Abstract:
This study analyzed the seismicity image of South China before the 2016
Ms5.4 Cangwu earthquake and the temporal and spatial variation of apparent stress of small earthquakes near the epicenter and can obtain the following conclusions. Before the Cangwu Earthquake, there are phenomena which are "small earthquakes increased - small earthquakes continued to be active-small earthquakes were relatively quiet-moderately strong earthquakes" within 250 km of epicenter. In northwest Guangxi, the seismic activity above
Ms3.0 become active, and its seasonal frequency reaches 4 times. From 2012 to 2016, moderate earthquake migration and enhanced activity of small earthquake swarms have occurred in South China. The increase of differential apparent stress in two years before the Cangwu earthquake is in good synchrony with the increased seismic activity of small earthquakes near the epicenter, the increased seismic activity of
Ms3.0 earthquakes in Northwest Guangxi and the migration of moderate earthquakes in South China. The evolution of various seismicity images is a concomitant phenomenon of regional stress enhancement. The Cangwu earthquake occurred in the background of regional stress level enhancement.