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

摘要： 使用双剪粘滑模型模拟自发地震和诱发地震的区域加载过程，利用应变观测系统多点连续观测发震断层附近的局部应变变化。在应力与应变空间上描述了地震过程的区域应力路径和局部应变路径。结果表明，局部应变路径与应力宏观路径的形态差异较大，但两者的转换阶段对应，存在一定映射关系。断层局部变形路径的走向标明了断层所处在的变形阶段。自发地震的应变路径可以划分为3个部分：应变积累阶段、剪应变的线性偏离阶段和失稳滑动阶段。诱发地震的应变路径包括4个阶段：正斜率的应变积累阶段、负斜率的稳态滑动阶段、亚稳态应变僵持阶段、扰动失稳滑动阶段。自发地震与诱发地震有各自的路径模式，可以从应变路径上判别断层稳定性与可能的地震类型。

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