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J.W. Rudnicki

Publications and source records attributed to J.W. Rudnicki.

3 recordsLinked to original sources
USGS1996

The Loma Prieta, California, Earthquake of October 17, 1989: Main shock characteristics

The October 17, 1989, Loma Prieta, Calif., earthquake (0004:15.2 G.m.t. October 18; lat 37.036º N., long 121.883º W.; 19-km depth) had a local magnitude (M L ) of about 6.7, a surface-wave magnitude (M S ) of 7.1, a seismic moment of 2.2x10 19 N-m to 3.5x10 19 N-m, a source duration of 6 to 15 s, and an average stress drop of at least 50 bars. Slip occurred on a dipping fault surface about 35 km long and was largely confined to a depth of about 7 to 20 km. The slip vector had a large vertical component, and slip was distributed in two main regions situated northwest and southeast of the hypocenter. This slip distribution caused about half of the earthquake's energy to be focused toward the urbanized San Francisco Bay region, while the other half was focused toward the southeast. Had the rupture initiated at the southeast end of the aftershock zone, shaking in the bay region would have been both longer and stronger. These source parameters suggest that the earthquake was not a typical shallow San Andreas-type event but a deeper event on a different fault with a recurrence interval of many hundreds of years. Therefore, the potential for a damaging shallow event on the San Andreas fault in the Santa Cruz Mountains may still exist.

California↗
USGS1990

Plane-strain shear dislocations moving steadily in linear elastic diffusive solids

This paper derives the stress and pore pressure fields induced by a plane-strain shear (gliding edge) dislocation moving steadily at a constant speed V in a linear elastic, fluid-infiltrated (Biot) solid. Solutions are obtained for the limiting cases in which the plane containing the moving dislocation (y = 0) is permeable and impermeable to the diffusing species. Although the solutions for the permeable and impermeable planes are required to agree with each other and with the ordinary elastic solution in the limits of V = 0 (corresponding to drained response) and V = ∞ (corresponding to undrained response), the stress and pore pressure fields differ considerably for finite nonzero velocities. For the dislocation on the impermeable plane, the pore pressure is discontinuous on y = 0 and attains values which are equal in magnitude and opposite in sign as y = 0 is approached from above and below. The solution reveals the surprising result that the pore pressure on the impermeable plane is zero everywhere behind the moving dislocation (x < 0). For the dislocation on the permeable plane, the pore pressure is zero on y = 0 and attains its maximum at about (2c/V, 2c/V) where c is the diffusivity, and the origin of the coordinate system coincides with the dislocation. For the impermeable plane, the largest pore pressure change occurs at the origin.

Journal of Applied Mechanics↗