Coseismic fault slip associated with the 1992 M w 6.1 Joshua Tree, California, earthquake: Implications for the Joshua Tree-Landers earthquake sequence

Coseismic surface deformation associated with the Mw 6.1, April 23, 1992, Joshua Tree earthquake is well represented by estimates of geodetic monument displacements at 20 locations independently derived from Global Positioning System and trilateration measurements. The rms signal to noise ratio for these inferred displacements is 1.8 with near-fault displacement estimates exceeding 40 mm. In order to determine the long-wavelength distribution of slip over the plane of rupture, a Tikhonov regularization operator is applied to these estimates which minimizes stress variability subject to purely right-lateral slip and zero surface slip constraints. The resulting slip distribution yields a geodetic moment estimate of 1.7 × 1018 N m with corresponding maximum slip around 0.8 m and compares well with independent and complementary information including seismic moment and source time function estimates and main shock and aftershock locations. From empirical Green's function analyses, a rupture duration of 5 s is obtained which implies a rupture radius of 6–8 km. Most of the inferred slip lies to the north of the hypocenter, consistent with northward rupture propagation. Stress drop estimates are in the range of 2–4 MPa. In addition, predicted Coulomb stress increases correlate remarkably well with the distribution of aftershock hypocenters; most of the aftershocks occur in areas for which the mainshock rupture produced stress increases larger than about 0.1 MPa. In contrast, predicted stress changes are near zero at the hypocenter of the Mw 7.3, June 28, 1992, Landers earthquake which nucleated about 20 km beyond the northernmost edge of the Joshua Tree rupture. Based on aftershock migrations and the predicted static stress field, we speculate that redistribution of Joshua Tree-induced stress perturbations played a role in the spatio-temporal development of the earthquake sequence culminating in the Landers event.

[1]  Steven N. Ward,et al.  An inversion for slip distribution and fault shape from geodetic observations of the 1983, Borah Peak, Idaho, Earthquake , 1986 .

[2]  D. Wald,et al.  Spatial and temporal distribution of slip for the 1992 Landers, California, earthquake , 1994, Bulletin of the Seismological Society of America.

[3]  R. Sibson.  Fault zone models, heat flow, and the depth distribution of earthquakes in the continental crust of the United States , 1982 .

[4]  Sean C. Solomon,et al.  Geodetic measurement of deformation in the central Mojave Desert, California , 1986 .

[5]  Ari Ben-Menahem,et al.  Crustal deformation by earthquakes and explosions , 1970, Bulletin of the Seismological Society of America.

[6]  S. Hough,et al.  Southern surface rupture associated with the 1992 M7.4 Landers Earthquake: Did it all happen during the mainshock? , 1993 .

[7]  M. A. Chinnery.  The deformation of the ground around surface faults , 1961 .

[8]  M. A. Chinnery,et al.  Elastic Dislocations in a Layered Half‐Space–II The Point Source , 1974 .

[9]  Stephen H. Hartzell,et al.  INVERSION FOR SLIP DISTRIBUTION USING TELESEISMIC P WAVEFORMS: NORTH PALM SPRINGS, BORAH PEAK, AND MICHOACAN EARTHQUAKES , 1988 .

[10]  Y. Okada.  Surface deformation due to shear and tensile faults in a half-space , 1985 .

[11]  M. Clark.  Map showing recently active breaks along the San Andreas fault and associated faults between Salton Sea and Whitewater River-Mission Creek, California , 1984 .

[12]  Roy K. Dokka,et al.  Late Cenozoic strike-slip faulting in the Mojave Desert, California , 1990 .

[13]  J. C. Savage.  Effect of crustal layering upon dislocation modeling , 1987 .

[14]  K. Sieh,et al.  Behavior of the southernmost San Andreas Fault during the past 300 years , 1990 .

[15]  Kurt L. Feigl,et al.  Space geodetic measurement of crustal deformation in central and southern California , 1993 .

