![]() ![]() Top lidar image is looking east at Yankee Jim Canyon along highway 89 showing numerous large prehistoric landslides (shown by colored arrows). Lidar imagery is given as a colored, shaded slope map, with higher elevations in brown and white, and lower elevations in green. Shaded relief maps based on lidar data and showing landslides in the area of Yankee Jim Canyon, Montana. The 1959 M 7.3 Hegben Lake event was the largest historical earthquake in the Intermountain West region, and it caused one of the largest seismically triggered landslides at Earthquake Lake, created extensive fault scarps, and altered geyser and hot spring activity through the park. Although Yellowstone is more well known for its past volcanic eruptions and active hydrothermal systems, large damaging earthquakes and landslides have occurred in the region. Yet the many people that make the scenic drive to Gardiner at the northern park entrance may not realize the surrounding landscape has a rich record of prehistoric earthquakes that ruptured the ground surface, and numerous landslides of “gigantic” proportions. ![]() Paradise Valley and gateway communities north of Yellowstone National Park not only have experienced rapid growth in population but also in annual visitors (over 4 million visitors a year). The laser pulses that penetrate the vegetation have the longest travel times and thus are the last to return, and these are combined with GPS airborne and ground controls to generate a point cloud dataset that is used to build a high-resolution bare-earth digital elevation model (DEM) or digital terrain model (DTM). The lidar sensor rapidly emits laser pulses (>100,000 per second) that are reflected back from the ground surface or any object along their paths. Lidar stands for Light Detection and Ranging and uses a sensor commonly mounted on an airplane for large surveys. In 2022, a new lidar dataset for Park County, Montana, was released to the public. Recent advances in high resolution topographic datasets that use lidar have enabled geologists and earth scientists to virtually “remove” vegetation and reveal the bare earth ground surface-including, for example, active faults on the fringes of Yellowstone National Park. Geological surface mapping has traditionally used aerial photos and direct observations through fieldwork, but the land surface is often obscured by vegetation. (Lidar visualization by Yann Gavillot, MBMG, using 3-D scene in ArcGis Pro). Subtle flutes and ridges extending horizontally across the hillslopes above the scarps were carved by glacial ice flowing down the Emigrant Valley from the Yellowstone ice cap. Bottom image is a southeastward view showing the same fault scarp. Highway 89 is visible on the left side of the image as a pair of parallel lines. The right side of the image shows an oblique perspective of the Emigrant fault scarp (shown by red arrows) that vertically offset young alluvial fan deposits. Top image is a northwestward view (toward Livingston) of Paradise Valley near Carbella. Shaded relief maps based on lidar data and showing fault scarps in Paradise Valley, Montana.
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