固体潮应力张量对地震的触发作用
TRIGGERING OF EARTHQUAKES BY THE TIDAL STRESS TENSOR
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摘要: 用无体力作用的平衡方程的型、型通解与有体力作用的平衡方程的特解相迭加得到自由边界条件下的潮汐应力张量.讨论了主应力和主应力轴随深度的变化, 在100公里的深度范围内, 主应力轴在空间的取向发生的偏转可达10左右(=30时).选用我国195~(?)年以来有精确断层面解的、Ms5.0的70个地震的资料, 研究了发震时刻对于潮汐流体静应力、潮汐最大剪应力、沿断层错动矢量的潮汐剪应力的位相分布.所得的结论是, 潮汐流体静应力与地震的发震时刻没有明显关系.潮汐最大剪应力对地震有一定的触发作用;沿断层错动矢量的潮汐剪应力对地震的触发作用更明显些;斜滑型地震对潮汐最大剪应力的位相有极好的相关性.Abstract: By superimposing the -and -type general solutions of the equilibrium equation without body force and particular solution of the equilibrium with tidal body force, the tidal stress tensor under free boundary conditions is obtained, and the change of the prineipal stresses and principal stress axes with depth is discussed. In the depth range 0-100km, the deviation of the direction of the principal stress axes in space, may reach a value as high as 10(when =30).The phase distributions of tidal hydrostatic stress, the maximum tidal shear stress and the tidal shear stress along the dislocation vectors of the faults as related to the origin times of the earthquakes have been studied for 70 earthquakes (Ms5.0) occurred in our country since 1957, having correct fault plane solutions.There is no apparent correlation between the phase of tidal, hydrostatic stress and the origin time of the earthquake (pr=0.58), but the maximum tidal shear stress has a certain effect on the triggering of the earthquakes (pr=8.110-2). Tidal shear stress along the dislocation vectors of faults plays an even more prominant part (pr=5.210-2). The phase of the maximum shear stress correlates well with the earthquakes of the oblique-slip type (pr=8.710-4).
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[1] L. .Knopoff, Fartli tides as a triggering mechanism Por eartLqnahes, Bull. Selsm, Soc. Am., 54, 1865——1870. 1964.
[2] A. Ryall, J. D. Van Wormcr, & A. L. Jones, Triggering of microcarthqnakes by earth tides, and other features of the Truckee, California, earthquake serlneuces of September, 1966. Bull. Seism. Soc. Am., 58, 215——298, 1968.
[3] J. F. Simpsou, Earth tides as a triggering mechanism for earthquakes, Earth and Planetary Sci. Letters, 2. 5, 473——478, 1957.
[4] T. H. Heaton, Tidal triggering of earthquakes, Geophy. J. R, astr. Soc., 43, 307——323, 1975.
[5] S. Shlien, Earthquake——tide correlation. Geophy. J. R, astr. Soc., 28, 27——34, 1972.
[6] E. W. Kleim, Earthquake swarms and the scmidiurual solid earth tide, Geophys. J. R. astr, Soc., 45, 245——295. 1976.
[7] D. E. Willis, & R. W, Taylor, Investigation of multiple seismie events and first zone diseriminants, ARPA Semi——Annual Teclinical Eeport, April 1974. Caltech
[8] 钱伟长、叶开源, 弹性力学, 科学出版社, 1956.
[9] P. hlelvhior, The tides of t.hc Planet Earth, 7918
[10] 中国科学院沈阳计算所等, 电子计算机常用算法。科学出版社, 1976
[11] M. N, Toksöz. Moonquake: Mechanisms and relation to tidal stresses, Seince, 196, 4293, 979——981, 1977
[12] 中国科学院地球物理所第三研究室实验组, 单轴压力下岩石破裂的初步研究, 地球物理学报, 19, 4, 306——316, 1976.[1] L. .Knopoff, Fartli tides as a triggering mechanism Por eartLqnahes, Bull. Selsm, Soc. Am., 54, 1865——1870. 1964.
[2] A. Ryall, J. D. Van Wormcr, & A. L. Jones, Triggering of microcarthqnakes by earth tides, and other features of the Truckee, California, earthquake serlneuces of September, 1966. Bull. Seism. Soc. Am., 58, 215——298, 1968.
[3] J. F. Simpsou, Earth tides as a triggering mechanism for earthquakes, Earth and Planetary Sci. Letters, 2. 5, 473——478, 1957.
[4] T. H. Heaton, Tidal triggering of earthquakes, Geophy. J. R, astr. Soc., 43, 307——323, 1975.
[5] S. Shlien, Earthquake——tide correlation. Geophy. J. R, astr. Soc., 28, 27——34, 1972.
[6] E. W. Kleim, Earthquake swarms and the scmidiurual solid earth tide, Geophys. J. R. astr, Soc., 45, 245——295. 1976.
[7] D. E. Willis, & R. W, Taylor, Investigation of multiple seismie events and first zone diseriminants, ARPA Semi——Annual Teclinical Eeport, April 1974. Caltech
[8] 钱伟长、叶开源, 弹性力学, 科学出版社, 1956.
[9] P. hlelvhior, The tides of t.hc Planet Earth, 7918
[10] 中国科学院沈阳计算所等, 电子计算机常用算法。科学出版社, 1976
[11] M. N, Toksöz. Moonquake: Mechanisms and relation to tidal stresses, Seince, 196, 4293, 979——981, 1977
[12] 中国科学院地球物理所第三研究室实验组, 单轴压力下岩石破裂的初步研究, 地球物理学报, 19, 4, 306——316, 1976.
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