Rapid Assessment of High Seismic Intensity Areas of the 2008 Mw 7.9 Wenchuan Earthquake Using Satellite SAR Data

This paper proposed the novel method of rapidly assessing highseismic-intensity areas by using satellite geodetic surveys. We recompute pixel displacements using ALOS/PALSAR data for the Wenchuan earthquake and densely distribute them across the area as profiles. Our profiles provide detailed information of areas within higher seismic intensity contours, especially for high mountainous areas for which limited information was available. Vast amounts of field investigations provide valuable supplementary information about field fault scarps, landslides, and seismic intensity contours. By analyses of displacements and seismic intensity contours, we propose a displacement-to-intensity criterion to qualitatively judge if high seismic intensity has occurred. Displacements of ≥ 1 m may correspond to areas where higher intensities has occurred (> IX), and displacements of < 1 m may relate to areas where intensity < VIII has occurred. We reveal that seismic intensity IX extended into intensity VIII areas in western mountainous regions based on the criterion. Following mega (i.e., > M w 7) inland earthquakes, ground displacements of > 1 m may indicate the possibility that the area suffers from high seismic intensities.