Potential seismic hazards and tectonics of the upper Cook Inlet basin, Alaska, based on analysis of Pliocene and younger deformation
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Abstract
The Cook Inlet basin is a northeast-trending forearc basin above the Aleutian subduction zone in southern Alaska. Folds in Cook Inlet are complex, discontinuous structures with variable shape and vergence that probably developed by right-transpressional deformation on oblique-slip faults extending downward into Mesozoic basement beneath the Tertiary basin. The most recent episode of deformation may have began as early as late Miocene time, but most of the deformation occurred after deposition of much of the Pliocene Sterling Formation. Deformation continued into Quaternary time, and many structures are probably still active. One structure, the Castle Mountain fault, has Holocene fault scarps, an adjacent anticline with flower structure, and historical seismicity. If other structures in Cook Inlet are active, blind faults coring fault-propagation folds may generate Mw 6–7+ earthquakes. Dextral transpression of Cook Inlet appears to have been driven by coupling between the North American and Pacific plates along the Alaska-Aleutian subduction zone, and by lateral escape of the forearc to the southwest, due to collision and indentation of the Yakutat terrane 300 km to the east of the basin.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Potential seismic hazards and tectonics of the upper Cook Inlet basin, Alaska, based on analysis of Pliocene and younger deformation |
| Series title | Geological Society of America Bulletin |
| DOI | 10.1130/0016-7606(2000)112<1414:PSHATO>2.0.CO;2 |
| Volume | 112 |
| Issue | 9 |
| Year Published | 2000 |
| Language | English |
| Publisher | Geological Society of America |
| Contributing office(s) | Alaska Science Center, Alaska Science Center Geology Minerals, Geologic Hazards Science Center |
| Description | 16 p. |
| First page | 1414 |
| Last page | 1429 |
| Country | United States |
| State | Alaska |
| Other Geospatial | Cook Inlet basin |
| Google Analytic Metrics | Metrics page |