
A video the police posted, opens new tab on TikTok sister app Douyin showed officers packing supplies in a truck in the dark and inspecting a building and rubble with flashlights.
More than 12,000 people have been safely relocated, state media outlet Xinhua reported.
Videos previously released by local official media showed people leaving their homes and seeking shelter outside or in their cars parked on the street. One resident reported being awakened by the strong quake and hearing the house squeaking during the tremor.
The China Earthquake Networks Center said in a post that 413 aftershocks had been recorded.
In 2010, a magnitude 7.1 tremor struck Yushu in neighbouring Qinghai province, killing at least 2,698 people and leaving nearly 300 people missing.