S41B-2744
Anisotropic 3-D Crustal Velocity Structure of Idaho/ Oregon from a Joint Inversion of Group and Phase Velocities of Love and Rayleigh Waves from Ambient Seismic Noise: Results from the IDOR Project
Thursday, 17 December 2015
Poster Hall (Moscone South)
Paul M Bremner, University of Florida-Geological Sciences, Gainesville, FL, United States, Mark P Panning, Univ of FL-Geological Sciences, Gainesville, FL, United States, Ray Russo, University of Florida, Department of Geological Sciences, Gainesville, FL, United States, Victor I Mocanu, University of Bucharest, Dept. of Geophysics, Bucharest, Romania, Adrian Christian Stanciu, Virginia Polytechnic Institute and State University, Department of Geosciences, Blacksburg, VA, United States, Megan E Torpey, University of Florida, Ft Walton Beach, FL, United States, Sutatcha Hongsresawat, University of Florida, Gainesville, FL, United States and John C VanDecar, Nature Publishing Group, London, United Kingdom
Abstract:
We present new 3-D radially anisotropic and isotropic crustal velocity models beneath central Idaho and eastern Oregon. We produced the velocity models from Love and horizontal component Rayleigh wave group and phase velocity measurements on the IDaho/ORegon (IDOR) Passive seismic network, 86 broadband seismic stations, dataset using ambient noise tomography and the methods of Gallego et. al (2010) and Lin et. al (2008). We calculated inter-station group/phase velocities in narrow frequency bands from travel-time measurements of the rotated stacked horizontal component cross-correlations (bandpass filtered between 2 and 30 seconds), which we used to invert for velocity structure beneath the network. We derived group and phase velocity maps for each frequency band using the damped least-squares inversion method of Tarantola (2005), and then jointly inverted for velocity with depth. Moho depths are prescribed in the joint inversions based on receiver functions, also from the IDOR seismic data, and provides a starting crustal velocity model. Goals of our work include refining models of crustal structure in the accreted Blue Mountain terranes in the western study area; determining the depth extent of the Salmon River Suture/West Idaho Shear Zone (WISZ), which crosses north-south through the middle of the network; determining the architecture of the Idaho batholith, an extensive largely crustal-derived pluton; and examining the nature of the autochthonous (?) North American crust and lithosphere beneath and east of the batholith.
