Present–day crustal deformation across the Daliang Shan, southeastern Tibetan Plateau constrained by a dense GPS network

Abstract

Summary The Daliang Shan is a tectonic unit that connects the active southeastern Tibetan Plateau with the stable South China block. As a newly generated (formed later than the Xianshuihe–Xiaojiang active fault system) seismotectonic zone induced by the Tibetan tectonics, the detailed constraints of the crustal deformation are central to the understanding of the kinematics and dynamics of the Tibetan expansion. This paper establishes and analyzes a high–spatial resolution global positioning system (GPS) velocity field from a dense GPS network in this region. Our modeling results indicate that, in contrast to the equivalent sinistral strike–slip rate of approximately 5 mm/yr on the Anninghe–Zemuhe and Daliangshan faults, their inferred interseismic locking depth varies within a large range. The southern segment of the Anninghe Fault and the middle segment of the Daliangshan Fault have deep locking depths of ∼13 km, indicating that the seismic risk is high in these areas. In addition, the detectable counterclockwise rotation rate of 0.35 ± 0.12°/Myr of the Mabian block makes a significant contribution of ∼50 per cent to the strike–slip motion on its boundary faults. This counterclockwise rotation may be induced by a left-lateral shear gradient with SE-ward motion relative to the South China-fixed reference frame, indicating the significance of a simple-shear pattern in exploring the kinematics of the encroachment of the Tibetan tectonics upon a stable block (craton).

An Updated Fault Coupling Model Along Major Block‐Bounding Faults on the Eastern and Northeastern Tibetan Plateau From a Stress‐Constrained Inversion of GPS and InSAR Data

“…The block geometry is from Styron (2022a), shown in Figure 1, which is constructed based on the detailed geological fault traces with reference to previous geodetic studies. Compared to previous block geometry of the Tibetan plateau (e.g., Loveless & Meade, 2011a; Meade, 2007; Y. H. Li et al., 2023; Shen et al., 2005; Thatcher, 2007; Xu & Stamps, 2016), this block geometry is broadly consistent with high‐resolution fault mapping in greater detail over a broad area on the plateau and surrounding vast region, also called fault‐based block model. In this study, the block model contains 65 blocks, which sufficiently cover the northeastern and eastern Tibetan plateau.…”

“…For GPS measurements in the surrounding region of the western Kunlun and Longmenshan faults, co‐ and time‐dependent postseismic deformation associated with the 2001 Mw 7.8 Kokoxili, 2008 Mw 7.9 Wenchuan and 2013 Mw 6.6 Lushan earthquakes have been estimated and removed (refer to Wang and Shen (2020); Y. H. Li et al. (2023) for full details). All GPS data sets are originally expressed in different reference frames and then combined into a common reference frame, using the results of Wang and Shen (2020) as the reference, by reducing the best‐fitting rotation pole between overlapping stations in each data set (Kreemer & Gordon, 2014).…”

“…Geodetic observations of surface velocities from InSAR and GPS are suitable for direct quantification of the distribution and degree of kinematic coupling on fault segments over the period of geodetic measurements (e.g., Bürgmann et al., 2005; McCaffrey et al., 2002; Pollitz et al., 2008). Previous studies have investigated the locking depth or coupling distribution along specific or several faults constrained by GPS and/or InSAR measurements in Tibet (e.g., Chen et al., 2004; He & Chéry, 2008; Huang & Zhou, 2022; Jian et al., 2020; Jiang et al., 2015; Loveless & Meade, 2011a; Y. C. Li et al., 2023; Y. H. Li et al., 2023; Li & Bürgmann, 2021; Ou et al., 2022; Shen et al., 2005; Thatcher, 2007; Zhao et al., 2020, 2022a; Zhu et al., 2021). The previous studies collectively demonstrated the heterogeneous pattern of fault coupling distribution on multiple fault segments, in which isolated locked regions of varied sizes are surrounded or bordered by creeping/partially locked zones.…”

Kinematic Slip Evolution During the 2022 Ms 6.8 Luding, China, Earthquake: Compatible With the Preseismic Locked Patch

“…The fault‐perpendicular profile across the Moxi fault confirms that there indeed is a long‐wavelength associated with the relative interseismic motion, indicating that the Moxi fault has been undergoing energy accumulation. It is also corroborated by multiple interseismic locking models (Figure 4, L. Li et al., 2022; Qiao & Zhou, 2021; X. Li et al., 2021; Yuhang Li et al., 2022). The occurrence of thea 1786 Ms 7.75 earthquake also verified the potential of the Moxi fault to harbor larger magnitudes (Dai et al., 2005).…”

Geochemical Characteristics of Thermal Springs and Insights Into the Intersection Between the Xiaojiang Fault and the Red River Fault, Southeastern Tibet Plateau

“…For the southern section, some researchers have calculated a slip rate of 7-9 mm/a (Q. Z. Li et al, 2019;Z.…”