Lateral variation in Moho depth around the southern Tanlu fault zone and its adjacent area

We estimated Moho depth beneath the southern Tanlu fault zone and its adjacent area using common-conversion-point (CCP) stacking of receiver functions, which were computed from teleseismic records of the CEArray. Our estimated Moho depth matches well with 2-D profiles derived from active-source deep seismic reflection surveys, suggesting that the calculated the Moho depth map is likely accurate beyond the 2-D profiles. Overall, the estimated Moho depth map showed a high spatial correlation with tectonic provinces, i.e., Moho topographic boundaries are in good agreement with geological boundaries. Beneath the Dabie orogenic belt and the mountainous areas in southern Anhui Province, the Moho lies relatively deep, and there is an obvious difference in Moho depth between the two sides of this segment of the Tanlu fault. We further selected four depth profiles with dense instrumentation to show Moho depth changes across different tectonic blocks in the study area. We saw two step-like changes in Moho depth beneath the Xiangfan-Guangji and Gushi-Feizhong, which run parallel along the WNW-ESE direction and delineate the southern and northern bounds of the northern Dabie orogenic belt, which is likely the suture zone between the North China Block and South China Block. Crust beneath the northeast corner of the study area is significantly thinner than other areas, which is consistent with the crustal detachment model proposed for suturing between the North and South China blocks in the region east to the Tanlu fault.