JACKSON HOLE, Wyo. — Geologists of Jackson Hole will present Studies of Teton Fault seismicity–using lake sediment data Tuesday, April 5.
The series of glacially-excavated lakes positioned directly along the surface trace of the Teton fault at the base of the Teton Range are ideally situated to record fault activity since their formation approximately 15,000 years ago. Lakes in seismically active regions present valuable sedimentary archives of past seismic activity within their catchment.
The Teton fault is a major range-bounding normal fault that is recognized as one of the more active and hazardous faults in the Basin and Range Province, but which is also noted for its irregular postglacial paleoseismic history and relative quiescence during historical time.
Previous work has demonstrated that earthquake events are registered in Teton lake sediment sequences as distinct, basin‐wide turbidite deposits that can be identified visually in core section and through changes in sediment physical character. Importantly, the ages of these diagnostic deposits can be correlated between multiple lakes and to the timing of surface rupturing earthquakes identified in fault trench excavations.
Scientists have leveraged this well-constrained system to conduct a detailed study of prominent turbidites in Jenny Lake at high-resolution to develop a better understanding of the stratigraphic expression of past earthquakes in Teton lakes.
Jenny Lake is a relatively large (5 km2) and deep (75 meters max depth, 45 meters mean depth) glacially-carved basin located at the bottom of Cascade Canyon in the central Tetons, where postglacial slip rates are greatest.
Based on analyses, scientists created an interpretive model of turbidite formation and characterize sediment sources and transport pathways during past earthquake events. They further present emerging paleoseismic histories developed from four other nearby Teton lakes (Bradley, Taggart, Phelps, and Leigh lakes) to highlight similarities and differences between these independent records.
To learn more about the science and history behind the Teton fault, join Professor Darren Larsen of Occidental College as he presents Studies of Teton Fault seismicity –using lake sediment data Tuesday, April 5 at 6pm at St. John’s Episcopal Church. Or by Zoom.
