Present-Day Deformation of the Gyaring Co Fault Zone, Central Qinghai–Tibet Plateau, Determined Using Synthetic Aperture Radar Interferometry

Abstract

Because of the constant northward movement of the Indian plate and blockage of the Eurasian continent, the Qinghai–Tibet Plateau has been extruded by north–south compressive stresses since its formation. This has caused the plateau to escape eastward to form a large-scale east–west strike-slip fault and a north–south extensional tectonic system. The Karakorum–Jiali fault, a boundary fault between the Qiangtang and Lhasa terranes, plays an important role in the regional tectonic evolution of the Qinghai–Tibet Plateau. The Gyaring Co fault, in the middle of the Karakoram–Jiali fault zone, is a prominent tectonic component. There have been cases of strong earthquakes of magnitude 7 or greater in this fault, providing a strong earthquake occurrence background. However, current seismic activity is weak. Regional geodetic observation stations are sparsely distributed; thus, the slip rate of the Gyaring Co fault remains unknown. Based on interferometric synthetic aperture radar (InSAR) technology, we acquired current high-spatial resolution crustal deformation characteristics of the Gyaring Co fault zone. The InSAR-derived deformation features were highly consistent with Global Positioning System observational results, and the accuracy of the InSAR deformation fields was within 2 mm/y. According to InSAR results, the Gyaring Co fault controlled the regional crustal deformation pattern, and the difference in far-field deformation on both sides of the fault was 3–5 mm/y (parallel to the fault). The inversion results of the back-slip dislocation model indicated that the slip rate of the Gyaring Co fault was 3–6 mm/y, and the locking depth was ~20 km. A number of v-shaped conjugate strike-slip faults, formed along the Bangong–Nujiang suture zone in the central and southern parts of the -Tibet Plateau, played an important role in regional tectonic evolution. V-shaped conjugate shear fault systems include the Gyaring Co and Doma–Nima faults, and the future seismic risk cannot be ignored.

Joint InSAR and Field Constraints on Faulting During the Mw 6.4, July 23, 2020, Nima/Rongma Earthquake in Central Tibet

“…Toward the southeast, south of the BNS, the late Quaternary slip rate along the dextral Gyaring Co fault (GCF) has been estimated to be between 2 and 4.5 mm/yr, based on lacustrine shoreline and alluvial fan offsets (Shi et al, 2014;D. Wang et al, 2016), while present-day geodetic rates derived from GPS and InSAR data range between 2 and 6 mm/yr (H. Wang et al, 2011Wang et al, , 2019Y. Zhang et al, 2019).…”

“…About 170 km eastwards, the throw rate along the master normal fault of the Shuanghu graben has been estimated to be less than 0.1 mm/yr (Blisniuk & Sharp, 2003). Toward the southeast, south of the BNS, the late Quaternary slip rate along the dextral Gyaring Co fault (GCF) has been estimated to be between 2 and 4.5 mm/yr, based on lacustrine shoreline and alluvial fan offsets (Shi et al., 2014; D. Wang et al., 2016), while present‐day geodetic rates derived from GPS and InSAR data range between 2 and 6 mm/yr (H. Wang et al., 2011, 2019; Y. Zhang et al., 2019). One should note here, however, that faster rates (up to between ≈1 and 1.5 cm/yr) have been previously inferred along the GCF from both InSAR and Quaternary studies (e.g., Armijo et al., 1989; Chung et al., 2008; Taylor & Peltzer, 2006).…”

Incorporating Persistent Scatterer Interferometry and Radon Anomaly to Understand the Anar Fault Mechanism and Observing New Evidence of Intensified Activity

“…Various methods have been used to investigate the activity of faults, including geomorphological evidence, morphostructural analyses, and paleoseismology [11][12][13][14][15][16][17][18]. Today, with remote sensing science development, especially in radar imaging, a new door has been opened to study the displacement of the Earth's crust [19,20]. The radar interferometry methods are increasingly used to study faults, earthquakes, subsidence, and other natural hazards [21][22][23][24][25][26][27].…”