Justin Herbert defends his PhD!
230 Morrill Science Center
Department of Geosciences
University of Massachusetts
611 North Pleasant Street
Amherst, MA 01003-9297
email: cooke<at>geo.umass.edu <-- preferred
video phone (ip): 128:119:45:50
video phone (direct dial up): 413-461-3286
video phone (interpreter relay) 413-461-3286
Justin compares results of models that simulate block-like network faults with results of a more discontinuous network that more closely follows the mapped active fault traces. While the strike-slip rates along the fault networks differs (figure at right), the interseismic deformation is not significantly distinct (figure above). This suggests that inferring slip rates from GPS velcoities with an overconnected fault network will produce erroneously fast slip rates and could account for part of the discrepancy in slip rates between geologic and geodetic estimates.
Herbert, J. W., M. L. Cooke, and S. T. Marshall (2014), Influence of fault connectivity on slip rates in southern California: Potential impact on discrepancies between geodetic derived and geologic slip rates, J. Geophys. Res. Solid Earth, 119, doi:10.1002/2013JB010472.
Justin shows that 40% of the strain within the Eastern California Shear Zone may be accomodated as permanent deformation between the faults rather than as slip along the faults. This could explain why geodetic studies that assume no off-fault deformation get faster fault slip rates than geologic investigations.
Herbert, Justin W., Michele L. Cooke, Michael Oskin and Ohilda Difo, 2014. How much can off-fault deformation contribute to the slip rate discrepancy within the Eastern California Shear Zone?, Geology. doi:10.1130/G34738.1