Denali Fault - 2024 - Airborne LiDAR Survey

The Denali fault arcs through central Alaska and across southwestern Yukon. In 2002, the Alaskan segment broke in a M7.9 earthquake, generating a 340 km-long rupture that stopped 130 km short of the Yukon border. East of the border, a 240 km-long linear scarp hints at large, prehistoric ruptures along the Yukon segment, but the dates, frequencies and magnitudes of those past events are unknown.

To address this knowledge gap, we used an aircraft-mounted laser sensor ("LiDAR") to create a high-resolution topographic map from which the fault surface rupture can be mapped and measured. LiDAR data have been collected along the Alaskan section of the Denali fault, but the Yukon portion is conspicuously lacking. The new lidar data will illuminate landforms offset by the fault, which we will measure and ultimately date (e.g. with radiocarbon) to determine the rate and magnitude of past earthquakes. A better record of past events may tell us why the Yukon segment did not rupture in 2002, and on what time frame and with what magnitude it may rupture again.

Results will form key inputs into Canada's seismic hazard models and building codes, which aim to ensure that infrastructure (buildings, roads, dams, etc.) can withstand the expected ground accelerations. Results will be especially important for assessing seismic risks to several natural resource projects in the area, including a proposed battery-metal mine and a geothermal energy project. They will also contribute to an ongoing debate as to whether faults host repeated earthquakes on the same segments, or whether rupture patterns are random. It is vital to collect data from analogous onshore faults, like the Denali Fault, to determine whether pre-historic rupture patterns are at all indicative of future ones.

Due to a combination of shipping delays on Hakai’s new LiDAR system, and scheduling issues/opportunities, Hakai contracted Kisik Geospatial Surveys to collect LiDAR of the Denali Fault. Imagery was collected but subsequently lost, and it is unavailable until relocated.