Airborne Light Detection and Ranging (LiDAR) on Turtle Mountain

What is LiDAR?

Airborne LiDAR sensors are becoming an increasingly common and cost-effective tool projects requiring characterization of relatively large areas and landslide hazard assessment.

Airborne LiDAR systems have a laser mounted beneath an airplane or helicopter that follows a predefined path. The laser scans the ground by emitting tens of thousands of pulses per second. To get measurements for the horizontal coordinates (x, y) and elevation (z) of the objects scanned, the aircraft position is determined with GPS measurements and the distance from the aircraft to the ground.

As this technology has such a dense coverage and can distinguish between ground surface, trees and buildings, we can use it to create a high-resolution model of the bare-ground surface, without vegetation. For scientists and engineers in the field of geological hazards, this provides a valuable new tool for mapping and characterizing ground-movement hazards.

Shaded-relief maps for two grids generated from unfiltered (left) and filtered data (right), respectively. You can easily identify mine subsidence on the filtered map.

Using LiDAR on Turtle Mountain

In 2006, Alberta Geological Survey purchased the license for LiDAR data for a 33 km² area covering Turtle Mountain and Frank Slide. We created a high-resolution, digital elevation model (DEM) from the data provided by the LiDAR 3D point cloud. Using Geographic Information System (GIS) tools, we created a 3D model of the mountain to assess unstable areas and to create detailed, structural maps to verify landslide mechanisms and potentially unstable volumes. These data have been critical in revising interpretations of Turtle Mountain's instabilities and led to expanding our monitoring network on the mountain.

Results

Recent and ongoing studies have used LiDAR data to make new interpretations about the unstable portions of Turtle Mountain. Alberta Geological Survey staff and collaborators have published recent articles on this topic.

Click on images to enlarge.