Approach to Evaluating Seismic Intensity by Integrating InSAR Co-seismic Deformation and Far Field Observation Data

Abstract

Seismic intensity (SI) is an important reference index for understanding disaster situations, establishing emergency rescue plans and performing loss assessments after an earthquake. In this paper, we investigated the feasibility of assessing SI through interferometric synthetic aperture radar (InSAR) data after the Wenchuan earthquake on May 12, 2008, in China. The proposed approach relies on pre-existing residential data to obtain the regional seismic deformation corresponding to blocks. Theoretical maximum and minimum values analysis was carried out according to seismic attenuation relationships, and the deformation points were classified using Jenks natural breakpoints. The deformation field data were used to evaluate the epicenter and periphery areas. Instrument-based intensity values of stations were included in our analysis and used to investigate the periphery of the study area. Classification results of deformation field and instrument-based intensity values were combined to form a complete deformation field. The effectiveness of the method was verified based on a case study of the Yushu earthquake, another severe earthquake in China.The work represents one of the first attempts to establish the potential relationship between the seismic deformation field and intensity in China, validated against ground survey data. This study addresses methodological aspects, highlighting the potential of the co-seismic deformation field for intensity assessment, and discusses the limitations of terrain and data in this approach compared to ground surveys.