He Huang1,2, Xuzhang Shen1,2*, Jian Xu1,2, Rui Gao1,2, Wentian Wang1,2, Qiming Zhou1,2, and Qiangqiang Huang1,2
1 Guangdong Provincial Key Laboratory of Geodynamics and Geohazards, School of Earth Sciences and Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
2 Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China.
Corresponding author: Xuzhang Shen (shenxzh5@sysu.edu.cn)
Key Points:
Abstract
To better constrain the amalgamation of the East and West Cathaysia blocks, we deployed a short-period dense seismic array oriented nearly north-south in the southwestern Cathaysia block. According to the 997 teleseismic receiver functions recorded by 527 node geophones, we find that the Mohorovicic discontinuity (Moho) is slightly uplifted towards the coastal Cathaysia block. The most obvious feature is the high Vp/Vs ratio and deepen Moho beneath the Sanshui basin. Based on the common conversion point (CCP) migration images, we deduce that there may be distributed with the extension of the Gaoyao-Huilai deep fault, and it is supported by the offset of Moho and occurrence of the Mw 4.3 earthquake. Combined with other evidences, we further concluded that a weak suture zone is constrained beneath along the Zhenghe–Dapu and Gaoyao–Huilai deep faults, which may indicate the remnants of the amalgamation of the East and West Cathaysia blocks.