Preliminary study of lateral variation in crustal structure of Northeast China from teleseismic receiver functions

We conducted comprehensive receiver function analyses for a large amount of high-quality broadband teleseismic waveforms data recorded at 19 China National Digital Seismic Network (CNDSN) stations deployed in Northeast China. An advanced <i<H</i<-<i<κ</i< domain search method was adopted to accurately estimate the crustal thickness and <i<v</i<<sub<P</sub</<i<v</i<<sub<S</sub< ratio. The crust has an average thickness of about 34.4 km. The thinnest crust occurs in the central region of Northeast China, while the thickest crust is beneath the Yanshan belt. The <i<v</i<<sub<P</sub</<i<v</i<<sub<S</sub< ratio is relatively uniform with an average of about 1.733. The highest <i<v</i<<sub<P</sub</<i<v</i<<sub<S</sub< ratio is found beneath the Changbaishan, likely associated with its volcanic activities. We found significant lateral heterogeneity beneath three stations CN2, MDJ, and MIH located along the Suolon suture from the back-zimuthal dependence of Moho depth. The velocity modeling from receiver functions indicated complicated Earth structure beneath these stations with large crust-mantle transition zone, noticeable velocity jump in upper mantle, and low velocity zone in middle crust. Dipping velocity interface in the crust with strike approximately parallel to the Suolon suture and down-dip to the south or southeast might explain the observed lateral heterogeneity.