Along‐Strike Variation of Convergence Rate and Pre‐Existing Weakness Contribute to Indian Slab Tearing Beneath Tibetan Plateau
Qihua Cui, Zhong‐Hai Li
Abstract
Abstract A number of geophysical observations reveal that the underthrusting Indian continental plate beneath the southern Tibetan Plateau is laterally torn and segmented, with contrasting subduction angles along strike. However, the mechanism of such kind of slab tearing remains unclear. Here, a series of 3‐D high‐resolution numerical models are conducted, which suggest that the lateral variation (either gradually or abruptly changing) of boundary convergence rate plays a critical role in the tearing of underthrusting continental slab. The abruptly changing convergence with a large lateral contrast could lead to slab tearing all by itself, whereas the gradually changing convergence should be combined with pre‐existing weakness in the underthrusting block. The structures and properties of overriding block play secondary roles. Finally, we propose that Indian slab tearing could be attributed to the time‐dependent and lateral variation of convergence rate during the Indian‐Asian collision and the pre‐existing Indian lithospheric weakness.