A fault model with variable slip duration for the 1989 Loma Prieta, California, earthquake determined from strong-ground-motion data

Abstract A finite-fault model with variable slip duration is inferred from strong-ground-motion data for the Loma Prieta earthquake. Unlike previous models, slip duration is found to be consistent with fault width scaling. Slip duration varies between 1 and 6 sec at points along the fault surface with values between 3 and 6 sec, where slip amplitudes obtain or exceed the average slip of 98 cm. Modest high-frequency modifications of the slip function shape greatly enhance the data fit without significantly changing the inferred static offset or rupture characteristics. This model exhibits bilateral rupture with the propagation rate of the main energy release of 3 km/sec or less. The moment is 2.3 × 10 26 dyne-cm, and the largest slip amplitudes occur northwest of the hypocenter. The rake varies with position along the fault from dominantly strike slip in the southeast to dominantly reverse slip in the northwest.

[1]  Wei-Jou Su,et al.  Effects of three-dimensional crustal structure on the estimated slip history and ground motion of the Loma Prieta earthquake , 1994 .

[2]  Christopher H. Scholz,et al.  Scaling laws for large earthquakes: Consequences for physical models , 1982 .

[3]  William L. Ellsworth,et al.  The October 17, 1989, Loma Prieta, California, Earthquake and its aftershocks: Geometry of the sequence from high-resolution locations , 1990 .

[4]  T. Heaton.  Evidence for and implications of self-healing pulses of slip in earthquake rupture , 1990 .

[5]  Keiiti Aki,et al.  Mapping of the high-frequency source radiation for the Loma Prieta Earthquake, California , 1993 .

[6]  Gregory C. Beroza,et al.  Near-source modeling of the Loma Prieta earthquake: Evidence for heterogeneous slip and implications for earthquake hazard , 1991 .

[7]  D. J. Andrews,et al.  Bulletin of the Seismological Society of America , 1985 .

[8]  Jamison H. Steidl,et al.  Rupture history of the 1989 Loma Prieta, California, earthquake , 1991, Bulletin of the Seismological Society of America.

[9]  R. Madariaga.  Dynamics of an expanding circular fault , 1976, Bulletin of the Seismological Society of America.

[10]  Aaron A. Velasco,et al.  A broadband seismological investigation of the 1989 Loma Prieta, California, earthquake: Evidence for deep slow slip? , 1991 .

[11]  John G. Anderson,et al.  Implications of frequency-domain inversion of earthquake ground motions for resolving the space-time dependence of slip on an extended fault , 1988 .

[12]  Thomas H. Heaton,et al.  Rupture model of the 1989 Loma Prieta earthquake from the inversion of strong-motion and broadband teleseismic data , 1991, Bulletin of the Seismological Society of America.

[13]  A norm minimization criterion for the inversion of earthquake ground motion , 1990 .

[14]  R. J. Apsel,et al.  On the Green's functions for a layered half-space. Part II , 1983 .

[15]  Allen H. Olson.  A Chebyshev condition for accelerating convergence of iterative tomographic methods-solving large least squares problems , 1987 .

[16]  John G. Anderson,et al.  The temporal and spatial evolution of the 19 September 1985 Michoacán earthquake as inferred from near-source ground-motion records , 1991 .

[17]  Steven M. Day,et al.  DYNAMIC RUPTURE IN A LAYERED MEDIUM: THE 1966 PARKFIELD EARTHQUAKE , 1980 .