Physical Sciences and Mathematics | Open Access Articles

Reverse-Time Migration-Based Reflection Tomography Using Teleseismic Free Surface Multiples, S. Burdick, M. V. De Hoop, R. D. Van Der Hilst

Environmental Science and Geology Faculty Research Publications

Converted and multiply reflected phases from teleseismic events are routinely used to create structural images of the crust–mantle boundary (Moho) and the elasticity contrasts within the crust and upper mantle. The accuracy of these images is to a large extent determined by the background velocity model used to propagate these phases to depth. In order to improve estimates of 3-D velocity variations and, hence, improve imaging, we develop a method of reverse-time migration-based reflection tomography for use with wavefields from teleseismic earthquakes recorded at broad-band seismograph arrays. Reflection tomography makes use of data redundancy—that is, the ability to generate numerous …

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Coevolution Of Nonlinear Trends In Vegetation, Soils, And Topography With Elevation And Slope Aspect: A Case Study In The Sky Islands Of Southern Arizona, Jon D. Pelletier, Greg A. Barron-Gafford, David D. Breshears, Paul D. Brooks, Jon Chorover, Matej Durcik, Ciaran J. Harman, Travis E. Huxman, Kathleen A. Lohse, Rebecca Lybrand, Tom Meixner, Jennifer C. Mcintosh, Shirley A. Papuga, Craig Rasmussen, Marcel Schaap, Tyson L. Swetnam, Peter A. Troch

Environmental Science and Geology Faculty Research Publications

Feedbacks among vegetation dynamics, pedogenesis, and topographic development affect the “critical zone”—the living filter for Earth’s hydrologic, biogeochemical, and rock/sediment cycles. Assessing the importance of such feedbacks, which may be particularly pronounced in water-limited systems, remains a fundamental interdisciplinary challenge. The sky islands of southern Arizona offer an unusually well-defined natural experiment involving such feedbacks because mean annual precipitation varies by a factor of five over distances of approximately 10 km in areas of similar rock type (granite) and tectonic history. Here we compile high-resolution, spatially distributed data for Effective Energy and Mass Transfer (EEMT: the energy available to drive …

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The Effect Of Atmospheric Water Vapor On Neutron Count In The Cosmic-Ray Soil Moisture Observing System, R. Rosolem, W. J. Shuttleworth, M. Zreda, T. E. Franz, X. Zeng, S. A. Kurc

Environmental Science and Geology Faculty Research Publications

The cosmic-ray method for measuring soil moisture, used in the Cosmic-Ray Soil Moisture Observing System (COSMOS), relies on the exceptional ability of hydrogen to moderate fast neutrons. Sources of hydrogen near the ground, other than soil moisture, affect the neutron measurement and therefore must be quantified. This study investigates the effect of atmospheric water vapor on the cosmic-ray probe signal and evaluates the fast neutron response in realistic atmospheric conditions using the neutron transport code Monte Carlo N-Particle eXtended (MCNPX). The vertical height of influence of the sensor in the atmosphere varies between 412 and 265m in dry and wet …

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Full-Text Articles in Physical Sciences and Mathematics

Reverse-Time Migration-Based Reflection Tomography Using Teleseismic Free Surface Multiples, S. Burdick, M. V. De Hoop, R. D. Van Der Hilst

Environmental Science and Geology Faculty Research Publications

Environmental Science and Geology Faculty Research Publications

The Effect Of Atmospheric Water Vapor On Neutron Count In The Cosmic-Ray Soil Moisture Observing System, R. Rosolem, W. J. Shuttleworth, M. Zreda, T. E. Franz, X. Zeng, S. A. Kurc

Environmental Science and Geology Faculty Research Publications