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Helicopter and field reconnaissance surveys to assess seismic hazards along the Alaska Highway corridor between Tetlin Junction and the Yukon (Canada) border were conducted by the Alaska Division of Geological & Geophysical Surveys. Faults previously identified as having "suggestive or suspicious" evidence of Quaternary deformation were evaluated, including the Dennison Fork, Caribou Creek, Midway Lake, Northway Junction, and Airs Hills faults, and the Tetlin Lake and Ladue River lineaments. The results indicate that all of the faults are characterized by mature to absent geomorphic expression, lack features indicative of Holocene and/or Quaternary deformation, and should not be considered active faults in future...
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The Dot "T" Johnson and Cathedral Rapids faults represent the eastern part of the Northern Foothills fold and thrust belt, and are geomorphically well expressed by triangular facets, anticlinal warps, and scarps in Quaternary deposits between Granite Mountain and Tok River. Previous paleoseismic trenching indicates that these faults have both generated at least one and possibly multiple Holocene earthquakes. We created various LiDAR-derived base maps along the Dot "T" Johnson fault to assess the relative utility of each product in assessing the location of tectonic features. Our results indicate that the most robust interpretations require combined observations from multiple products including hillshade, slope,...
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