Resolving Fine-Scale Heterogeneity of Co-seismic Slip and the Relation to Fault Structure

Fault slip distributions provide important insight into the earthquake process. We analyze high-resolution along-strike co-seismic slip profiles of the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes, finding a spatial correlation between fluctuations of the slip distribution and geometrical fault structure. Using a spectral analysis, we demonstrate that the observed variation of co-seismic slip is neither random nor artificial, but self-affine fractal and rougher for Landers. We show that the wavelength and amplitude of slip variability correlates to the spatial distribution of fault geometrical complexity, explaining why Hector Mine has a smoother slip distribution as it occurred on a geometrically simpler fault system. We propose as a physical explanation that fault complexity induces a heterogeneous stress state that in turn controls co-seismic slip. Our observations detail the fundamental relationship between fault structure and earthquake rupture behavior, allowing for modeling of realistic slip profiles for use in seismic hazard assessment and paleoseismology studies.

[1]  Jean-Philippe Avouac,et al.  Coseismic surface deformation from air photos: The Kickapoo step over in the 1992 Landers rupture , 2006 .

[2]  François Renard,et al.  Constant dimensionality of fault roughness from the scale of micro‐fractures to the scale of continents , 2013 .

[3]  Robert C. Jachens,et al.  Relationship of the 1999 Hector Mine and 1992 Landers Fault Ruptures to Offsets on Neogene Faults and Distribution of Late Cenozoic Basins in the Eastern California Shear Zone , 2002 .

[4]  David T. Sandwell,et al.  The 1999 (Mw 7.1) Hector Mine, California, Earthquake: Near-Field Postseismic Deformation from ERS Interferometry , 2002 .

[5]  S. McGill,et al.  Surficial slip distribution on the central Emerson fault during the June 28 , 1999 .

[6]  O. Kreylos,et al.  Coseismic slip variation assessed from terrestrial lidar scans of the El Mayor–Cucapah surface rupture , 2013 .

[7]  K. Aki,et al.  Fractal geometry in the San Andreas Fault System , 1987 .

[8]  William A. Bryant,et al.  Primary Surface Rupture Associated with the Mw 7.1 16 October 1999 Hector Mine Earthquake, San Bernardino County, California , 2002 .

[9]  P. M. Mai,et al.  Evidence for self-similar, triangular slip distributions on earthquakes: Implications for earthquake and fault mechanics. , 2005 .

[10]  Sebastien Leprince,et al.  Co-registration and correlation of aerial photographs for ground deformation measurements , 2009 .

[11]  Yuri Fialko,et al.  Evidence of fluid-filled upper crust from observations of postseismic deformation due to the 1992 Mw7.3 Landers earthquake , 2004 .

[12]  Jeremy E. Kozdon,et al.  Earthquake Ruptures with Strongly Rate-Weakening Friction and Off-Fault Plasticity, Part 2: Nonplanar FaultsEarthquake Ruptures with Rate-Weakening Friction and Off-Fault Plasticity, Part 2: Nonplanar Faults , 2011 .

[13]  Kenneth W. Hudnut,et al.  Fault‐Slip Distribution of the 1999 Mw 7.1 Hector Mine Earthquake, California, Estimated from Postearthquake Airborne LiDAR Data , 2015 .

[14]  D. Thomson,et al.  Spectrum estimation and harmonic analysis , 1982, Proceedings of the IEEE.

[15]  Sébastien Leprince,et al.  Automatic and Precise Orthorectification, Coregistration, and Subpixel Correlation of Satellite Images, Application to Ground Deformation Measurements , 2007, IEEE Transactions on Geoscience and Remote Sensing.

[16]  A. Elliott,et al.  Evidence from coseismic slip gradients for dynamic control on rupture propagation and arrest through stepovers , 2009 .

[17]  Thomas K. Rockwell,et al.  Surface Rupture and Slip Distribution of the 1940 Imperial Valley Earthquake, Imperial Fault, Southern California: Implications for Rupture Segmentation and Dynamics , 2013 .

[18]  Yann Klinger,et al.  Evidence for an earthquake barrier model from Mw ∼ 7.8 Kokoxili (Tibet) earthquake slip-distribution , 2005 .

[19]  Steven G. Wesnousky,et al.  Seismological and structural evolution of strike-slip faults , 1988, Nature.

[20]  Y. Klinger.  continental strike-slip earthquake segmentation and thickness of the crust , 2010 .

[21]  D. Lockner.  A generalized law for brittle deformation of Westerly granite , 1998 .

[22]  D. Wells,et al.  New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement , 1994, Bulletin of the Seismological Society of America.

[23]  Robert Langridge,et al.  Lateral Offsets on Surveyed Cultural Features Resulting from the 1999 İzmit and Düzce Earthquakes, Turkey , 2002 .

[24]  C. Kesselman,et al.  CyberShake: A Physics-Based Seismic Hazard Model for Southern California , 2011 .

[25]  Jerome A. Treiman,et al.  Near-Field Investigations of the Landers Earthquake Sequence, April to July 1992 , 1993, Science.

[26]  Giuseppe Cello,et al.  Fractal analysis of a Quaternary fault array in the central Apennines, Italy , 1997 .

[27]  I. Manighetti,et al.  Generic along‐strike segmentation of Afar normal faults, East Africa: Implications on fault growth and stress heterogeneity on seismogenic fault planes , 2015 .

[28]  J. Dieterich,et al.  Nonplanar Faults: Mechanics of Slip and Off-fault Damage , 2009 .

[29]  E. Dunham,et al.  Earthquake Ruptures with Strongly Rate-Weakening Friction and Off-Fault Plasticity, Part 1: Planar Faults , 2011 .

[30]  J. Avouac,et al.  Deformation due to the 17 August 1999 Izmit, Turkey, earthquake measured from SPOT images , 2002 .

[31]  C. Collettini,et al.  Faults smooth gradually as a function of slip , 2011 .

[32]  Amir Sagy,et al.  Evolution of fault-surface roughness with slip , 2007 .

[33]  G. Beroza,et al.  A spatial random field model to characterize complexity in earthquake slip , 2002 .

[34]  T. Rockwell,et al.  Southern San Andreas Fault Evaluation Field Activity: Approaches to Measuring Small Geomorphic Offsets—Challenges and Recommendations for Active Fault Studies , 2014 .

[35]  S. Day,et al.  Rupture dynamics and ground motion from 3‐D rough‐fault simulations , 2013 .

[36]  P. Mai,et al.  Implications for earthquake and fault mechanics , 2005 .

[37]  P. Rosen,et al.  SYNTHETIC APERTURE RADAR INTERFEROMETRY TO MEASURE EARTH'S SURFACE TOPOGRAPHY AND ITS DEFORMATION , 2000 .

[38]  Sebastien Leprince,et al.  Quantifying near‐field and off‐fault deformation patterns of the 1992 Mw 7.3 Landers earthquake , 2015 .

[39]  Kerry E Sieh,et al.  The transfer of slip between two en echelon strike‐slip faults: A case study from the 1992 Landers earthquake, southern California , 1995 .