Focal Mechanism of Small Earthquakes and Characteristics of Tectonic Stress Field in South China

摘要

The focal mechanism of 200 small earthquakes in South China were determined by means of P and S amplitude ratios.The result indicates that P-axes of the recent tectonic stress field are characterized by a fan-shaped distribution.From the west to the east of the region,the P-axes concentrate on NNE-NW-NWW.T-axes of the recent tectonic stress field are characterized by an arc-shaped distribution.From Guangxi to Fujian Province along the coast,the T-axes concentrate on NWW-NEE-NNE.The average P-axes and T-axes are nearly horizontal.