Paper No. 3
Presentation Time: 2:15 PM
APPLICATION OF REMOTE SENSING TECHNIQUES TO DETERMINE THE KINEMATICS OF THE BULL LAKE CREEK LANDSLIDE, WIND RIVER MOUNTAINS, WYOMING
Understanding mass movements is key in reducing the cost of their remediation and overall impact on humans. This research aims to assess seasonal kinematics of the Bull Lake Creek Landslide (BLCS) in the Wind River Mountains of Wyoming. L-band interferometric synthetic aperture radar (InSAR) data were utilized to monitor short-term movement of BLCS and were correlated to meteorological and stream discharge data provided by USGS gauging and weather stations in the Bull Lake Creek Valley. Cumulative displacements recorded by InSAR were greater than 300cm over a 3 year time span, with maximum amounts of movement occurring during the months of May and June corresponding with peaks in stream discharge. For longer-term variations, a complete sequence of events from 1949 to present was pieced together for BLCS using a combination of aerial photos and satellite imagery, including much Landsat 5 data. Landsat 5 imagery provided a short repeat time and a long history of acquisitions, which allowed temporal constraints of events from 1984 to present. Results from the imagery analysis show massive cliff failure events (~5 million m³ of material) occur and that catastrophic mobilization of the slide occurs on decadal time scales associated with destruction and entrainment of mature growth trees (60cm dia.). The combined results show three periods of activity, (1) Catastrophic failure events associated with cliff retreat, (2) a decadal period of force re-equilibration defined by seasonal variations of small (centimeter to meter scale) movements, and (3) long term decadal or more periods of dormancy with little or no movement. Since other slides located in the Wind River Mountains share a similar structure as that of BLCS, it can be inferred that they may also fail catastrophically. Therefore, a re-assessment of the hazard that they pose to human infrastructure (such as Bull Lake Reservoir) may be in order.