A HAMMER AND A BETSY GUN: FIELD CAMP SUBSURFACE IMAGING IN THE WIND RIVER BASIN

The University of Missouri’s Branson Field Camp has run since 1911 in the Wind River Range near Lander, WY. Our 6-credit, 6-week course teaches a broad array of field methods in geology. During the sixth week of the course we offer advanced instructional projects in hydrogeology, geomorphology, structural analysis and geophysics. Our geophysics component was significantly expanded in 2006 when funds were obtained to buy a 32 channel seismic recording system for shallow geophysical surveys. In 2008 the geophysical curriculum was further expanded by including 72 additional channels from the IRIS-PASSCAL consortium’s equipment inventory. Since 2008, students have had been able to conduct research quality seismic surveys in and around the Wind River Mountain range in central Wyoming using 104 channel seismic data that allow for 12-24 fold reflection data to be collected. Students have worked on projects related to landfill expansion, Laramide fold-fault imaging, and active faulting adjacent to the Owl Creek Mountains. In addition to undergraduate students receiving training in geophysical data collection and processing, these seismic surveys have been significant components of seven Masters theses covering a wide range of topics.

During the 5^th week of camp students are introduced to the basic theory and applications of seismic imaging through a one-day project. This project includes a seismic refraction line that is used to measure the depth to the water table and bedrock in Red Creek Canyon. Students collect and analyze the data without the use of computational methods in a region where the subsurface has been relatively well mapped. During the 6^th week of the course, students work in advanced projects of their choice. Students who choose the Geophysical and Seismic Imaging track are introduced to advanced methods in seismic refraction and reflection imaging. These methods include time term inversion, refraction tomography, and Common Depth Point Stacking of seismic reflection data. There are two days of data acquisition and two days of processing where students have the chance to collect, process, and interpret the seismic data themselves. This work has produced seismic images of paleo-channels in the Wind River Formation, an active fault beneath the Owl Creek mountains, and numerous images of Laramide reverse faults.