Interpretation of gravity-seismic joint inversion and its application in Longmenshan region

• Edge detection and Euler deconvolution to invert the gravity anomalies. • The fault distribution characteristics and the approximate depth of fault tops. • Morphology difference and possible earthquake formation have been analyzed. • 2-D interactive joint inversion based on the existing seismic and gravity data. • The subsurface structure and the earthquake formation mechanism was discussed. Analysis and research of large complex phenomena before and after the devastating earthquake is of great significance to reduce the threat of natural disasters. Understanding the complex structural deformation of the Longmenshan Fault Zone is essential for elucidating crustal deformation and seismic dynamic mechanisms. This paper analyzes the gravity anomaly distribution characteristics in the Wenchuan Earthquake zone, and subsequently applies edge detection method to invert the pre-earthquake gravity anomalies of the Longmenshan region. The fault distribution characteristics in the Longmenshan region and its adjacent areas before the earthquake have been determined. Besides, morphology difference and possible earthquake formation have been analyzed through the Euler deconvolution results of gravity anomaly profile before and after the earthquake. Finally, a 2-D interactive joint inversion was performed based on the existing seismic and gravity data. The subsurface structure was revealed, and the earthquake formation mechanism was discussed by comparing the underground changes before and after the event.