关键词: 汶川大地震, 中亚三角形地震带, 力学脆弱带, 构造应力场, 滑移线场, 介质力学条件, 壳内低阻流变层

Abstract:

 There is a giant triangle seismic zone in Central Asia, which is composed of the China NorthSouth Seismic BeltMongolia Eastern Seismic Zone, the PamirTianshanAltayMongolia Western Seismic Belt and the Himalayan Seismic Belt, forming the three sides of the triangle. The highintensity, high frequentness, high repetition rate, and short repeat cycle of large earthquakes in the triangle seismic zone are unique in the continents of the world. These large earthquakes were controlled complexly by tectonic location, tectonic stress field, slipline field, media mechanics conditions, low resistance rheological layer in the earths crust, and preexisting mechanical fragile zones. The epicenters located mainly in middleupper crust of the intersection between the three sides and the active faults. The minimum interval between two earthquakes was 215± years. The continued push from the Indian plate was the dynamic sources inducing such a large earthquake, whereas the sunspot activity and the change in autorotation rate of the earth may be the triggered factors for the earthquake. The 2001 Kunlun large earthquake and 2008 Wenchuan large earthquake may be the symbol mark suggesting that the triangle seismic zone in Central Asia has entered a new active period of 1075 years. If that is true, the large earthquakes ranging from M≥70 to M≥80 may occur potentially around the three sides of the triangle in the future decades.

Key words: Wenchuan large earthquake, triangle seismic zone in Central Asia, mechanical fragile zone, tectonic stress field, slip line field, media mechanical conditions, low resistance rheological layer in the crust