TexasScholarWorks
    • Login
    • Submit
    View Item 
    •   Repository Home
    • UT Electronic Theses and Dissertations
    • UT Electronic Theses and Dissertations
    • View Item
    • Repository Home
    • UT Electronic Theses and Dissertations
    • UT Electronic Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Crustal seismic velocity models of Texas

    Thumbnail
    View/Open
    BORGFELDT-THESIS-2017.pdf (3.452Mb)
    Date
    2017-09-18
    Author
    Borgfeldt, Taylor Marie
    0000-0003-3850-5189
    Share
     Facebook
     Twitter
     LinkedIn
    Metadata
    Show full item record
    Abstract
    Our investigation distinguishes six distinct geologic regions within Texas and determines a preferred one-dimensional (1D) crustal structure for each. These models, which consist of flat layers of varying thicknesses and constant P and S-wave velocities in each layer, represent the best average crustal velocity structure. Our investigation is motivated by TexNet, a new statewide seismograph network, which will need more accurate regional crustal models to better locate earthquakes throughout the state. We test previously published models as well as newly generated models. The data used to develop the new models include previously used velocity models, geologic cross sections, refraction and reflection studies, sonic logs, receiver function results and any other geophysical survey information available for the specific regions. We test the accuracy of the various regional models by relocating earthquakes with Hypoinverse1.40 (HYPO1.40). The earthquake catalogs vary by region but meet standard criteria for quantity and quality of phases recorded. We relocate each set of regional earthquakes with all previously published and newly generated models and determine the preferred model by lowest RMS (root mean square) residuals, i.e., the differences in recorded and modeled travel times. To understand which layers most significantly affect observed travel times, we perform source-to-station ray tracing for available regional earthquakes with magnitudes larger than M2.6. We also use the arrival data to plot Wadati diagrams and find the regional Vp/Vs ratio, which is applied to the preferred P-velocity model to determine a preferred S-velocity model. Our data allow us to determine new preferred velocity models for four of the six regions (East Texas, Fort Worth Basin, Panhandle, and West Texas) and confirm a previously published model for two regions (Central and Gulf Coastal Plain). Central Texas does not have enough earthquake data or geophysical studies to determine a new model, so we suggest the continued use of the Mitchell and Landisman (1971) velocity model until new seismic data is available. The velocity model published by Cram, Jr. (1961) is the preferred model for regional earthquake location for the Gulf Coastal Plain.
    Department
    Geological Sciences
    Subject
    Velocity model
    Texas
    Crustal seismic velocity model
    Earthquake
    URI
    http://hdl.handle.net/2152/62597
    Collections
    • UT Electronic Theses and Dissertations

    University of Texas at Austin Libraries
    • facebook
    • twitter
    • instagram
    • youtube
    • CONTACT US
    • MAPS & DIRECTIONS
    • JOB OPPORTUNITIES
    • UT Austin Home
    • Emergency Information
    • Site Policies
    • Web Accessibility Policy
    • Web Privacy Policy
    • Adobe Reader
    Subscribe to our NewsletterGive to the Libraries

    © The University of Texas at Austin

     

     

    Browse

    Entire RepositoryCommunities & CollectionsDate IssuedAuthorsTitlesSubjectsDepartmentsThis CollectionDate IssuedAuthorsTitlesSubjectsDepartments

    My Account

    Login

    Statistics

    View Usage Statistics

    Information

    About Contact Policies Getting Started Glossary Help FAQs

    University of Texas at Austin Libraries
    • facebook
    • twitter
    • instagram
    • youtube
    • CONTACT US
    • MAPS & DIRECTIONS
    • JOB OPPORTUNITIES
    • UT Austin Home
    • Emergency Information
    • Site Policies
    • Web Accessibility Policy
    • Web Privacy Policy
    • Adobe Reader
    Subscribe to our NewsletterGive to the Libraries

    © The University of Texas at Austin