The earthquake occurred as a result of shallow (10 km depth) strike-slip faulting at the northeastern Tibetan Plateau. It ruptured a fault located near the Qilian Mountains. The geological structure responsible was the Lenglongling Fault, a segment of the
Haiyuan Fault System. The rupture was mostly confined to 0–8 km within the upper crust. A maximum slip of 3.5 m was estimated at 4 km depth.[7]Surface ruptures were observed for a length of 22 km, and the maximum surface displacement was 2.1 m. The evaluated maximum Modified Mercalli intensity was IX (Violent) near the rupture zone. Intensity VI (Strong) was felt over an area of at least 23,417 km2.[1]
By January 17, 2022, at least 584 aftershocks were recorded, and the largest measured Mw 5.3. The aftershocks were distributed along a 40 km-long zone trending east-west. Many were detected at depths of 7–14 km, beneath the main rupture area. Only a few aftershocks were detected within 5 km of the crust.[7]
Damage and injuries
The earthquake damaged at least 137 homes and collapsed two walls in
Zhangye.[8] Four people in
Menyuan Hui Autonomous County suffered minor injuries while evacuating.[3] In total, nine people were reported to be injured, eight of them were discharged from hospitals by the following day.[9]
Some bridges and tunnels on the
Lanzhou–Xinjiang high-speed railway sustained serious damage and traffic was halted until repairs could be completed.[10]
The
Great Wall of China was also damaged by the quake. A 2 m (6 ft 7 in) section of the wall in
Shandan County, built during the
Ming Dynasty, collapsed. As of January 2022, repair and restoration work on this section was underway.[11]
^"青海门源6.9级地震烈度图发布 最高烈度为IX度(9度)" [Qinghai Menyuan M6.9 earthquake intensity map released, the highest intensity is IX degree (9 degree)].
Archived from the original on 12 January 2022. Retrieved 3 June 2022.