Mapping Lateral Variations of Crustal Structure across China with Pds Receiver Function Data

Abstract:

We analyzed a large amount of high-quality broadband teleseismic waveforms recorded at 900+ permanent stations of the national and regional seismic networks of the China Earthquake Administration (CEArray) to estimate the lateral variations of crustal structure across China using receiver function techniques. The measured crustal thickness varies from 29 to 37 km in the eastern part of China, and gradually increase to ~45-50 km towards the central and northwestern parts. The crust beneath the entire Tibetan plateau is as thick as 60 km and extends to over 80 km in several locations. The estimated crustal thickness generally shows a positively correlation with surface topography in most of the study area, but does break in some regions, such as the Tianshan mountain range, the Songliao basin and the Changbaishan-Zhangguangcai Range. The linear slope derived from the crustal thickness and surface topography data shows significant lateral variations, indicating that there exist large variations in density structure across the study area. We also use amplitude ratio between the Ps conversion and reverberation phases to constrain density contrast across the Moho. Our preliminary results indicate that two methods produce roughly similar lateral variations in density structure.