High-resolution crustal structure of Haicheng seismic zone in Liaoning, inferred from teleseismic receiver functions of dense array

The Haicheng seismic zone, crossing from the Xialiaohe Basin to Liaodong Uplift, is located in northern part of the Tanlu fault system. It has been delimited as high-risk seismic area in Chinese continent due to its intense seismicity. In this article, we construct high-resolution 3D crustal structure of the Haicheng seismic zone using the broadband seismic data from 23 newly distributed dense mobile array and the fixed Yingkou station in the area. Specifically, the H-kappa method and Common Converse Point (CCP) stack imaging are carried out using teleseismic P-wave receiver functions. Our results show that the regional crustal thickness is between 24.2 similar to 33.3 km with the crustal Possion ' s ratio ranging between 0.24 similar to 0.34. The Xialiaohe Basin on the west side of the area has a thin crust with a thinnest thickness of 24.2 km while the Liaodong Uplift on the east side is thicker with a maximum thickness of 33.3 km. The Moho has a smooth variation from the Xialiaohe Basin to the Liaodong Uplift; notably, two mantle uplifts are observed beneath the Xialiaohe Basin, consistent with gravity data and seismic reflection profiles. The Liaodong Uplift generally exhibits a Poisson ' s ratio lower than 0.26 and no significant residual topographic anomalies. In contrast, the Lower Liaohe Basin features an average Poisson ' s ratio exceeding 0.3, with distinct positive residual topography anomalies reaching a maximum amplitude of 1.18 km, which suggest that, due to the tensile stress, there may be local melting or upwelling of mantle-derived material, resulting in crustal thinning. The regional tectonic stress and the upwelling of the mantle material may jointly affect the seismic activities at the eastern edge of the Xialiaohe Basin and inside the Liaodong Uplift.