Large Surface-Rupture Gaps and Low Surface Fault Slip of the 2021 Mw 7.4 Maduo Earthquake Along a Low-Activity Strike-Slip Fault, Tibetan Plateau

Based on field investigations, interpretations of high-resolution UAV images, and analyses of available InSAR data, we mapped the fault geometry and surface ruptures of the 2021 M-w 7.4 Maduo earthquake that occurred on a low-activity strike-slip fault within the Tibetan Plateau. The results indicate that (a) the earthquake activated a fault that is similar to 161 km long and has complicated structural geometry; (b) the surface rupture occurs over a distance of 148 km, but is separated into three distinct segments by two large gaps (38 and 20 km, respectively); (c) within the surface-rupture segments, the horizontal and vertical displacements are typically 0.2-2.6 m (much lower than the InSAR-based slip maximum of 2-6 m at depth) and <= 0.4 m, respectively. The two large gaps of the Maduo surface rupture represent the two largest surface-rupture discontinuities of strike-slip earthquakes ever documented, and coincide with structurally complicated fault portions and near-surface soft sediments.

Automated summary

Based on field investigations, high-resolution UAV images, and InSAR data analysis, this study mapped the fault geometry and surface ruptures of the 2021 M-w 7.4 Maduo earthquake. The results showed that the earthquake activated a fault with complicated structural geometry, and the surface rupture spanned 148 km, divided into three distinct segments by two large gaps.