THE SEISMIC GAP PATTERN BEFORE THE LINFEN 7.5 EARTHQUKAKE, SHANXI PROVINCE IN 1695

This paepr mainly discussed the seismicity patterns before the Linden 7.5 earthquake Shanxi Province based on hitorical seismic data, and found that seismic gap was the main characteristic prior to this earthquake.The paper first introduced the source of historical seismic data and the principle of usage; then determined the property of index of the seismic gap, discussed the development process of the gap and also analyzed the relationship between the Linfen 7.2 earthquake and the earthquakes occurred in its surrounding areas. It is concluded that the Linfen 7.5 earthquake is the product of a series of large earthquakes occurred in North China area. Beforevhe 7.2 earthquake, the tectonic Stress in Linfen Basin was highly concentrated and the development of Linfen seismic gap underwent about 350 years.Its process mainly included the variations of tectonic stress accumulation——strain accelaration——quirescence——release by earthquake and the development process of the seismicity pattera of this active place of strong earthquake which attracted great attention.