EAGER: Reconstructing the Seismic History of the Teton Fault Using Lake Sediments at Grand Teton National Park, WY

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

Abstract A non-technical description of the project, which explains the project's significance and importance The spectacular scenery of Grand Teton National Park is largely the result of movement along the Teton Fault, which is still active today. Numerous lake basins populate the mountain front and earthquakes resulting from fault movement produce landslides that accumulate distinctive sediment layers on the lake floor. This project will investigate these sediments in order to determine the characteristics of the layers resulting from fault movement and to calculate the recurrence interval of earthquakes in the Grand Teton region over the past 15,000 years. In addition to developing methods for the long-standing problem of identifying the tectonic influences upon sediment deposition, this research will help Grand Teton National Park evaluate earthquake hazards and provide the basis for an educational program for park visitors. A technical description of the project This EAGER project will employ a comprehensive suite of well-established methods to investigate this distinctive geologic setting, where past tectonic activity is unusually well preserved in lake sediments. Multi-beam sonar bathymetric mapping, seismic surveys, and sediment cores from multiple lakes located directly on the Teton fault will be evaluated to produce: i) a high-resolution (centimeter-scale) bathymetric map of lake-floor morphology; ii) an inventory of landslide deposits and slope failures preserved in multiple basins positioned along the Teton fault trace; and iii) a continuous and accurately dated 15,000-year-long record of earthquakes and earthquake-driven disturbances at Grand Teton National Park. The paleoseismic record generated through this research is a key initial step toward developing a solid understanding of interactions among tectonic, climatic, and geomorphic processes, including their relative roles in driving landscape evolution. The results will also contribute to the development of a promising method for constructing paleoseismic records from lake sediments.