盈江地区构造应力场和断层识别的联合迭代式反演研究

Joint iterative inversion of tectonic stress field and fault identification in Yingjiang area

  • 摘要: 搜集了盈江及其邻区5组地震序列震源机制解并反演得到该区域的构造应力场。研究结果显示:盈江地区整体主压应力以NNE向为主,主张应力以ESE向为主;但其局部应力场不完全一致,沿苏典断裂分布的主压应力轴走向随着断裂走向由北向南延伸角度逐渐向北偏移,而盈江地区的西南部,其主压应力走向更偏向于东,这可能与大盈江断裂的横向拉伸有关。此外,本研究通过应力场反演识别出了5组地震序列震源机制解的主发震断层节面的走向、倾角、滑动角及发震断层的摩擦系数,为今后该区域的地震研究及地壳动力学变迁提供了参考。

     

    Abstract: There has always been a problem in inversion of tectonic stress field by focal mechanism solution, it is impossible to determine which nodel plane is the correct seismogenic fault plane. The joint iterative stress inversion method can effectively avoid the error caused by incorrect fault selection by identifying the fault instability. In this paper, the focal mechanism solutions of five groups of earthquake sequences in Yingjiang and its adjacent areas are collected, and the tectonic stress field in this area is inversed. The results show that, in Yingjiang area, the main compressive stress is NNE, and the main tensile stress is ESE, which is basically consistent with the previous research results. However, the local stress field is not completely consistent. The strike of the principal stress axis along the Sudian fault extends from north to south, and the angle gradually shifts to the north. In the southwest of Yingjiang, the strike of the principal stress tends to the East, which may be related to the transverse extension of the Dayingjiang fault. In addition, the strike, dip angle, slip angle and friction coefficient of the main seismogenic fault nodal planes of the focal mechanism solutions of five groups of earthquake sequences are identified by stress field inversion. This provides a valuable reference for the future seismic and crustal dynamic changes research in this region.

     

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