EarthScope MT: The Oregon Pilot Project

The IRIS consortium (http://www.iris.edu), in conjunction with the ElectroMagnetic Studies of the Continents (EMSOC) consortium (http://emsoc.ucr.edu/emsoc/) is installing temporary magnetotelluric (MT) stations across the contiguous US as part of EarthScope/USArray. A regional lithospheric/asthenospheric conductivity map of the United States is a high priority product for EarthScope. These mantle conductivity models will complement the seismic tomography images of the structure beneath North America. In some cases, conductivity provides constraints that are difficult to provide from seismic data: for example, conductivity is particularly sensitive to the water content of the mantle. Joint interpretation of conductivity, velocity, and attenuation is beginning to provide better constraints on composition and physicochemical state than can analysis of any one property alone, and the ElectroMagnetic (EM) community anticipates that further development in this area will continue. During the Summer of 2006, IRIS, University of California Riverside, University of Oregon, Oregon State University and GSY-USA deployed 10 MT systems at 30 sites uniformly distributed throughout Oregon east of the Cascades, coincident with the High Lava Plains and Wallowa temporary seismic experiments. This pilot project was conducted to determine the costs and challenges of routinely deploying state-of-the-art MT systems by a professionally managed services contractor with scientific oversight provided by a university group. This poster discusses the lessons learned, and presents a preliminary analysis of the data.