Zigong, Sichuan is located on Huaying Mountain fault zone. The surface of the fault zone extends from Dazhou to the south, passing through Guang 'an, Hechuan, Rongchang, Zigong and Yibin, and its activity is not strong, with only moderate earthquakes of magnitude 4~5. Zigong has long been a moderately seismically active area. From 1896 to 1985, there were three moderate earthquakes with magnitude above 4, and Yibin and Rongchang also had earthquakes with magnitude above 5.
Generally speaking, Wenchuan is located in the North-South seismic belt, a major seismic belt in China. Experts from the Seismological Bureau of China believe that due to the great differences in geological distribution, crustal thickness and crustal movement speed between the east and the west of China, the earthquake occurred in the zone with the greatest difference between the east and the west, that is, the North-South seismic zone, which includes from Ningxia to Yunnan via eastern Gansu and western Sichuan, which is an earthquake-intensive zone.
The macro explanation is that "the Indian Ocean plate collided with the Eurasian plate from south to north, and the collision zone arched the Qinghai-Tibet Plateau." Professor Ni Sidao from the School of Earth and Space Sciences of China University of Science and Technology said, "The Qinghai-Tibet Plateau is uplifting, but it is also moving to the northeast, squeezing the Sichuan Basin to slide to the northeast. The Wenchuan earthquake occurred in the southeast of the Qinghai-Tibet Plateau."