Traditional Culture Encyclopedia - Travel guide - Cities in the Gansu earthquake zone

Cities in the Gansu earthquake zone

The scope of Gansu Province roughly includes Yumenguan to the south of Shule River, north of Yumen and Subei Danghe River, east to Huahai Basin, and west to Xinjiang and Qinghai, all in the seismic zone.

Gansu Province is located in the northeastern part of the strongly uplifted Qinghai-Tibet Plateau and its crustal thickness variation zone, straddling the transition zone between the eastern platform and the western geosyncline area of ??mainland China. The topography and geological structure within the territory are extremely complex, and the new Tectonic activity is intense.

Several major tectonic systems in China, such as the Qilüheshan-shaped structure, the Neocathaysian structure, the Hexi structure, etc., are all spread, turned, and intersected in Gansu Province. The large-scale Altyn Tagh active fault, Changma active fault, and active fault on the northern edge of Longshou Mountain from west to east are almost distributed throughout Gansu Province, and they also control the uneven distribution of active zones in Gansu Province's strong earthquake provinces.

The Hexi Corridor seismic zone includes the Qilian Mountains seismic zone and the Minqin seismic zone, which runs northwest to northwest. The east end borders the west wing of the north-south seismic zone, the Altyn seismic zone to the west, Jinta and Alxa in North Vietnam. Entering Inner Mongolia, the southern boundary enters Qinghai. Earthquakes occurring in this zone are mostly controlled by the strong activity of deep northwest-trending faults.

Introduction to the North and South Seismic Zones:

This is a famous seismic zone in mainland China. The distribution scope of Gansu Province starts from Minqin in the north, bordering Ningxia and Inner Mongolia, and ends in Wenxian County in the south, connected to Sichuan, Shaanxi, and Qinghai, basically including the central and eastern regions of Gansu. It is surrounded by the Yinchuan seismic zone to the north, the Hexi Corridor seismic zone and the Qilian Mountains seismic zone to the west, the Weihe Plain seismic zone to the east, and the middle section of the North-South seismic zone entering Sichuan to the south.

The seismic activity in this zone is characterized by high frequency, high intensity and short period. Since historical records began in 193 BC, there have been 65 destructive earthquakes of moderate strength or above in the belt, including 12 earthquakes of magnitude 7 or above. The only four major earthquakes of magnitude 8 or above in the history of Gansu Province all occurred in Gansu Province. This area.

The geological structures in the belt are extremely complex and criss-crossed. There are large strike-slip fault zones running NWW and NEE. The deep north-south structures are significant, which control the occurrence of strong earthquakes in the zone. Analysis of historical data shows that earthquakes in the zone have the characteristics of migrating from south to north and from west to east. Today's weak earthquake activity has obvious characteristics of banding, enclosure and intersection.

Since the area where this belt is spread is an area with relatively developed industry, economy, and culture in Gansu Province and a high population density, it is not only an important seismically active zone in Gansu Province, but also one of the areas most affected by earthquake disasters. heavy areas.