Surface potential and gravity changes due to internal dislocations in a spherical earth—II. Application to a finite fault
Surface potential and gravity changes due to internal dislocations in a spherical earth—II. Application to a finite fault
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DOI：
10.1046/j.1365-246x.1998.00400.x
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发表时间：
2002-02
影响因子：
2.8
通讯作者：
Wenke Sun;S. Okubo
中科院分区：
文献类型：
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作者：
Wenke Sun;S. Okubo
本文提出了一种计算球对称地球中位错引起的弹性变形的数值公式。它是基于我们以前对点位错的工作（Sun & Okubo 1993）。该公式使我们能够计算位移，潜在的和重力的变化，由于地震模拟为空间分布的位错。作为断层错动理论的一个应用，我们对理论重力变化和观测重力变化进行了实例研究。计算结果与观测到的地震重力变化符合得很好。近场重力变化可达100伽左右，任何现代重力仪都能很容易地探测到。在远场，它们仍然很大：全球范围内，震中距离内的jdgj > 10 ]gal，震中距离内的h 1 ]gal，震中距离内的h 0：1 ]gal，震中距离内的h 0：01 ]gal。我们还计算了1964年阿拉斯加地震引起的大地水准面高度的变化，并与修改后的参数和假设的障碍，由同一地震。我们认为，地震引起的大地水准面高度变化应达1.5厘米。
SUMMARY We present a numerical formulation for computing elastic deformations caused by a dislocation on a ¢nite plane in a spherically symmetric earth. It is based on our previous work for a point dislocation (Sun & Okubo 1993). The formulation enables us to compute the displacement, potential and gravity changes due to an earthquake modelled as spatially distributed dislocations. As an application of the ¢nite-fault dislocation theory, we make a case study of the theoretical and observed gravity changes. The computed results are in excellent agreement with the observed gravity changes during the earthquake. The gravity changes in the near ¢eld can reach some 100 ]gal, which can be easily detected by any modern gravimeter. In the far ¢eld they are still signi¢cantly large:jdgj > 10 ]gal within the epicentral distance h 1 ]gal within h 0:1 ]gal within h 0:01 ]gal globally. We also calculate the geoid height changes caused by the 1964 Alaska earthquake and by the same earthquake with revised parameters and an assumed barrier. We ¢nd that the earthquake should have caused geoid height changes as large as 1.5 cm.