Geology topics

Research about Homer, Alaska

Source-linked reports with geographic coverage including Homer, Alaska.

3 recordsLinked to original sources

USGS1966

Effects of the earthquake of March 27, 1964, in the Homer area, Alaska

The March 27, 1964, earthquake shook the Homer area for about 3 minutes. Land effects consisted of a 2- to 6-foot subsidence of the mainland and Homer Spit, one earthflow at the mouth of a canyon, several landslides on the Homer escarpment and along the sea bluffs, and minor fissuring of the ground, principally at the edges of bluffs and on Homer Spit. Hydrologic effects consisted of at least one and possibly two submarine landslides at the end of the spit, seiche waves in Kachemak Bay, ice breakage on Beluga Lake, sanding of wells, and a temporary loss of water in some wells. Seismic damage to the community was light in comparison with that of other communities closer to the epicenter. One submarine landslide, however, took out most of the harbor breakwater. The greatest damage was due to the subsidence of the spit, both tectonically (2–3 ft) and by differential compaction or lateral spreading (an additional 1–4 ft). Higher tides now flood much of the spit. The harbor and dock had to be replaced, and buildings on the end of the spit had to be elevated. Protection works for other buildings and the highway were needed. These works included application of fill to raise the highway and parts of the spit above high tides. Reconstruction costs and disaster loans totaled about $2½ million, but this amount includes added improvement costs over preexisting values. Homer Spit in particular and the Homer area in general rank as areas where precautions must be taken in selecting building sites. The hazards of landslides, earthflows, compaction and submarine slumping—all of which might be triggered by an earthquake—should be considered in site selection. In plan, Homer Spit resembles a scimitar with its curving blade pointed seaward. It is about 4 miles long and as much as 1,500 feet wide. The spit is composed largely of gravel intermixed with some sand. After the earthquake and the resulting tectonic subsidence and compaction, much of the spit was below high-tide levels and consequently flooded periodically. The entire beach face has retreated. Much of the material eroded from the beach has been redeposited to form a new storm or frontal berm, locally migrating around buildings and covering roads. Beach recession of 10–15 feet is probably the overall average; maximum recession 1 year after the earthquake was 56 feet along one limited section of the distal end of the spit. Subsidence of the mainland has caused accelerated erosion of the beaches and headlands that have been—and are—source areas for the material deposited on Homer Spit. The resulting increased supply of gravel and sand probably will cause the spit to widen gradually on the Cook Inlet side. Similarly, the new frontal berm will probably grow to a height sufficient to prevent overtopping by all but the larger storm swashes. The nature of shore processes on the spit has not been materially altered by subsidence, but the rates of erosion and deposition have been accelerated. The lasting effect of subsidence (excluding flooding) will be enlargement of the beach on the Cook Inlet side and gradual wasting of the beach on the bay side of the spit.

Alaska↗

USGS1952

Coal investigations in the Homer district, Kenai coal field, Alaska, in 1950 and 1951

This report presents the results of work done in the last three weeks of the 1950 field season and in all of the 1951 season, and supplements reports by Barnes (19149) and Cobb (1950, 1951). Barnes' report covers investigations of coal-bearing rocks of the Tertiary Kenai formation in a coastal belt between Bluff Point and the head of Kachemak Bay (pl. 2). Cobb's reports deal with similar rocks exposed along the coast between Bluff Point and the beach bluffs about 7 miles south of the village of Cohoe, and in the lower reaches of the Ninilchik River valley. The present report covers extensions of previous mapping in the valleys of Deep Creek and the Anchor River, and on high land between the area covered by Barnes' report and the Anchor River valley. The results of ground and aerial reconnaissance of most of the Homer district also are presented. The writer, assisted by F. J. Markewioz, carried on the field work which is the basis for this report, between August 13 mad September 6, 1950, and between May 10 and August 30, 1951. Field work included traverses along Deep Creek and the Anchor River, and between the southeast end of Tustumena Lake and the head of Kachemak Bay. It included also the detailed measurement and tracing of coal beds on the upland north and northwest of Homer, sampling of coal beds along the northwest shore of Kachemak Bay and the southeast shore of Cook Inlet, and both ground and aerial reconnaissance of the rest of the Homer district and adjoining areas. The writer is indebted to James W. Scott, Forester, U. S. Bureau of Land Management, Lomer, Alaska, who accompanied him on a traverse from Tustumena Lake to Kaohemak Bay and assisted at many other times during the 1950 and 1951 field seasons. Ralph Gaetano and Thomas Shelford of Homer were of great assistance in locating and reaching isolated outcrops of coal-bearing rooks. Daniel B. Krinsley, of the Alaska Terrain and Permafrost Section of the U. S. Geological Survey, has generously made available the results of many of his observations in remote parts of the Homer district which could not be visited by the writer.

Alaska↗

USGS1949

Coal investigations on the southern margin of the Homer district, Kenai coal field, Alaska, in 1947-48

The presence of coal in the Tertiary Kenai formation of western Kenai Peninsula has been known since 1880, chiefly as exposed along the north shore of Kachemak Bay and the adjoining east shore of Cook Inlet (fig. 1). Several early attempts were made to develop a commercial mine in this area in the period 1888-1902 but none progressed beyond the prospecting stage and little coal was produced. In 1915 the mining of coal-was started at the Bluff Point mine, 1 1/2 miles west of Homer. Available records indicate that this mine produced between 20,000 and 25,000 tons of coal before closing in 1324. No further attempt at mining was made until 1946, when the Homer Coal Corporation began development near the site of the old Bluff Point mine. Development work during 1946 and 1947 included construction of a truck-loading bunker, mess hail, bunkhouse, and an incline end hoist for raising coal from the tunnel in the face of the beach bluff. Only a small amount of underground work was done in 1946 and 1947, and practically none in 1948. A preliminary step toward more extended investigation of the coal deposits of the Homer district was made by the writer, accompanied by T. J. Jolley of the U. S. Bureau of Mines, in the summer of 1946. Several days were spent in examining the principal coal exposures near Homer and collecting samples to determine the desirability of more detailed investigation. Detailed examination of the coal deposits of the Homer district was started by the Geological Survey in 1947. The period July 17 to September 14 was spent by the writer, assisted by H. C. Wagner, geologist, and L. A. Hale, field assistant, in reconnaissance of isolated coal exposures in an area extending several miles north of Homer, and in measuring detailed stratigraphic sections in the bluffs just north of Homer between Coal (Bidarki) and Fritz Creeks.

Alaska↗