Shear-Wave Velocity Model for the Dead Sea Transform from Multimode Inversion of Surface Waves Excited by the February 2023 Southeast Türkiye Earthquake Sequence

Abstract

Abstract The dispersive nature of surface waves can be used for shear-wave velocity inversion at different scales. We show that four large earthquakes from the 2023 Türkiye earthquake sequence generate visible surface waves recorded by a dense strong-motion network deployed along the Dead Sea Transform (DST) in Israel. Thanks to favorable geometrical conditions and source radiation patterns, we observe both Rayleigh and Love waves that travel predominantly parallel to the network. We can reliably compute the dispersion of three Love-wave modes and two Rayleigh-wave modes. Using these dispersion curves, we invert for a 1D S-wave velocity model of the entire DST, outperforming an existing model. Statistical and kernel sensitivity analysis show high certainty down to a depth of 30 km thanks to the multimode joint inversion in the frequency band of 0.03–0.3 Hz. Using a multiwindow approach, we invert for an along-strike laterally varying velocity model of the DST. Although it is limited to the fundamental Love-wave mode, using the 1D model as a constraint allows us to recover a shallow (10 km) velocity structure in agreement with previous studies of the area. Despite the simplicity of our used approach, it can be used as a basis for more advanced studies.