Formation of the V-shaped conjugate strike-slip faults revealed by crustal anisotropy in the central Tibetan Plateau

• Published in: Journal of Asian earth sciences 2023-12, Vol.258, p.105725, Article 105725
• Main Authors: Nie, Shitan, Li, Jiangtao, Wu, Chenglong, Tan, Ping
• Format: Article
• Language: English
• Subjects: Conjugate strike-slip faults; Crustal decoupling; Plastic deformation; Seismic anisotropy; The central Tibetan Plateau
• ISSN: 1367-9120; 1878-5786
• DOI: 10.1016/j.jseaes.2023.105725

[Display omitted] •Crustal anisotropy results suggest simple shear deformation may be the main mode of crustal deformation in the central Tibetan Plateau.•A weak crustal anisotropic belt is observed beneath the Bangong-Nujiang Suture (BNS).•The weak deformation beneath the BNS and strong deformation on both sides lead to the formation of conjugate strike-slip faults. The dynamic processes responsible for the formation of the conjugate strike-slip faults in the central Tibet remain poorly understood. The crustal anisotropy can provide important constraints on the crustal deformation history and current state. Using data from a recently deployed seismic array (SANDWICH), we obtained crustal anisotropy results that reveal the deformation of the crust in the central Tibet with high resolution. The results show that most stations exhibit strong crustal anisotropy and nearly E-W fast orientations. Our results, when combined with previously revealed upper crustal anisotropy, indicates that the deformation in the upper and mid-lower crust is decoupled. The most prominent feature in our results is a weak crustal anisotropy belt along the BNS, suggesting the mid-lower crust has not undergone strong deformation. We propose that the combination of stable BNS and strong deformation on both sides of BNS in the mid-lower crust caused the formation of conjugate strike-slip faults.