Seismic Imaging of the Remnant Southern Crater Wall of the Yilan Crater via Integrated Analysis of Seismic Surface Waves and First Arrivals

Abstract

The Yilan impact crater in northeastern China is generally well preserved, except for a ∼2 km gap along its southern rim. To investigate the structural disturbances recorded beneath the remnant southern crater wall, we conducted a shallow‐seismic survey in the southern part of the Yilan crater. We constructed the S‐wave and P‐wave velocity models by inverting the surface‐wave dispersion curves and first‐arrival travel times individually. K‐means clustering was applied to the multi‐parameter velocity models to transform the geophysical attributes into a zonation of the shallow subsurface that shows lithological variations. By comparing the clustered model with the extrapolated rim topography estimated by its preserved part on the Earth's surface, we found that the fractured bedrock of the remnant southern crater wall lies buried beneath more than 10 m of loose sediments. This indicates that the southern part of the crater wall has been significantly eroded and covered by sediments but still exists. It also shows that the farther away the rim is from its surface pinching point, the stronger the erosion and sedimentation have been. Overall, this study demonstrates the effectiveness of combining multiple seismic approaches with statistical clustering for structural delineation of the remnant southern crater wall buried below the Earth's surface and provides new geophysical evidence on the deformation of the Yilan crater.