HR: 10:20h
AN: GP32A-01 INVITED    [Abstracts]
TI: EMSCOPE – Electromagnetic Component of EarthScope Backbone and Transportable Array Experiments 2006-2008
AU: Egbert, G
EM: egbert@coas.oregonstate.edu
AF: Oregon State University, College of Oceanic and Atmospheric Science, 104 COAS Admin Bldg, Oregon State University, Corvallis, OR 97331-5503, United States
AU: Evans, R
EM: revens@whoi.edi
AF: Woods Hole Oceanographic Institution, Department of Geology and Geophysics Woods Hole MA, Woods Hole, MA 02543, United States
AU: Ingate, S
EM: shane@iris.edu
AF: IRIS Incorporated Research Institutions for Seismology, 1200 New York Ave NW Suite 800, Washington, DC 20005, United States
AU: * Livelybrooks, D
EM: dlively@uoregon.edu
AF: University of Oregon, Department of Physics, University of Oregon, Eugene, OR 97403, United States
AU: Mickus, K
EM: kevinMickus@MissouriState.edu
AF: Missouri State University, Department of Geography, Geology and Planning, Springfield, MO 65897, United States
AU: Park, S
EM: skpark@ucr.edu
AF: University of California Riverside, Institute of Geophysics and Planetary Physics, 2007 Geology, University of California Riverside, Riverside, CA 92521, United States
AU: Schultz, A
EM: adam@coas.oregonstate.edu
AF: Oregon State University, College of Oceanic and Atmospheric Science, 104 COAS Admin Bldg, Oregon State University, Corvallis, OR 97331-5503, United States
AU: Unsworth, M
EM: unsworth@ualberta.phys.edu
AF: University of Alberta, Department of Physics, University of Alberta, Edmonton, AB T6G 2J1, Canada
AU: Wannamaker, P
EM: pewanna@egi.utah.edu
AF: University of Utah, Energy & Geoscience Institute, University of Utah, Salt Lake City, UT 84108, United States
AB: USArray (http://www.iris.edu/USArray) in conjunction with EMSOC (Electromagnetic Studies of the Continents) (http://emsoc.ucr.edu/emsoc) is installing magnetotelluric (MT) stations as part of Earthscope. The MT component of Earthscope consists of permanent (Backbone) and transportable long period stations to record naturally occurring, time varying electric and magnetic fields to produce a regional lithospheric/asthensospheric electrical conductivity map of the United States. The recent arrival of 28 long period MT instruments allows for the final installation of the Backbone stations throughout the US and yearly transportable array studies. The Backbone MT survey consists of 7 stations spaced throughout the continental US with preliminary installation at Soap Creek, Oregon; Parkfield, California; Braden, Missouri and Socorro, New Mexico.Siting and permitting are underway or completed at stations in eastern Montana, northern Wisconsin and Virginia. These stations will be recording for at least five years to determine electrical conductivities at depths that extend into the mantle transition zone. The first transportable array experiment was performed in the summer and fall of 2006 in central and eastern Oregon (Oregon Pilot Project) using equipment loaned from EMSOC. Thirty-one long period MT stations were recorded with 14 to 21 day occupations. Preliminary 3D inverse models indicate several lithospheric electrical conductivity anomalies including a linear zone marked by low-high conductivity transition along the Klamath-Blue Mountain Lineament associated with a linear trend of gravity minima. High electrical conductivity values occur in the upper crust under the accreted terrains in the Blue Mountains region. The second transportable array experiment was performed in the summer and fall of 2007 and completes coverage of the Oregon, Washington, and western Idaho, targeting the Cascadia subduction zone, Precambrian boundaries, and sub-basalt lithologies. The 2008 transportable MT experiment will focus on the Snake River Plain and the Yellowstone Hot Spot. The disposition of future USArray magnetotelluric geotransects will be the subject of an upcoming NSF-supported planning workshop. Time series are available now from the IRIS data center (www.iris.edu/data), and magnetotelluric transfer functions will soon be available.
DE: 1515 Geomagnetic induction
DE: 8110 Continental tectonics: general (0905)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting