Research on Shallow Crustal Structure in the Beichuan Area with Short-Period Dense Seismic Array

Project Background: In 2008, the Wenchuan earthquake left numerous surface rupture zones in the old county town of Beichuan, making it susceptible to various geological hazards such as landslides and subsidence. Therefore, a short-period dense seismic array method was employed to investigate the subsurface structure of this area.

Equipment Used: 242 SmartSolo seismic node instruments.

Project Overview: This study employed a short-period dense seismic array to conduct background noise tomography and Horizontal-to-Vertical Spectral Ratio (HVSR) analysis in the Beichuan area. The research identified three low-velocity shear wave anomaly zones, one of which is located approximately 2 kilometers deep near the surface rupture zone of the Wenchuan earthquake. Stations near the surface rupture zone exhibited bimodal features in their HVSR curves, while those farther away from the rupture zone displayed unimodal characteristics. The maximum thickness of sedimentary layers in the study area was found to be up to 200 meters.