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Simulation of the 2016 Tottori (Mw 6.1) earthquake using a dynamic source model
Hronek, Martin ; Gallovič, František (advisor) ; Premus, Jan (referee)
We perform a parametric study for simple elliptical dynamic models of rupture propa- gation. We simulate the earthquake from the central part of Japanese prefecture Tottori in 2016 using a code for a simulation of the rupture propagation developed at the Depart- ment of Geophysics assuming the classic linear slip-weakening friction law. We evaluate the match of synthetic seismograms with the observed data. From different models we choose the one best fitting the data. The values of seismic moment, slip distribution, stress drop, radiated energy and radiation efficiency are close to the ones from published articles. In conclusion we point out some possible sources of inaccuracies in modelling and suggest improvements for the future. 1
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Joint inverse modeling of coseismic and postseismic slip of the 2014 South Napa, California, earthquake
Premus, Jan ; Gallovič, František (advisor) ; Burjánek, Jan (referee) ; Tinti, Elisa (referee)
Title: Joint inverse modeling of coseismic and postseismic slip of the 2014 South Napa, California, earthquake Author: Jan Premus Department: Department of Geophysics Supervisor: prof. František Gallovič, Department of Geophysics Abstract: Slip at tectonic faults spans a wide range of time scales, from tens of seconds of earthquake coseismic rupture to months of aseismic afterslip, recorded in seismograms and geodetic data. The two slip phenomena are often studied separately, focusing on kinematic aspects. We introduce a Bayesian method for physics-based joint inverse modeling of an earthquake slip and afterslip, employ- ing a unifying rate-and-state friction law. To simulate the rupture propagation, we develop an efficient finite-difference open-source code FD3D TSN. GPU ac- celeration of the code yields speed-up by a factor of 10 with respect to a CPU, enabling hundreds of thousands of earthquake simulations in a reasonable time. We also implement a quasi-dynamic afterslip simulation using a boundary inte- gral element method. We apply the Bayesian dynamic inversion to the 2014 Mw 6.0 Napa earthquake. We reveal the dynamics of coseismic and postseismic slip in terms of stress and friction in a unified model, reconciling previous disjunctive analyses of the event. We show that the two types of slip are mostly...
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Development of effective code for earthquake dynamic source simulations
Premus, Jan ; Gallovič, František (advisor) ; Zahradník, Jiří (referee)
Title: Development of effective code for earthquake dynamic source simulations Author: Bc. Jan Premus Department: Department of Geophysics Supervisor: doc. RNDr. František Gallovič, Ph.D, Department of Geophysics Abstract: Dynamic rupture modeling coupled with strong motion data fitting offers an insight into physical mechanisms behind earthquake sources [Gallovic et al., 2019]. Running a large number of dynamic model simulations is required due to the nonlinearity of the inverse problem. The goal of this Thesis is a development of an efficient forward solver for the dynamic inversions. The fi- nite difference staggered grid code FD3D by Madariaga and Olsen [1998] served as a basis for the development, offering sufficient speed, but rather low accu- racy. Traction at split node implementation of the fault boundary condition and perfectly matched layers as the absorbing boundary condition were required to obtain desirable accuracy. In addition to the slip weakening friction law, fast ve- locity weakening friction law has been implemented, increasing the applicability of the code. We test the new code FD3D TSN using USGS/SCEC benchmarks TPV5 (slip-weakening friction) and TPV104 (fast rate weakening friction) [Harris et al., 2018], showing very good agreement with results calculated by advanced numerical...
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Theoretical description and simulation of polymer network formation
Premus, Jan ; Šomvársky, Ján (advisor) ; Dušek, Karel (referee)
One of methods for description of formation and structure of polymer ne- tworks is used in the work - combination of chemical kinetics and theory of branching processes (TVP) with correlations to neighbors. Main output of this work is computer program, whose purpose is setting up of rooted fragments of given size, differential equations for their concentrations and calculation of se- lected structural parameters using TVP. Gel points for systems formed by three and fourfunctional monomer and combination of two and threefunctional mono- mer were computated in this way. Chemical simulation of molecules was used as reference value. Larger correlation distance (larger size of fragments) led to more accurate results. Calculation of system parameters using TVP allowed study of gel parameters, concentrations of elastically active chains for all studied systems is shown in the work. 1
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