Yamada, Masayuki

A Ground Motion Simulation Coupled With An Eikonal Solver and Its Application With a Formula Using Isochrones Jumping Intensity

Abstract eng:
We describe three achievements for a ground motion simulation. First, we propose a kinematic modeling in which rupture delay time is governed by an eikonal equation on Riemannian manifold and develop a coupling method between the eikonal solver and a ground motion simulation. In general the rupture delay time is depending on the fault shape. So we derive the equation by considering the Riemannian metric of the fault surface and give a detailed discretization of its difference scheme to deal with a curved surface fault. Next, in order to explain the effect of spatially discontinuous non-uniformity of rupture velocity, we introduce an isochrones jumping intensity and obtain a new decomposed isochrones formula with mathematical rigor. It is known that the representation theorem with the Green’s function can be rewritten into an expression with a contour integral by the isochrones theory. The new formula says that the known isochrones formula for velocity can be decomposed into a trend component and a disturbance component. The disturbance component consists of the isochrones jumping intensity. Finally, by applying our ground motion simulation coupled with the eikonal solver and the decomposed isochrones formula, we investigate some relations between the non-uniformity of the rupture velocity and pulse-like disturbance of the ground motion velocity. Our simulations show that the disturbance of velocity waveform corresponds with that of rate of change of isochrones band area. It turns out that the pulse-like disturbance of velocity waveform occurs when isochrones move across the region where rupture velocity varies discontinuously. Thus we can explain that the pulse-like disturbance of the ground motion velocity occurs when the isochrones jumping intensity has nonzero value. We, however, think that further discussion with respect to the decision of rupture velocity is required. So we would like to study the dynamic rupture model in order to understand how to give the spatial distribution of rupture velocity in future works.

Contributors:

Imai, Ryuta

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

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