The regional characteristics of seismic activity in China

Abstract

In this paper, the regional characteristics of seismicity of strong earthquakes in 27 seismic provinces in the whole China were discussed. It is divided into 5 kinds of regions on the basis of analyzing the earthquake’s annual average rate ofM⩾6,b-value and the maximum magnitude in history in those provinces. Among them, the seismic activity in the eastern part of Taiwan seismic province is the highest, where the annual average rate of earthquake occurrencevM⩾6 is more than 1. The second kind region includes Pamir, south and north Tianshan, Yunnan-Sichuan, west Kunlun, Himalaya and western part of Taiwanetc. 9 seismic provinces,vM⩾6 are 0.12–0.34. The third kind of regions contains 10 seismic provinces, such as 4 provinces in North China, northeast border of Qingzang (Qinghai-Xiang) plateau, Gobi-Altay and the outside southeast coast provinceetc., wherevM⩾6=0.332 − 0.08, the maximum earthquakes ofMmax ⩾ 8 were recorded in the history in most seismic provinces of the region, only a few seismic provinces recordedMmax = 7.3 − 7.5. The fourth kind of regions include 6 seismic provinces, such as the northeast China, the middle and lower reaches of the Yangtze River and South Chinaetc., where,vM⩾6=0.01 − 0.03, the largest earthquake recorded in the history isMmax<7. The fifth kind of regions is the one with the lowest seismic activities,Mmax=5 ¾ be recorded as the maximum magnitude there. The regional characteristics of the strong earthquake activity have close relationship with tectonic movement of the surrounding plate and of the introplate block.