An analysis of the known geologic factors in the Point Whitshed-Cape Yakataga area, Alaska, indicates that the most suitable location for a harbor to be excavated by nuclear-device techniques is a section of coastline from Point Martin to the town of Katalla.
Three sites selected in the Point Martin-Katalla area are indicated on plates 5 and 9. Site 1 at Point Martin is underlain by terrace gravel overlying sedimentary rocks of Tertiary age. The site is protected from south- east storms but not from southwest storms. Longshore transport of sediments is to the west during high tides and either lacking or to the east during low tides. The 60-foot offshore contour is within 1.5 miles of the site and the 30-foot offshore contour is within 0.4 mile.
Site 2 at Palm Point is underlain by beach gravel, terrace gravel, and muskeg deposits that overlie Tertiary sedimentary rocks. The site is protected from southwest storms but exposed to southeast storms, which are the major ones in the Point Whitshed-Cape Yakataga area. The beach at this site is being eroded actively and the sediments are carried offshore by waves that break at right angles to the beach. The 60-foot offshore contour lies within 2 miles of the site area; the 30-foot offshore contour is within 0.3 miles.
Site 3 at the town of Katalla is underlain by beach and terrace deposits overlying Tertiary sedimentary rocks. This site offers better protection than either of the other two from southeast and southwest storms. Longshore transport along a spit east of the site has filled the Katalla River to within 3 feet of the surface to mean low tide. Dredging requirements at this site would be much greater than at sites 1 and 2. The 60-foot offshore contour is within 3.5 miles of Katalla and the 50-foot contour within 1 mile.
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Engineering geology bearing on harbor site selection along the Gulf of Alaska from Point Whitshed to Cape Yakataga, Alaska