Paleoseismic and Lidar Investigations Along the Cathedral Rapids and Dot "T" Johnson Faults, Interior Alaska
Dates
Year
2013
Citation
Koehler, Rich D., and Farrell Woods, Rebecca-Ellen, 2013, Paleoseismic and Lidar Investigations Along the Cathedral Rapids and Dot "T" Johnson Faults, Interior Alaska: Alaska Division of Geological & Geophysical Surveys: Fairbanks, Alaska, v. Report of Investigation 2013-4, p. 21-21.
Summary
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, intensity, and aspect [...]
Summary
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, intensity, and aspect maps. Interpretation of a new paleoseismic trench excavated across the Cathedral Rapids fault places a constraint on the timing of a folding event to after around 850 cal yr BP. On the basis of folded deposits and unconformable stratigraphic relations, we infer the existence of an active blind thrust splay of the Cathedral Rapids fault beneath the scarp. ABSTRACT FROM AUTHOR]; Copyright of Report of Investigation is the property of Alaska Division of Geological & Geophysical Surveys and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
