Sawtooth segmentation and deformation processes on the southern San Andreas Fault, California

Five contiguous 12-13 km fault segments form a sawtooth geometry on the south- ernmost San Andreas fault. The kinematic and morphologic properties of each segment depend on fault strike, despite differences of strike between segments of as little as 3 degrees. Oblique slip (transpression) of fault segments within the Indio Hills, Mecca Hills and Durmid Hill results from an inferred 8:1 ratio of dex- tral slip to convergence across the fault zone. Triggered slip and creep are confined almost en- tirely to transpressive segments of the fault. Durmid Hill has been formed in the last 28 n 6 ka by uplift at an average rate of 3  1 mm/a.

[1]  L. Sykes,et al.  "Probabilities of occurrence of large plate rupturing earthquakes for the San Andreas, San Jacinto, and Imperial faults, California,1983–2003"" , 1984 .

[2]  P. Bird,et al.  Kinematics of present crust and mantle flow in southern California , 1984 .

[3]  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 .

[4]  Thomas H. Jordan,et al.  Present‐day plate motions , 1977 .

[5]  J. C. Savage.  STRAIN ACCUMULATION IN WESTERN UNITED STATES , 1983 .

[6]  A. Sylvester,et al.  Tectonic Transpression and Basement-Controlled Deformation in San Andreas Fault Zone, Salton Trough, California , 1976 .

[7]  GEOFFREY KING,et al.  Role of Fault Bends in the Initiation and Termination of Earthquake Rupture , 1985, Science.

[8]  K. Sieh.  Slip Along the San Andreas Fault Associated with the Earthquake , 1982 .

[9]  J. Jackson,et al.  Relations between surface deformation, fault geometry, seismicity, and rupture characteristics during the El Asnam (Algeria) earthquake of 10 October 1980 , 1981 .

[10]  R. J. Shlemon,et al.  Tectonic geomorphology of the San Andreas fault zone in the southern Indio Hills, Coachella Valley, California , 1982 .

[11]  E. A. Babcock.  Geology of the Northeast Margin of the Salton Trough, Salton Sea, California , 1974 .

[12]  J. C. Savage,et al.  Strain‐rate profile across the Elsinore, San Jacinto, and San Andreas Faults near Palm Springs, California, 1973‐81 , 1983 .

[13]  C. R. Allen,et al.  Fault slip in southern California , 1985 .

[14]  G. King,et al.  Seismic Potential Revealed by Surface Folding: 1983 Coalinga, California, Earthquake , 1984, Science.