CAJ | 학술논문

在构造应力场的制约下强震孕育过程中特定阶段, 震源区中小地震震源机制与构造应力场的方向大体一致, 根据这一特点, 定义各个震源机制解的P轴, B轴, T轴和构造应力场的3个应力主轴在3维空间的夹角之和为一致性参数a, 研究强震前应力场变化特征. 对2006年11月15日千岛岛弧M_W8.3地震和2001年6月23日秘鲁M_W8.4地震研究表明, 大震发生前孕震区一致性参数a比较低, 震源机制与构造应力场的差异较小, 说明这些前震受到了震源区应力场的统一作用, 而主震发生之后震源机制解的一致性参数比较高, 说明后续发生的地震的震源机制散乱, 表明背景应力场的控制作用开始减弱.
재구조응력장적제약하강진잉육과정중특정계단, 진원구중소지진진원궤제여구조응력장적방향대체일치, 근거저일특점, 정의각개진원궤제해적P축, B축, T축화구조응력장적3개응력주축재3유공간적협각지화위일치성삼수a, 연구강진전응력장변화특정. 대2006년11월15일천도도호M_W8.3지진화2001년6월23일비로M_W8.4지진연구표명, 대진발생전잉진구일치성삼수a비교저, 진원궤제여구조응력장적차이교소, 설명저사전진수도료진원구응력장적통일작용, 이주진발생지후진원궤제해적일치성삼수비교고, 설명후속발생적지진적진원궤제산란, 표명배경응력장적공제작용개시감약.
At some stage of earthquake preparation, the focal mechanisms of small and medium-sized earthquake have roughly the same direction with the tectonic stress field. According to this feature, we define the angle between P, B, and T axises of focal mechanisms and three stress axises of tectonic stress field as the consistency parameter a, to research the dynamic changes of stress field in earthquake preparation area before strong earthquakes. In this paper, we mainly studied the changes of the consistency parameter a of the Kuril island arc M_W8.3 earthquake and Peru M_W8.4 earthquake. Our study found that before strong earthquake occurred, the focal mechanisms of a series of small and medium-sized earthquakes get small differences with the tectonic stress field, this indicates that those foreshocks are under the control of stress field, the focal mechanisms of shocks occurred at this time have the same direction with tectonic stress field; while the higher consistency means that the focal mechanisms of aftershocks are scattered, and have big difference with tectonic field, which means the control of background stress field start weakening.