Thickness and vP/vS of sedimentary and bedrock layers in the crust in the Yuan’an Graben and their tectonic implication

• Published in: 地震科学进展 Vol. 55; no. 8; pp. 446 - 455
• Main Authors: Qi Deng, Zigen Wei
• Format: Journal Article
• Language: Chinese
• Published: Editorial Office of Progress in Earthquake Sciences 01.08.2025
• Subjects: multi-layer h-κ stacking of receiver function; shale gas; thickness and vp/vs of sedimentary and bedrock layers; yuan’an graben
• ISSN: 2096-7780
• DOI: 10.19987/j.dzkxjz.2024-086

The Yuan’an Graben, which holds abundant shale gas, is located at the junction of the Jianghan Basin and the Huangling Block. Information about the graben’s deep structure has great significance for analysis of the basin-mountain interaction and the sedimentary response of shale gas. In this study, the thickness and vP/vS of the sedimentary and bedrock layers beneath seven temporary seismic stations in the Yuan’an Graben were obtained using the multi-layer H-κ stacking approach of receiver function. The results show that the average thickness and vP/vS of the sedimentary layer in the Yuan’an Graben are 3.68 km and 1.98, respectively. Those of the bedrock layer are 31.51 km and 1.70, respectively. The average crustal thickness is 35.19 km, and the average vP/vS is 1.73. These observations support the inference that the Yuan’an Graben has experienced thinning of the lower crust under long-term basin-mountain interaction, but the crust as a whole still maintains the characteristics of typical cratonic crust. The