GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.3 ______ ___ GNGTS 2023 Evaluation of straight-ray and curved-ray surface wave tomography at near-surface scale: A 3D numerical example M. Karimpour 1 , E. Slob 2 , L. V. Socco 1 1 Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Turin, Italy 2 Department of Geoscience and Engineering, Delft University of Technology, Delft, Netherlands Introduction Surface wave tomography (SWT) is a method that has been used to model the Earth’s crust and mantle in seismological studies. SWT has recently become popular in near-surface studies (e.g., Rector et al., 2015; Ikeda and Tsuji, 2020) because of its ability to provide high lateral resolution. In some of the SWT near-surface studies it is assumed that surface waves propagate along a straight line between the source and the receiver. However, this assumption might not be valid in the complex near-surface structures. Curved-ray SWT is an alternative approach where the path of each frequency component of the DC is computed. It seems important to investigate the gained model improvement together with the associated additional computational cost from curved-ray over straight-ray SWT for near-surface applications. In this work, we apply straight-ray and curved-ray SWT to a 3D numerical example and compare the results in terms of accuracy and computational cost. Method The calculation of the forward response is different in the straight-ray and curved-ray SWT approaches. In curved-ray SWT, first the actual ray path between the receiver pair for each frequency component of the DC is computed. Then the forward response (i.e., simulated DCs) is computed as: (1)