Textual Research on the Historical Data of the 1573 AD Minxian Earthquake in Gansu Province and Discussion on Its Seismogenic Structure

摘要

According to the detailed study of the historical earthquake records and causative structure of the Minxian M6(1/2) earthquake in 1573 {A.D.}, we have found that the most grievous disaster area lies nearby the Minxian county seat (Minzhou county at that time). So, we have identified the extremely seismic area of the 1573 {A.D.} The Minxian M6(1/2) earthquake was located in Minxian city, the intensity of the meizoseismal region is Ⅷ～Ⅸ, the epicenter is 34.4°N, 104.0°E, the location precision is Ⅱ and the deviation of location is less than or equal to 25km. Tectonically, this area lies in the transition region of stress transfer and structural transform between the east Kunlun fault and the northern margin of the west Qinling fault. The differential activity of the Lintan-Dangchang fault zone is obvious, and only parts of the segment put up Holocene activity. There are landslides and rock bursts of different sizes in the meizoseismal region. By integrated analysis, we conclude that the Minxian-Dangchang segment of the Lintan-Dangchang fault is the seismogenic structure of the 1573 A.D. M6(1/2) Minxian earthquake, in Gansu Province.