Exploring the relationship between InSAR coseismic deformation and earthquake-damaged buildings

Abstract Strong ground vibration triggered by seismic waves is one of the most significant factors that causes building damage during a seismic event. The interferometric synthetic aperture radar (InSAR) technique can efficiently and quickly provide seismic deformation information. There is no clear relationship model between seismic deformation and the degree of building damage. Considering the earthquake that hit Wenchuan (China) on May 12, 2008, in this work, a method to evaluate the degree of building damage based on coseismic deformation is presented. Based on 51 building area samples selected, taking the Deformation normalization index(DNI) as the independent variable and the earthquake damage index (EDI) of the field survey data provided by the China Earthquake Administration (CEA) as the dependent variable, the relationships between seismic damage survey data and the seismic deformation of adobe structures, brick-wood structures, brick-concrete structures and reinforced concrete frame structures are analysed. There are linear relationships between the normalized deformation indices of adobe and brick-concrete structure types and the EDIs of buildings. There are quadratic relationships between the normalized seismic deformation indices of brick-wood structures and reinforced concrete frame construction types and the EDIs of buildings. Additionally, the regional curve estimates of the comprehensive building damage index and the normalized index of seismic deformation show that there is a quadratic relationship between the comprehensive building damage index and the normalized index of seismic deformation. The validity of the modelling method was verified by data from the Yushu earthquake in 2010. The results can provide an accurate and reliable reference basis for post-earthquake rescue and decision making. The work represents a new concept and method for the rapid assessment of building damage data from the perspective of surface deformation movement by addressing methodological steps, highlighting the potential of using the coseismic deformation field obtained during building damage assessment, and discussing the potential and limitations of InSAR technology in the field of damage detection.