Block Kinematics in North China From GPS Measurements

Abstract

North China, commonly known as the North China Craton (NCC), is an important tectonic element in eastern China (R. Zhu et al., 2011Zhu et al., , 2012. This region is characterized by complex tectonic setting, intense seismic activity and dense population (Deng et al., 2003). Unlike the Tibetan Plateau situated in western China, where numerous active faults exhibit fast motions and significant deformation, the faults in the NCC generally have slow motions (Deng et al., 2002). However, numerous strong earthquakes have occurred in this region during the past hundred years, including the 1976 M 7.8 Tangshan event that has caused huge casualties (P. Zhang et al., 2013). In this context, quantifying the faulting kinematics and slip partitioning holds great significance for seismic risk assessments.Over the past decades, numerous studies have been conducted on the tectonic processes and deformation mechanisms in the NCC. For example, it has been suggested that most deformation features in the NCC can be explained as the combined effects of the India-Eurasia collision and Pacific subduction (Ye et al., 1987;Yin, 2010); however, the relative significance involving with these two factors remains unclear. Moreover, several studies have proposed that the late Cenozoic tectonics in this region is mainly characterized by widespread rifts that have caused intensive extensional deformation (Y. Q. Zhang et al., 1998

Present‐Day Strike‐Slip Faulting and Intracontinental Deformation of North China: Constraints From Improved GPS Observations

“…The resulting block model predicts right‐lateral slip along the NNE‐ and NE‐trending boundary faults between the Ordos, Taihangshan, and Haihe Plain blocks (Figure 7d), which agrees with the geological observations (e.g., Jing et al., 2016; X. Xu & Ma, 1992; X. W. Xu et al., 1993; Y. R. Xu et al., 2018; Yu et al., 2021), geodetic measurements (e.g., Hao et al., 2021; W. Wang et al., 2022; Y. G. Zhang et al., 2018; B. Zhao et al., 2017), and focal mechanisms (e.g., B. Li et al., 2015; P. E. Li et al., 2018; Y. C. Li et al., 2015; Seismological Bureau of Hebei Province, 1986). Owing to the inclusion of secondary active faults in contrast to oversimplifying them into a single straight line in the previous studies (Hao et al., 2021; Huang et al., 2018; W. Wang et al., 2022; Y. G. Zhang et al., 2018), it allows us to better predict the fault kinematics and investigate the details of strain partitioning in this area. Our results show that active faults at the eastern margin of the Weihe Graben slip right‐laterally, opposite to the left‐lateral faults at its northwestern margin (Figure 7d).…”

“…Xu & Ma, 1992; X. W. Xu et al, 1993;Y. R. Xu et al, 2018;Yu et al, 2021), geodetic measurements (e.g., Hao et al, 2021;W. Wang et al, 2022;Y.…”

“…A key structure in continental China is the ∼3,500 km long left‐lateral strike‐slip Altyn Tagh‐Haiyuan‐Qinling fault system (AHQFS), which is proposed to be the primary boundary fault system that accommodates the eastward extrusion of the Tibetan Plateau and South China Block with respect to North China in the lateral extrusion hypothesis (Jiao et al., 2023; Peltzer et al., 1985; Tapponnier et al., 1982, 2001; Y. Q. Zhang et al., 1995, 2003). To test the eastward extrusion model and to explain the mechanisms of extensional tectonics in North China, an extensive geodetic effort has been dedicated to determine the slip rates of the Altyn Tagh Fault (e.g., Bendick et al., 2000; Gan et al., 2007; He et al., 2013; Y. C. Li et al., 2018, 2022; Loveless & Meade, 2011; Shen et al., 2001; G. Zheng et al., 2017), Haiyuan Fault (e.g., B. Li et al., 2015; X. N. Li et al., 2021; Y. C. Li et al., 2015; Y. H. Li et al., 2018; Thatcher, 2007; H. Wang et al., 2011; W. Wang et al., 2017; G. Zheng et al., 2017; W. J. Zheng et al., 2013), and Qinling Fault (e.g., Hao et al., 2016; Huang et al., 2018; Jin et al., 2007; Middleton, 2016; Qu et al., 2014; H. Wang et al., 2011; W. Wang et al., 2022). However, the details of how left‐lateral slip rate decreases eastward and terminates at the eastern termination of the AHQFS are still poorly constrained.…”

“…Although a lot of work has been done in North China, the details of strain partitioning in this area remain unclear. This is primarily due to the fact that previous studies have oversimplified the complex boundaries between the Ordos, South China, and Taihangshan blocks by representing them as a single straight line (Hao et al., 2021; Huang et al., 2018; H. Wang et al., 2011; W. Wang et al., 2022; Y. G. Zhang et al., 2018), resulting in the omission of critical information. Besides, moderate‐to‐large earthquakes have occurred within the North China Plain block (Gu et al., 1983; National Earthquake Data Center, http://data.earthquake.cn/index.html; Figure 1), reflecting that deformation is also distributed within an area that had previously been recognized as a rigid block.…”

“…Zheng et al, 2013), and Qinling Fault (e.g., Hao et al, 2016;Huang et al, 2018;Jin et al, 2007;Middleton, 2016;Qu et al, 2014;H. Wang et al, 2011;W. Wang et al, 2022).…”