AEG Great Basin Chapter Meeting—October 18
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Speaker: Rich Koehler, NBMG
Topic: Active Faulting in the North Valleys Region of Reno, Nevada: A Distributed Zone within the Northern Walker Lane
Abstract: At the latitude of Reno, Nevada, USA, ~15-25% of the Pacific/North American plate boundary strain is accommodated east of the Sierra Nevada through a combination of normal oblique (dextral) slip along the eastern Sierra Nevada range front and dextral slip along faults in the northern Walker Lane. The North Valleys region sits within the northern Walker Lane directly east of the Sierra range front and is characterized by a series of small north-striking basins bound by Quaternary active faults that accommodate dextral oblique extension. Geodetic studies of the North Valleys estimate that the faults collectively accommodate 0.9-1.7 mm/y of extension and <0.3 mm/y of dextral slip; however, few Quaternary geologic/paleoseismic studies have been conducted.
Here I summarize geologic observations on the tectonic geomorphic expression and relative activity of faults within and bounding the North Valleys based on interpretation of lidar-derived hillshade images and field reconnaissance. The results indicate that the faults all exhibit evidence of active late Quaternary deformation, including offset alluvial fan deposits and abrupt range-front escarpments and are characterized by extension rates on the order of hundredths to tenths of millimeters per year. Cumulative geologic extension rate estimates across the North Valleys are slightly less than rates measured geodetically. On-going mapping, paleoseismic trenching and numerical dating of displaced surfaces are being conducted to refine the style and amount of deformation with the goal of better understanding the role of the North Valleys in transferring dextral oblique extension from the Sierra Nevada range front to faults along the northeastern Walker Lane.
Biography: Dr. Rich D. Koehler is an Assistant Professor at the Nevada Bureau of Mines and Geology and the Department of Geological Sciences and Engineering at the University of Nevada, Reno. His research is focused on earthquake geology, Quaternary geology, paleoseismology, geomorphology, and engineering geology. Dr. Koehler is specialized in using advanced techniques including air photo, lidar, and satellite imagery interpretation, Quaternary geologic and geomorphic mapping, and surveying to assess geohazards in a wide variety of terrains. Dr. Koehler is particularly well versed on topics in Quaternary geology in Nevada and has mapped in numerous valleys throughout the state.
His paleoseismic research throughout the western U.S.—including the study of faults in California, New Mexico, Washington, Alaska, and Nevada—has been funded by the U.S. Geological Survey and the National Science Foundation. His international project experience includes studies in Turkey, Taiwan, Jamaica, and Haiti.
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1981 TERMINAL WAY
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SOCIAL HOUR: 5:30PM (Sponsored by Doug and Merrily Graham)
Members: $27.00, Non-Members: $30.00, Students: $20.00
The Bar is sponsored, and we are providing complementary dinners to the first three students who submit RSVP’s. Any additional students will be charged $20.
RSVP NO LATER THAN 5PM, TUESDAY, OCTOBER 16TH TO MERRILY GRAHAM:
Merrily Graham, AEG Great Basin Chapter Chairperson
Please give us a 48 Hour Cancellation Notice if you are not able to attend. “No shows” without proper notification will be charged. Thank you.
AEG Meeting Schedule—Fall 2018 / Spring 2019
October 18, 2018 – Rich Koehler, Active Faulting in the North Valleys Region of Reno, Nevada
November 8, 2018 – Gary Luce, “Burning Man Black Rock Playa Investigation”
December 13, 2018 – Meet & Greet Holiday Party & Fund Raiser
January 10, 2019 – Shawn Gooch, “Permitting Metals Mining in Nevada”
February 7, 2019 – Jahns Lecturer, Debbie Green, AEG Dinner Presentation
February 8, 2019 – Jahns Lecturer, Debbie Green, “Tale of Two Waste Sites” lecture on the UNR campus
March 14, 2019 – Wendy Calvin, “Core Spectral Imaging”
April 18, 2019 – Student Night