Earth Planets Space, Vol. 57 (No. 8), pp. 781-793, 2005
R. W. Saltus1, R. J. Blakely2, P. J. Haeussler3, and R. E. Wells4
1U.S. Geological Survey, Mail Stop 964, Denver, CO 80225-0046, USA
2U.S. Geological Survey, Mail Stop 989, 345 Middlefield Road, Menlo Park, CA 94025, USA
3U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508, USA
4U.S. Geological Survey, Mail Stop 973, 345 Middlefield Road, Menlo Park, CA 94025, USA
(Received January 30, 2004; Revised October 27, 2004; Accepted October 27, 2004)
High-resolution aeromagnetic surveys over forearc basins can detect faults and folds in weakly magnetized sed-iments, thus providing geologic constraints on tectonic evolution and improved understanding of seismic hazards in convergent-margin settings. Puget Sound, Washington, and Cook Inlet, Alaska, provide two case histories. In each lowland region, shallow-source magnetic anomalies are related to active folds and/or faults. Mapping these structures is critical for understanding seismic hazards that face the urban regions of Seattle, Washington, and Anchorage, Alaska. Similarities in aeromagnetic anomaly patterns and magnetic stratigraphy between the two regions suggest that we can expect the aeromagnetic method to yield useful structural information that may contribute to earth-hazard and energy resource investigations in other forearc basins.
Key words: Aeromagnetic, susceptibility, seismic hazards.