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:
- A short-period dense seismic array in the southwest Cathaysia block
- The slight uplift of Moho towards the coastal area
- Abnormal deepen Moho and high Vp/Vs ratio beneath the Sanshui basin
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.