Deformation of a Homogeneous Earth Model by Finite Dislocations,

摘要

The deformation of a homogeneous,non-gravitating,elastic sphere induced by a finite displacement dislocation placed inside the sphere is obtained in the form of rapidly converging series for arbitrary value of the Poisson ratio. Surface displacements,tilts,strains,and stresses are computed for strike-slip and dip-slip source models with various vertical extents. The numerical results are mapped on an epicentral tangential plane. Assuming a strike-slip fault of length 600km extending from the free surface to a depth of 100km and with a dislocation of 20 m it is estimated that this would yield a strain of the order of 10to the minus 9th power at an equatorial station with respect to the source. The corresponding estimate for a dip-slip source is 10to the minus 11th power. However,for deeper sources the difference in the estimated values of the strains decreases. Thus the seismic events such as the Alaska earthquake of March 28, 1964,should produce strains large enough to be detected by modern extensometers and tiltmeters in the far field. (Author)