# InSAR analysis reveals insights into the Ms 6.2 earthquake rupture and tectonic dynamics of the northeast margin of the Qinghai‒Tibet plateau

## TL;DR

A 2023 earthquake in China's Gansu Province was studied to understand its fault mechanisms and tectonic dynamics, revealing how strain is released in the Qinghai-Tibet Plateau region.

## Contribution

The study identifies a unique mode of strain release through local block rotation at the northeastern margin of the Qinghai-Tibet Plateau.

## Key findings

- The earthquake was a shallow thrust event with a maximum slip of 0.7 meters and a minor dextral strike-slip component.
- A small-scale dextral adjustment fault at the intersection of Lajishan, the Yellow River, and Jishishan likely caused the dextral component.
- Strain release through local block rotation contributes to the unique expansion mode of the Qinghai-Tibet Plateau's northeastern margin.

## Abstract

On 18 December 2023, an Ms 6.2 earthquake occurred in Jishishan County, Linxia Prefecture, Gansu Province, China. As the strongest seismic event in the region since records began, it caused significant casualties and property damage while providing a valuable opportunity to investigate local seismogenic structures. In this study, the seismogenic structure and seismogenesis mechanism of earthquakes were explored through high-precision coseismic deformation analysis and fault modeling combined with regional tectonic background and aftershock distribution data. The results indicate that the earthquake was a typical shallow thrust event with a maximum slip of 0.7 m and a minor dextral strike-slip component. A small-scale dextral adjustment fault that developed at the intersection of Lajishan, the Yellow River, and Jishishan is presumably the primary controlling factor for the dextral component. This study revealed that the northeastern margin of the Qinghai‒Tibet Plateau achieves strain release through local block rotation, resulting in a unique plateau expansion mode. These findings are crucial for understanding the tectonic evolution at the frontal edge of the Himalayan collision zone and improving regional strong earthquake risk assessment.