Jackson - Teton Fault
Images of trench cut in Antelope Flats to examine an antithetic fault (subsidiary), one that is part of the Teton Fault System. Photo: Courtesy of Glenn Thackray, ISU.

JACKSON, Wyo. — The Teton fault is located at the base of the Teton Range on the east side. It is a unique fault line for a variety of reasons—many of which continue to fascinate geologists.

For one, the fault is on the boundary of four major geologic provinces: the Basin and Range, Idaho-Wyoming Thrust belt, Rocky Mountain Foreland, and the Yellowstone volcanic plateau.

A 1994 journal paper called The Teton fault, Wyoming: Topographic signature, neotectonics, and mechanisms of deformation, identified the Teton fault as dipping or sloping to the east—an exception to the majority of major faults in the Basin and Range province, which dip to the west.

Images of trench cut in Antelope Flats to examine an antithetic fault (subsidiary), one that is part of the Teton Fault System. Photo: Courtesy of Glenn Thackray, ISU.

Aging the fault is somewhat controversial. A 1993 research paper The Teton fault, Wyoming: seismotectonics, Quaternary history, and earthquake hazards puts range somewhere between 2 and 13 million years old with a consensus that most of the movement on the fault occurred within the last 2 million years.

As far as seismicity, the earthquake hazard in the Teton-Yellowstone region is the highest in the intermountain west, according to journal research Seismicity and earthquake hazard analysis of the Teton-Yellowstone region, Wyoming (2009). Large earthquakes of magnitude 6.5 to 7.0 are estimated to occur in this region roughly every 200 years.

The Teton fault is an important feature in a larger region of seismic activity called the Intermountain Seismic Belt. This region extends from western Montana south to northern Arizona.

Knowledge of the Teton fault has been expanded in the past five years under robust efforts to learn more the fault and its earthquake history and its impact on the Teton-Jackson Hole landscape.

Fault trenching projects at five locations along the fault, from Steamboat Mountain to Ski Lake, have greatly expanded what scientists know about the most recent two or three earthquake events, spanning the last 10,000 years of regional geologic history.

New ages of faulted glacial landforms at the mouths of major Teton valleys reveal longer-term fault movements, and sediment cores from lakes mantling the front of the range have revealed the timing of sediment pulses and the long-term patterns of erosion in the Tetons. Together, these efforts reveal much new information, and also reveal how much remains to be learned.

Catch up with everything Teton fault during a Geologists of Jackson Hole Zoom presentation of Artisan fault trenching and the recent history of the Teton fault by Glenn Thackray, Idaho State University.

Join the Zoom meeting Tuesday, May 19 at 6 p.m. by clicking on the link below. Or join manually using the meeting number and password. How to Zoom better manual.

Meeting ID: 828 9008 8818
Password: 614264

If a computer isn’t available you can phone in by calling: (253) 215-8782