UMass Geomechanics

Michele Cooke

230 Morrill Science Center
Department of Geosciences
University of Massachusetts
611 North Pleasant Street
Amherst, MA 01003-9297

email: cooke<at> <-- preferred
voice: 413-577-3142
video phone (ip): 128:119:45:50
video phone (direct dial up): 413-461-3286
video phone (interpreter relay) 413-461-3286
FAX: 413-545-1200

News from the Geomechanics research group

Alex Hatem defends her MS!

  • Alex Hatem successfully defended her MS thesis in August and will start a PhD at University of Southern California in Sept. Congratulations Alex!
  • When Alex isn't running analog expeirments with restraining bends she apparently wades in glacial lakes...
alex glacial

New review paper in Journal of Structural Geology

work min paper

Laura Fatarusso defends her MS!

laura and saf
  • Laura Fatarusso successfully defended her MS thesis in June. Congratulations Laura!!
  • In this silly photo Laura is showing us the northeast dip of the Coachella Valley segment of the San Andreas fault.

Justin Herbert defends his PhD!

  • Justin Herbert successfully defended his PhD thesis in May and will be headed to Chevron in July. Congratulations Justin!!
  • In this silly photo Mariel, Justin and Michele perform an interpretative dance of the uplift patterns within the San Bernardino Mountains. Yes, it is silly but if we cropped out Mariel and Michele, Justin would look even sillier!
  • BTW: Mariel and Justin had weddings within a week of eachother in June. Congratulations all around!
silly pic

Geomechanics Group presents at the 2014 Seismological Society of America meeting in Anchorage

New paper in Journal of Geophysical Research


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.

slip rates

New paper in Geology

strain distribution

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