Research the shallow structure of the Northern China Basin using near earthquake Sp converted waves and teleseismic P wave delay

We collected the local shock seismic waveforms and teleseismic waveforms with high signal-to-noise ratio which recorded by broadband seismic observatories deployed in Northern China from 2017 to 2020. The thickness of the sedimentary layer in Northern China is estimated to be 6 similar to 7 km by using teleseismic receiver function P-wave peak delay and local shock Sp converted wave time delay. The thickness of the sedimentary layer in the Yanshan orogenic belt is relatively thin, with a burial depth of crystal basement generally less than 1 km. The burial depth of crystal basement in the central and southeastern basins of Northern China Basin is relatively large, with a thickness generally greater than 3 km, and local thickness up to 7 km. The Xingheng uplift in the basin has 3 km thickness sedimentary layer, while the Jizhong and Huanghua depressions have a thickness of 6 similar to 7 km; The thickness of the sedimentary layer corresponds to the tectonics. The thickness of the sedimentary layer in the depression area is larger, and the thickness of the sedimentary layer in the uplift area is thin, which reflects the settlement difference of different secondary blocks in the sedimentary basin. The seismic phase picking error, source azimuth and Epicentral distance have no obvious influence on the sediment thickness calculation results, while the accuracy of the one-dimensional velocity model used for time depth conversion has a certain impact on the calculation results. In general, teleseismic receiver function P -wave peak delay and local shock Sp converted wave time delay can be used to study the thickness of sedimentary layers, and it can determine the characteristics of the thickness structure of sedimentary layers reliably and effectively, providing basic information for seismic risk assessment.