Physical Sciences and Mathematics Commons^™

Detection Of An Ultra Low Velocity Zone Beneath Central Mexico With Pcp Waveform Modeling, David James Buckley

Physics

PcP phases from a Guatemalan earthquake recorded at Nevada stations of the International seismic network (IM) display evidence of anomalous seismic structure at the core-mantle boundary (CMB); in particular, pre- and post-cursor phases to PcP and ScP. The data is examined for evidence of an ultra-low velocity zone (ULVZ) by identifying and modeling precursors to PcP. Precursory arrivals to PcP may be generated by the interaction of PcP with a thin layer above the core-mantle boundary (CMB). One-dimensional modeling demonstrates that standard earth models of the core-mantle boundary, which lack ULVZ structure, cannot produce the observed PcP data. …

Geoelectrical Detection Of Water Table Depth At Two Locations In The Los Osos Groundwater Basin, Hallie A. Douglas

Natural Resources Management and Environmental Sciences

The city of Los Osos sits on top of a coastal groundwater aquifer which is the sole supplier of all its residential, agricultural, and industrial water needs. Lacking a sewer system, the upper aquifer became progressively contaminated with nitrates over several decades. Groundwater pumping eventually shifted to the lower aquifer, however seawater intrusion of the lower aquifer caused by over-pumping has further degraded water quality. The Los Osos groundwater basin provides an excellent field region to examine the utility of geophysical methods for characterizing aquifer structure. In this study shallow (<20 >m) electrical resistivity imaging methods were performed at two …

Depth To Bedrock Estimations Using The H/V Spectral Ratio In The San Joaquin Valley, Tyler A. Morelli

Natural Resources Management and Environmental Sciences

Basin depth is a fundamental parameter in many types of geologic studies such as resource exploration and regional tectonic mapping. The Horizontal-to-Vertical Spectral Ratio (“H/V”) method has been successfully applied to estimating of basin depths up to several hundred meters. In this study the H/V method is applied to the deep basins on the western side of the San Joaquin Valley to determine the thickness of the sedimentary layers and depth to bedrock. Microtremor data from Earthscope Seismic Array stations are ideal to test the accuracy of the H/V method on deeper basins because the data is of high-quality and …

Estimates Of The Density Contrast At Earth’S Inner-Core Boundary Beneath Central Mexico, Wade Kelley

Physics

Seismograms recorded in the western United States from a Guatemalan earthquake are examined for matching pairs of PKiKP and PcP waveforms for use in estimating the density contrast at earth’s inner-core boundary via a PKiKP/PcP amplitude ratio analysis. Examination of waveforms from the SN, SC, TA, US and CI arrays finds 68 visually identifiable PKiKP and PcP pairs from which 17 were judged to be of sufficient quality (low signal-to-noise ratio) for use in the PKiKP/PcP amplitude ratio analysis. The epicentral distance range of the selected data spans epicentral distances from 22 – 37 degrees inside of which stations are …

Seismic Detection Of A Low-Velocity Layer Atop The 410-Km Discontinuity: Verification Of An Electromagnetically Detected Layer Of Partial-Melt Atop The 410-Km Discontinuity Beneath Se Arizona, Dwight W. Townsend

Physics

No abstract provided.

Paleomagnetism And Investigation Of 40 Ma Lavas, Liverpool Range, New South Whales, Australia, Nathan M. Padilla

Physics

The main focus of this project is the continued study of a reversal of the earth’s magnetic field recorded from lavas in the Liverpool Range of New South Whales, Australia. This reverse-to-normal transition, recently dated at ~40 Ma, was first reported in Nature in 1986. [2] In March 2011 some 200+ cores were drilled from several sections about the volcanic range—Jemmy’s Creek, Bald Hill, Rock Creek, Yarraman, and Coolah Tops Road. Here we focus on paleomagnetic findings from samples drilled from the most extensive section, that being along the trail near Jemmy’s Creek. Results from alternating field demagnetization show the …

Groundwater Research In Middle Earth, Thomas Lapoint

Liberal Arts and Engineering Studies

My senior project focused on studying saltwater intrusion in a coastal town of New Zealand. I feel lucky that I was able to travel to such a distant place, conduct research that was insightful and interesting, and immerse myself in an international culture all in the name of my education. As a Liberal Arts and Engineering Studies student, I aim to analyze not only the cultural differences and similarities that the foreign environment offers to me but also the detailed, technical, engineering aspect of my research. I believe that my education should be approached with a well rounded perspective that …

Probabilistic Fault Displacement Hazard Analysis For Reverse Faults And Surface Rupture Scale Invariance, Zachary E. Ross

Master's Theses

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px 'Times New Roman'}

A methodology is presented for evaluating the potential surface fault displacement on reverse faults in a probabilistic manner. This methodology follows the procedures put forth for Probabilistic Fault Displacement Hazard Analysis (PFDHA). Empirical probability distributions that are central to performing a PFDHA are derived from field investigations of reverse faulting events. Statistical analyses are used to test previously assumed properties of scale invariance with respect to magnitude for normalized displacement. It is found that normalized displacement is statistically invariant with respect to magnitude and focal mechanism, allowing for the …

Detrital Zircon Geochronology For Neoproterozoic To Cambrian Sediment Sources Of The Deep Creek Range And The Pilot Range In The Southwestern United States, Kaysea Perry

Earth and Soil Sciences

Detrital zircon studies of miogeoclinal sediments can help provide a deeper look into the mechanisms leading to continental breakup by studying the evolution of the continental margin of North America. Few detrital zircon studies have been conducted to support previous research and theories about the sedimentation of the Miogeocline from the Neoproterozoic to the Cambrian. Studies targeted at the Basin and Range province of the western United States show a trend of increasing local sediment sources. We analyzed detrital zircons from the Pilot and Deep Creek Ranges in Nevada and Utah via LA-MC-ICP-MS at the University of Arizona LaserChron Center …