Automatic Detection of Terrain Surface Changes After Wenchuan Earthquake, May 2008, From ALOS SAR Images Using 2EM-MRF Method

A method of two-threshold expectation maximum and Markov random field is presented to automatic detection of terrain surface changes after the Wenchuan earthquake, on May 12, 2008, using multitemporal ALOS PALSAR images. As an example in the Beichuan area, three kinds of terrain surface changes, i.e., scattering enhanced, reduced, and no-changed, are automatically detected and classified. By using the tool of Google Earth, the surface change situation after the earthquake can be shown in multiazimuth views as an animated cartoon. The detection and classification are also compared with optical photographs.