Chuang Xu¹, Haihong Wang^{*2, 3}, Zhicai Luo¹, Hualiang Liu⁴, Xiangdong Liu¹
1. MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
2. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China
3. Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University, Wuhan 430079, China
4. China Water Resources Beifang Investigation, Design and Research Co. Ltd., Tianjin 300222, China
Chuang Xu: http://orcid.org/0000-0002-8223-3021; Haihong Wang: http://orcid.org/0000-0002-0106-8360

ABSTRACT: Urban faults in Shenzhen are potential threat to city security and sustainable development. To improve the knowledge of the Shenzhen fault zone, interpretation and inversion of gravity data were carried out. Bouguer gravity covering the whole Shenzhen City was calculated with a 1-km resolution. Wavelet multi-scale analysis (MSA) was applied to the Bouguer gravity data to obtain the multilayer residual anomalies corresponding to different depths. In addition, 2D gravity models were constructed along three profiles. The Bouguer gravity anomaly shows an NE-striking high-low-high pattern from northwest to southeast, strongly related to the main faults. According to the results of MSA, the correlation between gravity anomaly and faults is particularly significant from 4 to 12 km depth. The residual gravity with small amplitude in each layer indicates weak tectonic activity in the crust. In the upper layers, positive anomalies along most of faults reveal the upwelling of high-density materials during the past tectonic movements. The multilayer residual anomalies also yield important information about the faults, such as the vertical extension and the dip direction. The maximum depth of the faults is about 20 km. In general, NE-striking faults extend deeper than NW-striking faults and have a larger dip angle.

https://doi.org/10.1007/s12583-017-0770-4