SEMINAR: REMINDER: GEOTOPICS Today: Dr. Wesnousky (2/14 3:15 pm)

[Qiong Zhang <qzhang@rsmas.miami.edu>]

##### G  E  O  T  O  P  I  C  S  #####

    P  r  e  s  e  n  t  s

3:15 PM, Monday,  February 14th, 2011

   SLAB Seminar Room, S/A 103

Refreshments 3:00 PM

Steven Wesnousky

    Professor, University of Nevada, Reno

 "The Walker Lane and Basin and Range Fault Systems of Western North America: Styles and Rates of Deformation, Fault Mechanics, and Insights to the Structural Evolution of a Major Transform Plate Boundary"

            The Great Basin physiographic province of the western United States encompasses an area reaching ~800 km in width between the Sierra Nevada to the west and the Wasatch Mountains to the east. Within reside the Walker Lane and Basin and Range fault systems, which together accommodate upwards of 20-25% of the total 5 cm/yr of ongoing Pacific-North American transform plate motion. The Walker Lane is manifest as an approximately 50 km zone of disrupted topography and discontinuous, northwest-trending, strike-slip and normal faults along the eastern flank of the Sierra Nevada. The Basin and Range extends eastward from there and is marked by relatively regularly-spaced, north-northeasterly striking normal faults. The Center for Neotectonic Studies at the University of Nevada-Reno has been conducting Quaternary mapping and paleoseismic trenching studies of active faults across the region to elucidate the sense, rate, style and pattern of fault deformation and the recurrence characteristics of earthquakes that occurred during the Late Pleistocene. In this talk I combine these observations with published geodetic measurements of ongoing elastic strain accumulation and geological documentation of longer-term, cumulative fault offsets. These studies address the relationship of strain accumulation to strain release over different time scales and put forth the idea that the Walker Lane fault system is analogous to an earlier stage in the structural development of the San Andreas--when the system was transtensional and before sufficient slip accumulated to yield the now throughgoing, San Andreas fault.

-- 
Qiong Zhang

Marine Geology and Geophysics
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami Fl 33149