Comparison of Remote Sensing Imagery for Geologic Studies

SMSU Event Center BC

This study compared multiple types of remotely sensed imagery, obtained in the Badger Hill area adjacent to the CSUSB campus, to determine the most useful method in studying a particular geologic feature. Conventionally-obtained historical aerial photographs are the most widely available images, but the availability of inexpensive Unmanned Aerials Vehicles (UAVs) opens new sources of photography. LiDAR imagery can be used in areas where the ground surface and topography are hidden by dense vegetation. Geologic features in the Badger Hill area include fault scarps, landslide scarps, erosion, and offset streambeds. The LiDAR imagery was the most beneficial when analyzing erosion rill development or alluvial streams where sedimentary bars or channel banks have been altered by fluvial processes. Most of the geological features show greater detail in LiDAR images than in the historical photographs or satellite images. Conversely, landslide scarps do not show up on the LiDAR as well as they do in the Google Earth satellite images; the tilting and zooming on the 3D Google Imagery is a revealing tool. Similar imagery was obtained with a UAV flying at low elevations where helicopters and planes are not able to, and with repeated coverage. UAVs can also obtain specific viewpoints at different angles and under variable lighting conditions. The comparison of the remote sensing imagery shows that each method has its benefits for a specific feature depending on what is needed for the site investigation.