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Multi-scale logarithmic transient models for postseismic displacements and the physical causes of postseismic transient deformation

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2018, Doctor of Philosophy, Ohio State University, Geodetic Science.
The earthquake deformation cycle has three phases referred to as the interseismic, coseismic and postseismic phases. Two main classes of mechanism associate with postseismic transient deformation: Afterslip and the mechanism invokes the relaxation of stress changes induced by coseismic displacements which includes poroelastic deformation and bulk viscoelastic relaxation. Sobrero (2018) concluded that the early postseismic transient behavior is dominated by afterslip by showing the postseimic transients tend to decay logarithmically in time rather than exponentially. This study further investigated the notion that postseismic deformation following the M9.1 Tohoku earthquake of 2011 is dominated by the afterslip. The time series of 1148 GPS stations covering the entire Japan are applied with the bilogarithmic transient model. Two different models are applied and compared: using different time scales for each GPS time series (Model 1) and using a shared set of transient timescales (T1 and T2) (Model 2). In principle, if the postseismic deformation is dominated by the afterslip, since all GPS stations are responding to afterslip on the same fault, it ought to be possible to obtain a very good fit obtained using a single pair of timescale parameters associated with the fault rather than customized parameters tied to each GPS station. Our result only shows a slightly better fit for Model 1 than Model 2. Comparing with the situation that the Model 1 introduces much more degrees (2294) of freedom than the Model 2, the slightly better fit could be explained by the fact that each GPS time series is contaminated by colored noise, which implies temporally-correlated noise. Therefore, providing each station trajectory model with adjustable timescale parameters would allow it to better fit the structured positioning noise as well as the postseismic signal.
Michael Bevis (Advisor)
134 p.

Recommended Citations

Citations

  • Wang, F. (2018). Multi-scale logarithmic transient models for postseismic displacements and the physical causes of postseismic transient deformation [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534341970725629

    APA Style (7th edition)

  • Wang, Fei. Multi-scale logarithmic transient models for postseismic displacements and the physical causes of postseismic transient deformation. 2018. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1534341970725629.

    MLA Style (8th edition)

  • Wang, Fei. "Multi-scale logarithmic transient models for postseismic displacements and the physical causes of postseismic transient deformation." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534341970725629

    Chicago Manual of Style (17th edition)