New insights into the slip budget at Nankai: an iterative approach to estimate coseismic slip and afterslip

Abstract Postseismic Global Navigation Satellite System (GNSS) time series followed by megathrust earthquakes can be interpreted as a result of afterslip on the plate interface, especially in its early phase. Afterslip is a stress release process accumulated by adjacent coseismic slip and can be considered a recovery process for future events during earthquake cycles. Spatio-temporal evolution of afterslip often triggers subsequent earthquakes through stress perturbation. Therefore, it is important to quantitatively capture the spatio-temporal evolution of afterslip and related postseismic crustal deformation and to predict their future evolution with a physics-based simulation. We developed an adjoint data assimilation method, which directly assimilates GNSS time series into a physics-based model to optimize the frictional parameters that control the slip behavior on the fault. The developed method was validated with synthetic data. Through the optimization of frictional parameters, the spatial distributions of afterslip could roughly (but not in detail) be reproduced if the observation noise was included. The optimization of frictional parameters reproduced not only the postseismic displacements used for the assimilation, but also improved the prediction skill of the following time series. Then, we applied the developed method to the observed GNSS time series for the first 15 days following the 2003 Tokachi-oki earthquake. The frictional parameters in the afterslip regions were optimized to A–B ~ O(10 kPa), A ~ O(100 kPa), and L ~ O(10 mm). A large afterslip is inferred on the shallower side of the coseismic slip area. The optimized frictional parameters quantitatively predicted the postseismic GNSS time series for the following 15 days. These characteristics can also be detected if the simulation variables can be simultaneously optimized. The developed data assimilation method, which can be directly applied to GNSS time series following megathrust earthquakes, is an effective quantitative evaluation method for assessing risks of subsequent earthquakes and for monitoring the recovery process of megathrust earthquakes.

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Fractal and Fractional Derivative Modelling of Material Phase Change

Fractal and Fractional ◽

10.3390/fractalfract4030046 ◽

2020 ◽

Vol 4 (3) ◽

pp. 46

Author(s):

Harry Esmonde

Keyword(s):

Transfer Functions ◽

Type Model ◽

Material Structure ◽

Iterative Approach ◽

Response Functions ◽

Physical Processes ◽

Ethyl Vinyl ◽

Solid Models ◽

Liquid Type ◽

Model Phase

An iterative approach is taken to develop a fractal topology that can describe the material structure of phase changing materials. Transfer functions and frequency response functions based on fractional calculus are used to describe this topology and then applied to model phase transformations in liquid/solid transitions in physical processes. Three types of transformation are tested experimentally, whipping of cream (rheopexy), solidification of gelatine and melting of ethyl vinyl acetate (EVA). A liquid-type model is used throughout the cream whipping process while liquid and solid models are required for gelatine and EVA to capture the yield characteristic of these materials.

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Iterative approach to strong turbulence theory

The Physics of Fluids ◽

10.1063/1.863140 ◽

1980 ◽

Vol 23 (7) ◽

pp. 1301 ◽

Cited By ~ 2

Author(s):

Georg Knorr ◽

Michael Mond

Keyword(s):

Turbulence Theory ◽

Iterative Approach ◽

Strong Turbulence

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An iterative approach to graph irregularity strength

Discrete Applied Mathematics ◽

10.1016/j.dam.2010.02.003 ◽

2010 ◽

Vol 158 (11) ◽

pp. 1189-1194 ◽

Cited By ~ 5

Author(s):

Michael Ferrara ◽

Ronald Gould ◽

Michał Karoński ◽

Florian Pfender

Keyword(s):

Iterative Approach ◽

Irregularity Strength

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THE ENERGY EIGENVALUES OF THE TWO DIMENSIONAL HYDROGEN ATOM IN A MAGNETIC FIELD

International Journal of Modern Physics E ◽

10.1142/s021830130600482x ◽

2006 ◽

Vol 15 (06) ◽

pp. 1263-1271 ◽

Cited By ~ 22

Author(s):

A. SOYLU ◽

O. BAYRAK ◽

I. BOZTOSUN

Keyword(s):

Magnetic Field ◽

Hydrogen Atom ◽

Iteration Method ◽

Weak Magnetic Field ◽

The Other ◽

Asymptotic Iteration Method ◽

Iterative Approach ◽

Two Dimensional ◽

Energy Eigenvalues ◽

The Magnetic Field

In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the case with no magnetic field analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for n=2-10 and m=0-1 states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.

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