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About John Jasbinsek: I am a geophysicist kept off the street courtesy of the Physics Department at California Polytechnic State University, San Luis Obispo.

If you are a student interested in a senior project or other independent study project please use the links above to see an overview of recent research projects.

Teaching


Courses I frequently teach are listed below. Some might even have working websites!

  • GEOL 201 Physical Geology
  • GEOL 206 Geologic Excursions
  • GEOL 241 Physical Geology Laboratory
  • GEOL 305 Seismology and Earth Structure
  • GEOL 420 Field Geophysics
  • PHYS 410 Physics of Soild Earth
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    Geophysical Research at Cal Poly San Luis Obispo


    I work in and supervise student research and senior projects in the areas of near-surface geophysics (hydrogeology) and global seismology. If you are a student and want to discuss opportunities in these areas feel free to send me an email or stop by my office (Baker Science Room 520) sometime.

    Near-surface Geophysics & Hydrogeology

    I primarily use electrical resistivity tomography to image near-surface geologic structures such as faults, folds, and stratigraphy; the typical application to infer aquifer structure and groundwater resources. In addition, other methods include induced polarization (IP) and self potential (SP), and seismic refraction tomography (SRT).

    Below is a two-dimensional electrical resistivity tomography (2D ERT) image collected along the Rinconada Fault in Paso Robles, CA. The southwest side (on right) is shale (exposed at surface) and the northeast side is made up of decomposed granite from the Salinian Block at the surface, which is presumably fractured at depth. Here we are trying to evaluate whether the fractured granite could act as an aquifer for the landowner.

    Data was collected by the Fall 2022 Applied Geophysics class using the mighty SuperStingR8 resistivity meter and 56 electrodes at six-meter spacing.

    Global Seismology

    Global seismology analyzes earthquake waves to infer/constrain the earth’s deep interior structure and state.

    Ultra-low Velocity Zones (ULVZ) at the Core-mantle Boundary

    Currently students have been exploring ultra-low velocity zones (ULVZ) at earth’s core-mantle boundary at 2,900 km depth using PcP and ScP seismic phases.

    The image below shows a model fit (red: data, blue: synthetic) of ultra-low velocity zone structure using PcP phase arrivals recorded at a high density array.

    The PcP phase arrival shows an ultra-low velocity zone structure at the core-mantle boundary. The best fitting one-dimensional ULVZ model has a thickness of 6.5 km and S-wave velocity decrement of 27.5%.

    Interestingly, no density increase or P-wave velocity decrement is needed; in fact, increasing the density and/or decreasing P-wave velocity immediately begins to degrade model fit (with the important caveat that these are only one-dimensional models!).

    Core-rigidity Zones

    Students are also modeling ScP waves for anomalous structure at the core-mantle boundary. The image below shows a stack (linear and phase-weighted) of P-waves and ScP-waves. The ScP response is suggestive of a core-rigidity zone (CRZ) structure (Rost and Revenaugh 2001), or → direct link to PDF.

    Some observations of a CRZ structure were also detected with ultra-low velocity zone (ULVZ) observations (Rost and Revenaugh 2003) → freely downloadable from Journal of Geophysical Research.

    The above two references are the only previous CRZ observations in the literature I am aware of.

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    Photo Albums


    Course (and maybe eventually field research) photo albums.

    Applied Geophysics (GEOL 420)

    Fall 2024   Fall 2023   Fall 2022   Fall 2021  
    Fall 2020   Fall 2019   Fall 2018   Fall 2017  
    Fall 2016   Fall 2015   Fall 2014

    Seismology & Earth Structure (GEOL 305)

    Spring 2024   Spring 2022   Winter 2020   Fall 2015

    Physical Geology Laboratory (GEOL 241)

    Spring 2023   Spring 2021   Winter 2021   Spring 2019  
    Spring 2018   Spring 2017  

    Geologic Excursions (GEOL 206)

    Fall 2021   Spring 2019   Spring 2018   Fall 2016  

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