Regionalization of recent tectonic stress field in China and strong earthquakes

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Xie, Furen; Cui, Xiaofeng; Zhang, Hongyan; Du, Yi
Holding Date 10 September 2008

According to the stress state and force source character, the recent tectonic stress field of China and adjacent is classified into four classes: The first order tectonic stress district is mostly controlled by geometry character of plate boundary and force acting on plate boundary, the stress action of this stress field shows uniformity and stability in large areas and long time. The stress action of second order tectonic stress district shows correlation with in large area. This stress field is controlled by regional block interaction. The stress regime of the third order tectonic stress district shows comparability in finite areas. This stress filed is mostly influenced by interior block interaction inside the areas. The stress character (direction, intensity, regime, etc) of the forth order stress district shows better coherence. This stress filed is mostly controlled by block and fault interaction, and some may be influenced by its crust structure and tectonic environment character. Recent tectonic stress field in China and adjacent is divided into two first order districts, four second order districts, five third order districts and twenty-six fourth order districts.
Through researching the relation between recent tectonic stress field and earthquake activity of China continent and adjacent area, we proved the close relations between strong earthquakes and recent tectonic stress in continental China by working out a map of recent tectonic stress fields in China. This relations include mainly:
(1) stress borders of the first rank, controlled by the plate tectonics, are concentrative zones of strong earthquakes,
(2) transformation zone of stress direction, regime or strength generally has strong earthquakes,
(3) local differentiation of an even stress background has strong earthquakes relatively concentrated,
(4) stress transformation zone along active faults is more likely to have strong earthquakes,
(5) area with high stress value has stronger earthquake activities.