Regional differences in crustal structure beneath northeastern China and northern North China Craton: constraints from crustal thickness and Vp/Vs ratio

Using teleseismic waveform records collected from 127 permanent seismic stations which are distributed relatively evenly, in combination with previous studies from 97 temporary seismic stations, we obtained the crustal thickness (H) and average crustal V-p/V-s, ratio (kappa) beneath the northeastern China and northern North China Craton (NCC) by H-kappa stacking of receiver functions. The results show relatively thin H and complicated variations both in kappa and crustal density, which suggest intense and uneven reactivation and modification of crust during the Mesozoic-Cenozoic times. Significant E-W difference in crust was imaged in the northeastern China and northern NCC. In northeastern China, H thickens nearly linearly as the elevation increases in the Xingmeng orogenic belt located in the west. H changes from 31 km to 39 km with an average of similar to 35 km, kappa varies from 1.71 to 1.83 with an average of similar to 1.77. No clear correlation was observed between H and elevation in the Jihei fold belt located in the east. The values of H are in a range from 28 km to 37 km with an average of similar to 33 km. kappa varies from 1.72 to 1.89 with an average of similar to 1.79. In the northern NCC, H thickens from east to west in the Yanshan belt located in the west, and changes from 28 km to 40 km with an average of similar to 34 km. kappa is concentrated in a range from 1.70 to 1.91 with an average of similar to 1.79. H is larger in the middle in the Liaodong anteclise located in the east, and ranges from 29 km to 35 km with an average of similar to 32 km. kappa changes from 1.71 to 1.83 with an average of similar to 1.77. Complicated variations and a large range in kappa and relatively smaller H were observed in the Jihei fold belt (the northeastern China). This suggests that this region may have experienced more intense crustal modification and thinning related to the Pacific plate subduction because of the inherent complexity in crustal structure and being adjacent to the Pacific plate. In the northern NCC, complicated variations and large ranges both in H and kappa in the Yanshan belt indicate that this region probably underwent a more complex crustal modification which may Central Asia Orogenic Belt accretion and Pacific plate subduction.