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NEW METHODS FOR DETECTING EARTHQUAKE SWARMS AND TRANSIENT MOTION TO CHARACTERIZE HOW FAULTS SLIP

Holtkamp, Stephen Gregg
http://rave.ohiolink.edu/etdc/view?acc_num=miami1369741772

Abstract Details

2013, Doctor of Philosophy, Miami University, Geology and Environmental Earth Science.
The possibility for earthquakes to be triggered by or related to each other or an external “aseismic” factor impacts hazard assessment and mitigation. With this dissertation, we have worked towards improvement of observation and modeling for earthquake swarms, slow slip associated with episodic tremor and slip, and human induced seismicity. Each of these cases has the potential to influence when, where, and to what size an earthquake can grow. First, we produce geodetic inversions of slow slip events in Cascadia, and highlight two unique instances where slow slip and non-volcanic tremor are not spatially correlated. In Cascadia, the correlation is so strong that tremor has become an accepted proxy for slow slip, but we show that this is not always the case. We show that the depth of the tremor may resolve this discrepancy. Second, we conduct a search for earthquake swarms along major convergent margins and find 180 swarms occurring within the seismogenic megathrust. We find evidence that these swarms are driven by aseismic slip, and may be broadly anti-correlated with large, destructive megathrust events. Third, we investigate this apparent anti-correlation with large megathrust events in detail by examining all Mw>7.5 earthquakes and classify them based on their relationship to swarm-generating regions of the interface. We find that large earthquakes are five times more likely to terminate in swarm regions than they are to propagate through swarm regions, suggesting that swarm regions are delineating where megathrusts are segmented. Lastly, we develop a multiple station waveform cross-correlation technique to investigate local to regional seismic data which is able to detect earthquakes several orders of magnitude smaller than traditional techniques. We use this technique to create a ~20 fold increase in detected seismicity during the 2011 Youngstown, Ohio earthquake sequence, allowing us to go well beyond the standard “proximity test” and conclusively establish a causal relation between wastewater injection and earthquakes. In total, we expect this dissertation to improve our understanding of how these unique seismic sequences occur, what their underlying mechanism is, and how they may be related to the damaging earthquakes sought out by the hazard assessment community.
Michael Brudzinski, PhD (Advisor)
Brian Currie, PhD (Committee Member)
Elizabeth Widom, PhD (Committee Member)
Jonathan Levy, PhD (Committee Member)
Zhigang Peng, PhD (Committee Member)
Michael Pechan, PhD (Committee Member)
118 p.
Geophysics
Seismology; Geodesy; Geophysics; Earthquake Swarms; Aseismic Slip; Induced Seismicity; Triggered Seismicity; Subduction Zones

Recommended Citations

Citations

  • Holtkamp, S. G. (2013). NEW METHODS FOR DETECTING EARTHQUAKE SWARMS AND TRANSIENT MOTION TO CHARACTERIZE HOW FAULTS SLIP [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1369741772

    APA Style (7th edition)

  • Holtkamp, Stephen. NEW METHODS FOR DETECTING EARTHQUAKE SWARMS AND TRANSIENT MOTION TO CHARACTERIZE HOW FAULTS SLIP. 2013. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1369741772.

    MLA Style (8th edition)

  • Holtkamp, Stephen. "NEW METHODS FOR DETECTING EARTHQUAKE SWARMS AND TRANSIENT MOTION TO CHARACTERIZE HOW FAULTS SLIP." Doctoral dissertation, Miami University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1369741772

    Chicago Manual of Style (17th edition)

miami1369741772
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© 2013, all rights reserved.
This open access ETD is published by Miami University and OhioLINK.