault plastic deformation control the vertical near-trench uplift and tsunami height in the near-field.
Maximum tsunami amplitudes reach up to $\sim$6.6~m near central and eastern Mediterranean coastlines, while the northern Aegean and the western Mediterranean remain mostly shielded by landmasses in all scenarios.
One scenario is further extended into a large-scale fully-coupled 3D earthquake-tsunami model, capturing dynamic rupture, seismic and acoustic wave propagation, and time-dependent tsunami generation.
The fully-coupled simulation reveals complex interactions between acoustic and tsunami waves during the early generation phase, including dispersion and wave conversions between seismic and ocean acoustic waves not captured by static or linked models.
These results highlight the value of integrating 3D dynamic rupture modeling with tsunami simulations, enhance our understanding of tsunami generation mechanisms, and can provide physics-based insights to tsunami hazard assessment and early warning strategies.