Showing papers by "Ajit Mal published in 1972"
TL;DR: In this article, the diffraction of normally incident compressional and antiplane shear waves by a Griffith crack in an infinite isotropic elastic medium is considered, and the stress intensity factors as well as the maximum crack openings are expressed in series of ascending powers of the normalized wave number.
24 citations
TL;DR: In this paper, the propagation of Love and Rayleigh waves along an approximately north-south section of the San Fernando Valley is studied by means of a recently developed finite element technique.
Abstract: By means of a recently developed finite element technique, the propagation of Love and Rayleigh waves along an approximately north-south section of the San Fernando Valley is studied. At periods of 1 sec or less, the surface amplitudes of both Love and Rayleigh waves increase considerably with distance south into the valley as the alluvium thickens. Dipping structures give rise to higher Love and Rayleigh modes which modulate the surface displacement caused by the fundamental Love and Rayleigh modes. At periods of 1 sec or less, the fundamental Love and Rayleigh modes travel almost entirely in the uppermost 9000 ft (2743 m) of the Earth9s crust. Conversion of the first higher Love mode to the fundamental mode can contribute significantly to the Love wave surface displacement. Finally, at periods of 1 sec or less, the phase velocities of the fundamental Love and Rayleigh modes depend on the displacements of these modes near the surface of the Earth. These velocities may be considerably different from the arithmetic mean of the phase velocities of the Love and Rayleigh modes at the ends of the model.
15 citations
TL;DR: The amplitude of the Rayleigh wave produced by a finite, propagating dip-slip fault of arbitrary orientation in a homogeneous, isotropic half-space is obtained in this paper.
Abstract: The amplitude of the Rayleigh waves produced by a finite, propagating dip-slip fault of arbitrary orientation in a homogeneous, isotropic half-space is obtained The fault is assumed to initiate suddenly at depth and to spread unilaterally to the free surface with constant speed The Rayleigh-wave amplitude ahead of the fault break is shown to be considerably higher than that behind the initial epicenter There is severe amplitude modulation in the epicentral region caused by the interference of waves traveling in opposite directions The numerical results indicate that for Rayleigh waves in the period range of interest in earthquake engineering, a number of simplifications can be made in modeling an earthquake source of this type
14 citations