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Published byRosamund Jordan Modified over 8 years ago
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Earthscope in the Northern U.S. Rockies: Tectonic Targets and Passive-Source Seismology Weapons * R. M. Russo Dept. of Geological Sciences University of Florida Gainesville, FL 32611 R. M. Russo Dept. of Geological Sciences University of Florida Gainesville, FL 32611 * (Or how I learned to stop worrying and love earthquakes)
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Geologic Targets What is the craton shape, from surface down? What is relief – if any – on craton bottom? Do the wide Mz and Cz magmatic belts at the surface still have expressions at depth? Can distribution, styles of surface deformation be related to upper mantle structures? - cratonization, belt rifting, accretion, Sevier & Laramide shortening, Eocene & Basin-Range extension Transition to Canadian Rockies Yellowstone plumbing system
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Seismologic Weapons: Body wave, surface wave tomography - teleseismic P, S waves; Rayleigh, Love waves - seismic velocities resolved, ~70-700 km depth Receiver functions - teleseismic P, local Ps phases & reverbs - S velocities resolved, ~60 km depth to surface - sharp seismic discontinuities revealed - fine anisotropic structure detailed
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Seismologic Weapons: Shear wave splitting - teleseismic S phases (SKS, SKKS, PKS, S) - seismic anisotropy resolved, ~0-410 km depth Seismic attenuation - any P and S wave pairs - attenuation along source-station path resolved - sensitive to temperature, not composition - 3-d attenuation structure
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Tomography
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Depth Resolution
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Receiver Functions From Stein & Wysession (2001)
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Seismic Anisotropy and Shear-Wave Splitting
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Splitting of an S phase: Particle Motion Correction
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Splitting of an S phase: Contoured Energy
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Upper Mantle Flow around the Ontong-Java Plateau Root
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Seismic Attenuation
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P and S Wave Windowing for Spectra
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Qs Calculation from Spectral Ratio Slope
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Qs at East European Platform stations
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Qs at Transylvania Basin stations
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Delamination Possible?
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Chile Ridge Subduction Subduction of the Chile Ridge occurs beneath southern SA. Ridge subduction has a profound effect on the overriding continent. It may also channel upper mantle flow, allowing a strong test of the ideas outlined in this talk.
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Chile Ridge Triple Junction & Slab Window
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Current UF-UChile Chile Ridge Triple Junction Passive Seismic Deployment
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