Anatomy of the February 6, 2023, eastern Mediterranean tsunami: Field observations, sea level analysis and numerical modeling

On February 6, 2023, two strong earthquakes with magnitudes Mw 7.8 and Mw 7.5 struck southeastern Turkiye, causing widespread structural damage and loss of life. An unexpected tsunami was observed in the Eastern Mediterranean following the first earthquake, despite the rupture occurring onshore. This study investigates the tsunami source mechanism, hypothesizing submarine landslides generated the waves recorded at five tide gauges. We integrate field survey observations, sea level analysis and numerical simulations to estimate the location, dimensions and orientation of the tsunami source(s). Surveys along the Gulf of Iskenderun revealed pronounced sea level fluctuations, including a 0.55 m tsunami run-up and similar to 65 m inundation in Samandag-Cevlik. Our findings suggest a submarine landslide source similar to 20 km x 14 km in size, with +/- 1.0 m initial amplitude and an estimated volume of 0.163 km(3). The numerical simulations successfully reproduce observed tsunami amplitudes and survey data, confirming that a submarine landslide is a plausible cause. Furthermore, our analysis highlights the strong sensitivity to landslide orientation and a nearly linear relationship between initial amplitude and maximum sea level response. Our findings contribute to improved tsunami early warning systems by incorporating atypical tsunami sources, enhancing hazard mitigation, and guiding future undersea investigations in the region.