Abstract: There are some different explanations for the inclination origin of the south and north pagodas of the Three Pagodas in the Chongsheng Temple, Dali. Based on detailed site engineering geological survey and laboratory tests, combining the regional geological background and historical literatures analysis, it is presented that the main reason for the inclination of the two towers is earthquake rather than the nonuniformity of ground soils according to foundation settlement calculation and seismic simulation. The whipping effect derived from seismic action of the pagodas is significant which has caused several times top destruction in history. The vertical compressive forces at bottom layer fluctuate greatly during earthquake but it is safe comparing with the ultimate strengthen of brick masonry. Tension forces take place obviously at the middle part which cause fractures in case of high seismic magnitude. It is considerably reduced by the silt clay under the pagodas foundation that the propagation of earthquake wave from ground and the effect of the seismic vibration.

Key words: Dali Three Pagodas, inclination, earthquake