Abstract: In this paper, we introduce the method by using co-seismic displacement to calculate seismic intensity as applied to Haiti M7.3 earthquake and Wenchuan M8.0 earthquake examples. Under the condition of knowing the three elements of earthquake, fault strike, dip and slip direction, we could determine the distribution of seismic intensity by calculating the absolute co-seismic displacement. This study shows that intensity distribution map calculated by the absolute co-seismic displacement is in good agreement with the actual seismic intensity map, especially in the highly seismic area the results corresponds better. While such calculations are sometimes combined with a certain access to the actual situation, it would play an important role in rapid disaster assessment and relief dicision-making after earthquakes. In particular, this method has a more unique advantage in the region where strong seismic stations are sparse and in the case of not getting timely information and data shortly after a large earthquake.

Key words: Three elements of earthquake, Fault parameter, Co-seismic deformation, Seismic intensity