Aftershocks expected after M7.1 earthquake hits NW China's Xinjiang

Aftershocks are likely after a magnitude-7.1 earthquake hit Wushi County in Aksu Prefecture in northwest China's Xinjiang Uygur Autonomous Region, according to an expert at the China Earthquake Networks Center (CENC).

Based on comprehensive analysis of regional tectonic characteristics, historical seismic activity levels, sequence characteristics and geophysical observations, the magnitude-7.1 earthquake is likely to be a mainshock-aftershock sequence-type, meaning that a series of smaller aftershocks will follow around the epicenter after the first large earthquake occurs, said Han Yanyan, a senior engineer at the CENC.

As of 8 a.m. on Tuesday, 40 earthquakes of magnitude 3 or above had been recorded, and the largest aftershock was measured at magnitude 5.3, according to the CENC. Han added that it's possible that strong aftershocks will take place in the following days.

The Tianshan seismic zone is located in Central Asia, with the Pamir Plateau and Tarim Basin in the south and the Kazakh Platform and Junggar Basin in the north. Since the Cenozoic Era, the area has had strong tectonic movements due to the long-range effects of the strong collision and continuous compression of the Indian Plate against the Eurasian Plate. In this area, an earthquake of magnitude-7 or above occurs once about every seven years on average, and a magnitude-7.2 earthquake hit Tajikistan on February 23, 2023, noted Han. 

Due to its large magnitude and focal depth of 22 kilometers, Tuesday's earthquake is classified as a shallow earthquake. Therefore, the quakes were felt relatively strongly in various cities and prefectures across Xinjiang, including Aksu, Artux, Kashgar, Ili, Korla and Karamay. The population within 20 kilometers of the epicenter is extremely sparse.

(Cover image via CFP)