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本文讨论了利用国际部署加速度仪台网(IDA)的超长周期瑞雷波记录,反演震源参数的有关理论和方法.对于震源深度大于30km的地震,地震矩张量的五个元素都可以测定;对于浅源(h≤30km)地震,其中两个元素变为无解.本文以1984年5月21日南黄海浅源地震为例,研究了在浅震难题的情况下,如何更多地提取震源信息的问题,测定了主震的断层机制为:走向北35°西,倾角52°,滑动方向54°,地震矩为1.2×10~(18)N·m,压应力主轴方向为北74.4°东,是一个走向北北西的左旋逆断层.本文还阐述了分布源模型问题。结果表明,采用分布源与采用点源模型对南黄海这种中强地震反演结果的影响不大.分析了震源有限性问题,提出了进行修正的一种明确表达式.
In this paper, we discuss the theories and methods of inversion of source parameters using the ultra-long-period Rayleigh wave records from the International Deployment Acceleration Network (IDA). For all earthquakes with a focal depth greater than 30 km, all five elements of the seismic moment tensor (H≤30km) earthquakes, two of these elements become non-solution.In this paper, a case study of the South Yellow Sea shallow source earthquakes on May 21, 1984 was conducted to investigate how the earthquakes The focal mechanism of the main shock was determined to be 35 ° north west, 52 ° dip angle, 54 ° slip direction, and the seismic moment was 1.2 × 10 ~ (18) N · m. The principal stress direction was 74.4 ° east to the north, a left-lateral thrust fault going north and west. This paper also expounds the problem of distributed source model. The results show that the distribution source and the point source model have little effect on the inversion results of the medium-strong earthquake in the southern Yellow Sea.Analyzed the finite-source problem and proposed an explicit expression for correction.