Coseismic and Postseismic Slip of the 2004 Parkfield Earthquake from Space-Geodetic Data

We invert interferometric synthetic aperture radar (insar) data jointly with campaign and continuous global positioning system (gps) data for slip in the coseismic and postseismic periods of the 2004 Parkfield earthquake. The insar dataset consists of eight interferograms from data collected by the Envisat and Radarsat satellites spanning the time of the earthquake and variable amounts of the postseismic period. The two datasets complement each other, with the insar providing dense sampling of motion in the range direction of the satellite and the gps providing more sparse, but three-dimensional measurements of ground motion. The model assumes exponential decay of the postseismic slip with a decay time constant of 0.087 years, determined from time series modeling of continuous gps and creepmeter data. We find a geodetic moment magnitude of M 6.2 for a 1-day coseismic model and M w 6.1 for the entire postseismic period. The coseismic rupture occurred mainly in two slip asperities; one near the hypocenter and the other 15–20 km north. Postseismic slip occurred on the shallow portions of the fault and near the rupture areas of two M 5.0 aftershocks. A comparison of the geodetic slip models with seismic moment estimates suggests that the coseismic moment release of the Parkfield earthquake is as little as 25% of the total. This underlines the importance of aseismic slip in the slip budget for the Parkfield segment. Online material: Complete data tables and supplemental tables.

[1]  H. Zebker,et al.  Sensing the ups and downs of Las Vegas: InSAR reveals structural control of land subsidence and aquifer-system deformation , 1999 .

[2]  K. Hudnut,et al.  Preliminary Report on the 22 December 2003, M 6.5 San Simeon, California Earthquake , 2004 .

[3]  Paul Segall,et al.  Testing time-predictable earthquake recurrence by direct measurement of strain accumulation and release , 2002, Nature.

[4]  W. Prescott,et al.  Inversion of GPS data for spatially variable slip‐rate on the San Andreas Fault near Parkfield, CA , 2001 .

[5]  M. Wyss,et al.  DISPLACEMENT ON THE SAN ANDREAS FAULT SUBSEQUENT TO THE 1966 PARKFIELD EARTHQUAKE , 1968 .

[6]  W. H. Bakun,et al.  The Parkfield, California, Earthquake Prediction Experiment , 1985, Science.

[7]  W. H. Bakun,et al.  Implications for prediction and hazard assessment from the 2004 Parkfield earthquake , 2005, Nature.

[8]  R. Bürgmann,et al.  Coseismic slip distribution of the 2003 Mw 6.6 San Simeon earthquake, California, determined from GPS measurements and seismic waveform data , 2006 .

[9]  Hiromichi Tsuji,et al.  Silent fault slip following an interplate thrust earthquake at the Japan Trench , 1997, Nature.

[10]  P. Rosen,et al.  Atmospheric effects in interferometric synthetic aperture radar surface deformation and topographic maps , 1997 .

[11]  Analysis of Deformation Data at Parkfield, California: Detection of a Long-Term Strain Transient , 2000 .

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

[13]  Chen Ji,et al.  Slip history of the 2003 San Simeon earthquake constrained by combining 1‐Hz GPS, strong motion, and teleseismic data , 2004 .

[14]  D. Dreger,et al.  The Combined Inversion of Seismic and Geodetic Data for the Source Process of the 16 October 1999 Mw 7.1 Hector Mine, California, Earthquake , 2002 .

[15]  R. Bürgmann,et al.  Dynamics of Izmit Earthquake Postseismic Deformation and Loading of the Duzce Earthquake Hypocenter , 2002 .

[16]  Kerry E Sieh,et al.  Slip along the San Andreas fault associated with the great 1857 earthquake , 1984 .

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

[18]  Martin J. Siegert,et al.  EOS Trans. AGU , 2003 .

[19]  Kristine M. Larson,et al.  Frictional Properties on the San Andreas Fault near Parkfield, California, Inferred from Models of Afterslip following the 2004 Earthquake , 2006 .

[20]  P. Segall,et al.  Detection of a locked zone at depth on the Parkfield, California, segment of the San Andreas Fault , 1987 .

[21]  S. Titus,et al.  Thirty-Five-Year Creep Rates for the Creeping Segment of the San Andreas Fault and the Effects of the 2004 Parkfield Earthquake: Constraints from Alignment Arrays, Continuous Global Positioning System, and Creepmeters , 2006 .

[22]  Jessica R. Murray,et al.  Coseismic and initial postseismic deformation from the 2004 Parkfield, California, earthquake, observed by global positioning system, electronic distance meter, creepmeters, and borehole strainmeters , 2006 .

[23]  D. Schmidt.  Time-dependent land uplift and subsidence in the Santa Clara Valley , 2003 .

[24]  R. Bürgmann,et al.  Interactions between the Landers and Hector Mine, California, Earthquakes from Space Geodesy, Boundary Element Modeling, and Time-Dependent Friction , 2002 .

[25]  J. Langbein,et al.  Slip on the San Andreas Fault at Parkfield, California, over Two Earthquake Cycles, and the Implications for Seismic Hazard , 2006 .

[26]  P. Harsh,et al.  Slip on the San Andreas fault in central California from alinement array surveys , 1980 .

[27]  W Foxall,et al.  Clustering and Periodic Recurrence of Microearthquakes on the San Andreas Fault at Parkfield, California , 1995, Science.

[28]  Chen Ji,et al.  Preliminary Report on the 28 September 2004, M 6.0 Parkfield, California Earthquake , 2005 .

[29]  Andrew J. Michael,et al.  Three-Dimensional Compressional Wavespeed Model, Earthquake Relocations, and Focal Mechanisms for the Parkfield, California, Region , 2006 .

[30]  Robert M. Nadeau,et al.  Distribution of aseismic slip rate on the Hayward fault inferred from seismic and geodetic data , 2005 .

[31]  F. Amelung,et al.  Use of InSAR to identify land-surface displacements caused by aquifer-system compaction in the Paso Robles area, San Luis Obispo County, California, March to August 1997 , 2000 .

[32]  Chris Marone,et al.  On the mechanics of earthquake afterslip , 1991 .

[33]  J. C. Savage,et al.  Postseismic relaxation and transient creep , 2005 .

[34]  Yijun Du,et al.  How similar were the 1934 and 1966 Parkfield Earthquakes , 1993 .

[35]  William A. Bryant,et al.  Surface Fault Slip Associated with the 2004 Parkfield, California, Earthquake , 2004 .

[36]  Richard M. Goldstein,et al.  Rapid subsidence over oil fields measured by SAR interferometry , 1998 .

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

[38]  V. E. Levin,et al.  Rapid aseismic moment release following the 5 December, 1997 Kronotsky, Kamchatka, Earthquake , 2001 .

[39]  C. W. Chen,et al.  Two-dimensional phase unwrapping with use of statistical models for cost functions in nonlinear optimization. , 2001, Journal of the Optical Society of America. A, Optics, image science, and vision.