关键词: 地震类型, 区域加载场, 局部变形响应, 应力路径和应变路径, 断层稳定性判别

Abstract: In the present paper, double shear stick-slip model experiments were conducted for simulating the regional loading process of spontaneous earthquake and induced earthquake, and a strain observation system was employed to acquire dada continuously to monitor the local strain changes near fault under the loading process. Regional stress path and local strain path during the whole earthquake process have been described on the stress space and strain space. Though the morphology of local strain path is different greatly from the macroscopical stress path, there is a certain mapping relation on the corresponding transformation stages between stress path and strain path. The evolution trend of local strain path indicates the possible stage of the fault deformation. The strain path of spontaneous earthquake can be divided into three parts: Strain accumulation, linear deviation of shear strain and unstable slip. The strain path of induced earthquake includes four stages: Strain accumulation with positive slope, steady state slip with negative slope, metastable strain stalemate and unstable slip under a disturbance. Spontaneous earthquake and induced earthquake have their own inherent and steady path model, so the fault stability and the possible earthquake type could be judged according to the special strain path.

Key words: earthquake model, regional loading field, local deformation response, stress path and strain path, fault stability criterion