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TitleStructure and kinematics of the Eastern Denali fault from drone and crewed airborne lidar surveys
AuthorFinley, T; Salomon, G; Stephen, R; Nissen, E; Cassidy, J FORCID logo; Menounos, B
SourceSeismological Society of America, Proceedings vol. 93, no. 28, 2022 p. 1298-1299
Alt SeriesNatural Resources Canada, Contribution Series 20210549
PublisherSeismological Society of America
MeetingSeismological Society of America Technical Sessions; Bellevue; US; April 19-23, 2022
Mediapaper; on-line; digital
File formatpdf
SubjectsScience and Technology; Eastern Denali Fault
ProgramPublic Safety Geoscience Assessing Earthquake Geohazards
Released2022 04 01
AbstractThe Eastern Denali fault (EDF) in the Yukon has not, until now, been widely covered by lidar data, and interpretations of its kinematics and paleoseismic record have consequently been subject to uncertainty. We present new lidar data collected with a rotary-wing drone over several segments of the EDF on the southwest side of Kluane Lake, which enabled the production of Digital Terrain Models (DTMs) with ~30 cm spatial resolution. We also present new lidar data collected with a crewed fixed-wing aircraft between the Slims and Duke rivers. These datasets offer a considerable increase in spatial resolution and canopy penetration compared to existing spaceborne and airborne photogrammetric Digital Surface Models (DSMs) of the EDF. We re-map the EDF in detail and find several locations where previous DSMs did not accurately portray the fault surface trace. The lidar data also provide improved estimates of fault offset and kinematics: stream channels and hill slopes that cross the fault at high angles indicate dextral offsets of 5-75 m. Vertical separation ranges from 0-20 m, varying between NE- and SW-side up. Offset across the fault varies considerably between geomorphological surfaces of different ages (i.e., glacial drift vs. younger fluvial terraces), suggesting that the lidar data may be able to distinguish multiple slip events. The higher spatial resolution achieved by the drone lidar reveals possible E-W-trending compressional structures (fault tips or fold axes) on a series of sediment mounds along the fault. These short-wavelength features are not visible in the crewed airborne lidar. Drone lidar is a relatively new technology, and this study allows for a comparison of the costs and benefits of drone versus crewed airborne lidar acquisition for active tectonics research; the drone is less expensive to deploy and offers a substantial increase in point density, but covers a smaller area and is subject to several practical and regulatory constraints. (Invited Contribution)
Summary(Plain Language Summary, not published)
New lidar data sets are analysed to provide new constraints on the tectonics and movement along the Eastern Denali fault zone in the Yukon. We find evidence for substantial movement along this fault zone, and preliminary indications that these new data can distinguish multiple slip events. This new information will improve assessments of earthquake hazards in the Yukon. As one of the first detailed studies using a relatively new technology (Drone lidar), this study allows for a comparison of the costs and benefits of drone versus crewed airborne lidar acquisition for active tectonics research.

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