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Open-File Report O-23-05, Neotectonic Map of the Cascadia Margin


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Open-File Report O-23-05, Neotectonic Map of the Cascadia Margin, by Chris Goldfinger, Jeffrey Beeson, Chris Romsos and Jason R. Patton; 24 p. report.


This Neotectonic Map v. 7.2.2, is a revision of earlier versions that have been underway since the earliest versions found in Goldfinger (1994) and Goldfinger and others (1992), and is based on interpretations of bathymetric, sidescan sonar, core, drilling, and seismic reflection data and augmented by submersible and ROV observations compiled by the authors and references herein. The earlier versions, also used in publications referenced below, began with structural mapping of the Oregon margin.  Regions offshore Washington were added in Goldfinger and others (1997).  This version supersedes all earlier versions, and is a complete revision of the earlier work, using additional data in nearly all areas, and incorporating the California margin, as well as compiling and in some cases modifying earlier structural interpretations as noted.  The map does not include a complete mapping of the Canadian portion of the Cascadia margin as of this revision.



The neotectonic map attempts to differentiate the relative age of structures, despite the lack of definitive age control in most areas.  Instead, a scheme of relative age control is applied that is appropriate to the types of data and age information available.  The Cascadia margin is rich in geophysical data, collected over five decades, making a relative age strategy possible.  The geophysical data used vary widely in depth of penetration, quality, resolution, and navigational accuracy.  Thus the map itself unavoidably retains artifacts of this variability.  In some areas for example, sidescan sonar data are available with decimeter resolution, while other areas have only single-beam sounding data.  Inspection of the supporting data for the map will reveal these disparities.   The layers of supporting data include bathymetric grids, sidescan sonar and backscatter data, shaded relief imagery, geophysical trackline data and other supporting information.