Direct inversion of surface wave dispersion data with multiple-grid parametrizations and its application to a dense array in Chao Lake, eastern China

• DOI: 10.1093/gji/ggab036
• Publication Date: 2021-01-22T23:20:25Z
• Authors: Song Luo; Huajian Yao; Jiannan Wang; Kangdong Wang; Bin Liu
• Keywords: Parametrization (atmospheric modeling); Interpolation

SUMMARY The direct surface wave tomography has become an efficient tool in imaging 3-D shallow Earth structure. However, some fundamental problems still exist selecting the grids to parametrize model space. This study proposes implement a parametrization approach with multiple tomography. These represent several overlapping collocated same or different grid spacings, such as staggered grids, multiscale and multiscale-staggered grids. At each iteration, inversion is applied individual set of invert for shear velocity (Vs) model; models are then projected onto predefined base (usually finest grids) using B-spline interpolation. end we average Vs all sets obtain model, which used initial next iteration. properties this explored by applying it newly deployed dense array Chao Lake (CL), eastern China. Synthetic field data tests demonstrate that method recovers anomaly patterns better than though does not necessarily achieve smallest traveltime residual. We high-resolution crustal beneath CL. reveals two prominent features: (1) stripe-like structural pattern variations, where Hefei basin CL display low-velocity anomalies while Tanlu fault zone (TFZ), Zhangbaling uplift Yinping mountain present high-velocity (2) north-shifted depths go shallow. features consistent well local geological units topography. suggest main could be associated multistage tectonic activities fault. multiple-grid scheme proposed conveniently extended other approaches near future.