sunset_kauai (c) Bridget Smith-Konter

GNSS and InSAR Applications - Pacific-North American Plate Boundary

Space geodetic techniques, such as GPS/GNSS and InSAR, provide valuable data that offer a detailed synoptic picture of the strain accumulation along Earth's plate boundaries. Working with colleagues at UCSD/SIO, we utilize a methodology to integrate multiple years of Sentinel-1 InSAR and continuous GNSS time series to achieve 6 to 12-day sampling of surface displacements at ~500 m spatial resolution over the entire San Andreas fault system (SAFS) [i.e., Xu et al., 2021].


One of the largest uncertainties of earthquake hazard models is the amount of plate boundary deformation that is accommodated by off-fault strain. Achieving an ideal 50-nanostrain/yr accuracy at a 10-km resolution (i.e., a typical fault locking depth) requires a 2-D horizontal velocity model that has an accuracy of 0.5 mm/yr. Currently GNSS provides this accuracy but not at 10-km spatial resolution; InSAR provides this spatial resolution but cannot achieve this accuracy. Moreover, this objective requires all three components of deformation, integrated GNSS, InSAR, and high-accuracy modeling, to provide both high spatial and high temporal resolution at the plate boundary.

SAF Strain Rate

Related Publications:

  • Ward, L., B. Smith-Konter, X. Xu, X. Tong, and D.T. Sandwell (2021), Seismic moment dependence on crustal rigidity for the southern San Andreas Fault System, Journal of Geophysical Research, https://doi. org/10.1029/2020JB021208.
  • Xu, X., L. Ward, J. Jiang, B. Smith-Konter, E. Tymofyeyeva, E. O. Lindsey, A. G. Sylvester and D.T. Sandwell (2018), Surface creep rate of the Southern San Andreas Fault modulated by stress perturbations from nearby large events, Geophys. Res. Lett., doi: 10.1029/2018GL080137.
  • Tong,X., B. Smith-Konter, and D.T. Sandwell, Is there a discrepancy between geological and geodetic slip rates along the San Andreas Fault System? (2014), J. Geophys. Res., doi:10.1029/2013JB010765.
  • Howell, S., B. Smith-Konter, N. Frazer, X. Tong, and D.T. Sandwell (2016), The vertical fingerprint of earthquake-cycle loading in Southern California, Nature Geosciences, doi: 10.1093/2015-03-04591.
  • Tong, X., D.T. Sandwell, and B. Smith-Konter (2013), High-resolution interseismic velocity data along the San Andreas Fault System, J. Geophys. Res., 118, doi:10.1029/2012JB009442.
  • Smith-Konter, B., D. Sandwell, and P. Shearer (2011), Locking depths estimated from geodesy and seismology along the San Andreas Fault System: Implications for seismic moment release, J. Geophys. Res., 116, B06401, doi:10.1029/2010JB008117.
  • Smith-Konter, B., D. Sandwell, and M. Wei (2010), Integrating GPS and InSAR to resolve stressing rates of the SAF System, EarthScope inSights Newsletter, Summer 2010.
  • Wei, M., D. Sandwell, and Smith-Konter, B., Optimal combination of InSAR and GPS for measuring interseismic crustal deformation, J. Adv. in Space Res., doi: 10.1016/j.asr.2010.03.013, 2010.
  • Wdowinski, S., B. Smith-Konter, Y. Bock, and D.T. Sandwell (2007), Diffuse interseismic deformation across the Pacific-North America plate boundary, Geology, doi:10.1130/G2938A.1.