Geology topics

Research about Cook Inlet region

Source-linked reports with geographic coverage including Cook Inlet region.

3 recordsLinked to original sources

USGS2019

Ground-motion amplification in Cook Inlet region, Alaska from intermediate-depth earthquakes, including the 2018 MW=7.1 Anchorage earthquake

We measure pseudospectral and peak ground motions from 44 intermediate‐depth M w ≥ 4.9 "> M w ≥ 4.9 earthquakes in the Cook Inlet region of southern Alaska, including those from the 2018 M w "> M w 7.1 earthquake near Anchorage, to identify regional amplification features ( ⁠ 0.1 – 5    s "> 0.1 – 5 s period). Ground‐motion residuals are computed with respect to an empirical ground‐motion model for intraslab subduction earthquakes, and we compute bias, between‐, and within‐event terms through a linear mixed‐effects regression. Between‐event residuals are analyzed to assess the relative source characteristics of the Cook Inlet earthquakes and suggest a difference in the scaling of the source with depth, relative to global observations. The within‐event residuals are analyzed to investigate regional amplification, and various spatial patterns manifest, including correlations of amplification with depth of the Cook Inlet basin and varying amplifications east and west of the center of the basin. Three earthquake clusters are analyzed separately and indicate spatial amplification patterns that depend on source location and exhibit variations in the depth scaling of long‐period basin amplification. The observations inform future seismic hazard modeling efforts in the Cook Inlet region. More broadly, they suggest a greater complexity of basin and regional amplification than is currently used in seismic hazard analyses.

Alaska↗

USGS1980

Preliminary field geotechnical and geophysical logs from a drill hole in the Capps coal field, Cook Inlet region, Alaska

The drilling and logging activity described in this report was undertaken in August 1979, as part of the Energy Lands program of the U.S. Geological Survey. The general objectives of the project, of which this work is a part, are to provide an understanding of the nature, location, and extent of the engineering and environmental concerns in potential coal-development areas of the Cook Inlet region, Alaska. The geotechnical and geophysical logs presented in this report provide some of the basic physical-property and engineering data needed to evaluate geologic hazards, and to predict the response of geologic materials to large-scale coal mining and related development in the Capps coal field of the Beluga coal area. Specifically, the information may be used to help determine such things as natural- and cut-slope stability, spoil-pile stability, ground response to seismic activity, blasting effects, excavatability, bulking characteristics, ground-water conditions, and erosion potential.

Alaska↗

USGS1952

Pumice deposits in the Alaska Peninsula-Cook Inlet region

Three principal areas of pumice deposition have been found in the Alaska Peninsula-Cook Inlet region: Katmai National Monument, Augustine Island, and the Veniaminof-Aniakchak area. Vast quantities of pumice were deposited in Katmai National Monument resulting from the eruption of Mt. Katmai and related volcanic action in 1912. The principal deposits in the coastal areas of the Monument occur in the valley of the Katmai River and in the Amalik Bay-Kukak Bay area. Several areas of pumice deposition have been found on the south and west sides of Augustine Island, located 200 miles southwest of Anchorage. Mining was carried on by the Alaska Katmalite Corporation during the period 1946-1949, but no production has taken place since that time. Pumice deposits found in the Aniakchak-Veniaminof area have probably been derived from three principal sources: Aniakchak Crater, Mt. Veniaminof and Purple Crater. The limited data available indicate the deposits of chief interest occur in the valley of the Aniakchak River and in areas adjacent to Chignik Bay.

Alaska↗