AEG Great Basin Chapter Meeting—October 18

AEG Great Basin Chapter MeetingOctober 18

Sign-up details below.

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.


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.

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

Scavenger Hunt in Carson City – plan your own trip!

Scavenger Hunt for Rocks Used to Build the Stewart Indian School

Authors: Jonathan G. Price, Elisabeth M. Price, and Dennis P. Bryan
Year: 2018
Series: Educational Series 62
Format: 6 pages, color
Free Download/view/purchase:

Plan your own trip! Explore a unique part of the cultural and geologic history of Carson City on this scavenger hunt at the Stewart Indian School.

The Stewart Indian School, which is located at 5500 Snyder Avenue in Carson City (south of town), was listed in the National Register of Historic Places as a Historic District in 1985. The site (approximately 110 acres) is managed by the State of Nevada.

The Stewart Indian School operated from 1890 to 1980. When Superintendent Frederic Snyder arrived in 1919, the wooden buildings were deteriorating. Under Snyder’s leadership and with the guidance of Hopi and Italian stonemasons, students learned the vocation of masonry and built over 60 buildings at the school, mostly from 1922 to 1942, using multi-colored rocks that were collected locally. Snyder also added landscaping with trees, flowers, and trellises. Stewart is one of few intact historical American Indian boarding-school campuses in existence in the United States.

The history behind this scavenger hunt fits perfectly with the 2018 Earth Science Week theme of “Earth as Inspiration.” The Hopi and Italian stonemasons created architectural masterpieces inspired by the beauty of the rocks quarried from local sites.

You can also visit other examples of Hopi masonry work in the Carson City area—such as the historic Wungnema House completed in 1948 and now managed by The Foundation for Carson City Parks and Recreation. This link above shows members of the Wungnema family cutting rock in nearby Brunswick Canyon which you can locate on NBMG Map 59.

NBMG Earth Science Week Field Trip 2018— Saturday, October 13—SIGN-UP NOW AVAILABLE!

Sparkling or Still? A Tour of the Geology from Soda Lakes to Stillwater Marsh, Nevada
Sign up here:

Governor Sandoval has proclaimed October 14-20, 2018 as Earth Science Week in Nevada, so we hope that you can join us on Saturday, October 13 as geoscientists from Nevada Bureau of Mines and Geology explain the geology of the Fallon area in celebration of Earth Science Week 2018 and the importance of earth sciences to the people of the state of Nevada.

Trip leaders will be Craig M. dePolo, Christopher D. Henry, James E. Faulds, Andrew V. Zuza, and Rachel E. Micander.

Major stops on this field trip will include the following:

  • Salt Wells geothermal power plant
  • Rainbow Mountain earthquake fault scarp
  • “Nevada Wonderstone” rockhounding locality
  • “Big Dig” flood mitigation project in Lahontan Valley
  • Rattlesnake Hill, a “young” (<1 million year old) volcanic cinder cone and lava flow complex overlooking Fallon
  • Soda Lake volcanoes (the youngest in Nevada!)

Participants will meet at the Gold Building in Reno at 8:00 AM and leave by 8:30 AM. The last stop will be Soda Lakes about 4:45 and then return to Reno.

For participants coming from Fallon or Fernley: Please meet at the Fox Peak Gas Station at 9:15 AM, 0.5 miles east of Maine Street on Highway 50, at N. Sherman St. Someone from NBMG will be at the gas station to give a short introduction and hand out guidebooks. We will depart from the Fox Peak Gas Station at 9:30 AM.

NBMG coordinates annual geology field trips for the public during, or near, Earth Science Week. These field trips are fun, educational, family oriented, and always free. NBMG has been an active participant in Earth Science Week since it began in 1998.

National Earth Science Week website:

Earth Science Week is October 14-20, 2018.

Focus Days:

Since October 1998, the American Geosciences Institute has organized this national and international event to help the public gain a better understanding and appreciation for the Earth sciences and to encourage stewardship of the Earth. This year’s Earth Science Week will be held from October 14-20, 2018 and will celebrate the theme “Earth as Inspiration.” The coming year’s event will emphasize artistic expression as a unique, powerful opportunity for geoscience education and understanding in the 21st century.