[16]  J. C. Savage,et al.  Surface deformation associated with dip‐slip faulting , 1966 .

[17]  Deformation from 1973 through 1991 in the epicentral area of the 1992 Landers, California, Earthquake (Ms = 7.5) , 1993 .

[18]  D. E. Smylie,et al.  The displacement fields of inclined faults , 1971, Bulletin of the Seismological Society of America.

[19]  Ross S. Stein,et al.  The 1979 Homestead Valley Earthquake Sequence, California: Control of Aftershocks and Postseismic Deformation , 1983 .

[20]  J. C. Savage,et al.  Coseismic displacements: 1992 Landers, California, Earthquake , 1993 .

[21]  G. King,et al.  STATIC STRESS CHANGES AND THE TRIGGERING OF EARTHQUAKES , 1994 .

[22]  Ari Ben-Menahem,et al.  Multipolar elastic fields in a layered half space , 1968 .

[23]  A. Ben-menahem,et al.  Deformation of a homogeneous Earth model by finite dislocations , 1970 .

[24]  G. Backus,et al.  The Resolving Power of Gross Earth Data , 1968 .

[25]  E. Hauksson,et al.  The 1992 Landers Earthquake Sequence: Seismological observations , 1993 .

[26]  P. Segall,et al.  Comparison of various inversion techniques as applied to the determination of a geophysical deformation model for the 1983 Borah Peak earthquake , 1992, Bulletin of the Seismological Society of America.

[27]  C. R. Allen,et al.  The Desert Hot Springs earthquakes and their tectonic environment , 1958 .

[28]  J. C. Savage,et al.  An apparent shear zone trending north-northwest across the Mojave Desert into Owens Valley, eastern , 1990 .

[29]  D. Dong.  The horizontal velocity field in southern California from a combination of terrestrial and space-geodetic data , 1993 .

[30]  G. Lindley.  Source parameters of the 23 April 1992 Joshua Tree, California, earthquake, its largest foreshock, and aftershocks , 1994 .

[31]  Christopher H. Scholz,et al.  The brittle-plastic transition and the depth of seismic faulting , 1988 .

[32]  J. Steketee,et al.  SOME GEOPHYSICAL APPLICATIONS OF THE ELASTICITY THEORY OF DISLOCATIONS , 1958 .

[33]  A. Aydin,et al.  Stress transfer during three sequential moderate earthquakes along the central Calaveras Fault, California , 1993 .

[34]  Paul G. Richards,et al.  Quantitative Seismology: Theory and Methods , 1980 .

[35]  Roy K. Dokka,et al.  Role of the Eastern California Shear Zone in accommodating Pacific‐North American Plate motion , 1990 .

[36]  David R. Brillinger,et al.  A more precise chronology of earthquakes produced by the San Andreas fault in southern California , 1989 .

[37]  Jian Lin,et al.  Change in Failure Stress on the Southern San Andreas Fault System Caused by the 1992 Magnitude = 7.4 Landers Earthquake , 1992, Science.

[38]  Shawn Larsen,et al.  Global positioning system measurements of deformations associated with the 1987 Superstition Hills earthquake - Evidence for conjugate faulting , 1992 .

[39]  J. Steketee.  ON VOLTERRA'S DISLOCATIONS IN A SEMI-INFINITE ELASTIC MEDIUM , 1958 .

[40]  Sarva Jit Singh.  Static deformation of a multilayered half‐space by internal sources , 1970 .

[41]  L. Sykes,et al.  Great earthquakes and great asperities, San Andreas fault, southern California , 1985 .

[42]  G. Wahba.  Spline models for observational data , 1990 .

[43]  Thomas H. Heaton,et al.  Inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 Imperial Valley, California, earthquake , 1983 .

[44]  M. A. Chinnery,et al.  Elastic Dislocations in a Layered Half-Space—I. Basic Theory and Numerical Methods , 1974 .

[45]  P. Segall,et al.  Earthquake deformation cycle on the San Andreas Fault near Parkfield, California , 1987 .