GPS studies of the US Pacific Northwest

Collaborators: Charles Williams (GNS Science), Ani Tikku (Exxon), Suzette Payne (INL), Tony Qamar (UW), Bob King (MIT), Giovanni Sella (Northwestern), Todd Williams (Humboldt State)

Students: Peter Zwick, Colleen Stevens, Ellen Robey, Paul Wallenberger, Cathleen Donovan, Albert Nummelin, Cheryl Johnson*, Maureen Long*, Jesse Vollick*, Anna Smith*, Kristin Fixx*, Jake Schowalter*, Karin Lackmann*, Jackie Krajewski*, Jon Ganz*, Andy Ratigliano*, Emily Witthaus*, Matt Lancaster*, Marc Nabelek+, Hanya Zwick+, Peter Arlein+, Michal Zwick+, Chris O'Brien+

Volunteers: Cheryl McCaffrey, Beth Walton, Sara McCaffrey

* - undergraduate students, + - highschool students

We are monitoring geodetic motions in the US Pacific Northwest to estimate locking on the Cascadia subduction zone, upper plate strain, and the motion of the Pacific Northwest relative to North America. Starting in 1996, in collaboration with Oregon State University we occupied the network between the coast and Sisters OR at the latitude of Corvallis from 1996 to 1999. This region was originally surveyed by the USGS in 1992 and 1994. In 1999 we extended the network (click here) northward to the Portland region. In 2000 (click here) we occupied sites in eastern Oregon and collobarated with the University of Washington to re-occupy sites in western Washington State. In 2001 (click here) we occupied sites in northern Oregon and collobarated with the University of Washington to re-occupy sites in Washington State and with the Pacific Geoscience Center (Geol. Survey of Canada) to establish GPS sites in SW British Columbia. In 2008-2012 we expanded the network into Idaho with Idaho National Lab.

2015 GPS velocity field map

We are also re-processing data collected by the USGS, Cascades Volcano Observatory, and National Geodetic Survey to include in our velocity solution.

Velocity fields:

We process regional continuous network data using GAMIT/GLOBK.

Some maps:

Field photos:

Publications and reports related to Oregon and Cascadia.

More information about Oregon tectonic studies can be found at these sites:

This work is funded by the US Geological Survey and National Science Foundation.