AIC analysis of categorizing data for earthquakes and velocity structures in North China

The relation between the occurrence of strong earthquakes and the tomographic velocity structure in North China is quantitatively analyzed by using the AIC analysis method for categorical data. The results indicate that the areas of low P-wave velocity in the lower crust and the top of upper mantle and areas of high S-wave horizontal gradient in the upper and lower crust are correlated with earthquakes of magnitude greater than 5–6. The correlation may be related to the geodynamics of Cenozoic thinning of the lithosphere and upwelling of mantle materials. The lateral inhomogeneous zones in crustal structure and thermal state are prone to occur strong earthquakes. This subject is sponsored by the key project during the “9th Five Year Plan” from the China Seismological Bureau (9504030301) and the State Natural Science Foundation of China.