Abstract: Studying the mechanical characteristics of the lithosphere in the areas where strong earthquakes have often happened are of significance for exploring the occurrence mechanisms of strong earthquakes. The lithosphere effective elastic thickness (T_e) and initial loading ratio (F) are closely related to the mechanical characteristics of the continental lithosphere. We use a new joint inversion method integrated both admittance and coherence techniques to compute the effective elastic thickness and initial loading ratio in the Chinese mainland, with the WGM2012 gravity data, ETOPO1 topographic data, and the data of Moho depth and crustal density from CRUST1.0 model. Based on the estimated T_e and F, we discuss that how the parameters of T_e, F, and gradients of them affect the environment for the development of strong earthquake. We find the high-degree earthquake tectonic areas tend to low T_e and high gradients of T_e and F. These suggest that the regions with a relatively low lithosphere strength, and those at the belts with sharp changes of lithosphere strength and internal load can provide a positive environment for developing strong earthquakes.

Key words: Lithosphere, Effective elastic thickness, Initial loading ratio, Earthquake distribution