P10

Comparison between Physics- and Empirical-based Ground Motion Predictions for Hanaore Fault
in Kyoto Basin〇Thinzar Yadanar, Soichiro KUNO, Yuting CHOU, Fumiaki NAGASHIMA, Shinichi MATSUSHIMAIntroduction

we use 3D finite difference method for low frequency

In ground motion prediction, physics-based andwaveforms (<1.2Hz) and stochastic Green’s function

empirical-based

widelymethod for high frequency waveforms (>1.2Hz). we

implemented for different earthquake scenarios. The

performed the fourth-order spatial finite different

Physics-based approach involves source rupture

method (Levander, 1988) applying the discontinuous

process modeling and consideration of seismic wave

grid (Aoi and Fujiwara, 1999) on the Ground Motion

propagation, so that it requires detailed fault parameters

Simulator (GMS) (Aoi et al., 2004). We utilized theand subsurface structure. On the other hand, thestochastic Green’s function method (Dan and Sato,empirical-based approach utilizes ground motion

1998; Dan et al., 2000). Both software are provided bymodels based on regression of observed data tothe National Research Institute for Earth Science andcalculate the expectative ground motion of theDisaster Resilience (NIED). The waveforms obtained

earthquakes without taking account of detailed sourceby the two simulations were combined by applying therupture process and wave propagation.

matching filter (matching frequency of 0.85Hz, Fig. 1),

The aim of our research is to develop a novel approachand then the broadband ground motions on thefor probabilistic ground motion prediction byengineering bedrock were obtained (Fig. 2). For thecombining physics-based and empirical-based groundempirical-based approach, we used the ground motion

motion predictions. By comparing the average andmodel (Si and Midorikawa, 1999) to predict the grounduncertainties of the results from the two different

motion on the engineering bedrock (NIED, 2011). We

approaches, it can help to highlight the similarity andutilize the earthquake scenarios for the Hanaore fault

inconsistency between different approaches which canprovided by Japan Seismic Hazard Information System

help us to get the idea of what kind of uncertainty

and follow the recipe for ground motion prediction

should be considered depending on the site location. In

published by the Headquarters for Earthquake

this presentation, we will focus on the comparison of

Research Promotion for modeling of fault geometry.

approaches

have

been

physics-based and empirical-based ground motion
predictions results for Hanaore fault, a right lateral
strike-slip fault trending NNE-SSW direction, whichruns through the north and east part of Kyoto Basin.
Methodology
The purpose of this research is to understand thedifferences and the similarities of the resulted groundmotions on the engineering bedrock from the twodifferent approaches. For the physics-based approach,Fig 1. Matching filter applied in the hybrid method1physics-based and empirical-based approaches, we aim
to understand the average and uncertainty of the groundmotion from two approaches.
Summary
Our main goal is to integrate physics-based andempirical-based approaches to the probabilistic seismic
hazard analyses (PSHA) in consideration of theuncertainty which we can understand from the twodifferent approaches. To achieve this goal, we compare
the ground motion results in Kyoto Basin from physicsFig 2. Waveforms simulated by stochastic green’s

based and empirical-based approaches to know thefunction method (upper panel), 3D finite difference

variation of the ground motions related to source

method (middle panel) and Hybrid method (lowermechanism and site condition. By understanding of thepanel)ground motion variations depending on the source andDiscussion

site, we can perceive the uncertainty that should be

Ground motion at one station location depends not only

considered in PSHA to obtain more reliable groundon the mechanism of the fault but also on the subsurface

motion predictions. We will compare the groundstructure around the station. To get a certain groundmotion prediction results at 800 stations in Kyoto Basinmotion at that station, we should consider the detailed

by considering three earthquake scenarios of Hanaore

fault rupture process and also detailed subsurface

Fault.

structure of the area of interest. Ground Motion at thesites of interest may vary depending on the source

References

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directivity, rupture pattern and fault geometry), path

Method using discontinuous grids”. Bull. Seism. Soc

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area. For example, the station at the center of the basin

Dan, K. and T Sato (1998): Journal of Structural andand those at the edge of the basin also have some

Construction Engineering, No.509, 49-60.

variations in recorded ground motions because of site

Dan, K., et al. (2000): Journal of Structural andcharacteristics. Ground motion prediction by using

Construction Engineering, No.530, 53-62.

ground motion models (empirical-based) which is only

Fujiwara, H. et al. (2009). Technical Reports onconsider the magnitude and source to site distance canNational Seismic Hazard Maps for Japan, Technicallead to underestimated or overestimated ground motion

Note of the National Res. Inst. for Earth Science andresults as it does not consider detail source and site

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conditions.

Irikura, K. and Miyake, H. (2001): Journal ofIn our research, we calculate ground motions at 800

Geography, 110,849-875

stations with 1 km x 1 km grid inside Kyoto basin. By

Si, H. and Midorikawa, S. (1999): Journal of Structuralcomparing the simulated ground motion results fromand Construction Engineering. No 523, 63-70

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