Applicability of Strong Motion Prediction Recipe for Recent
Disastrous Earthquakes

at KSHSG4 (-250 m deep at Service Hole of the KKPP) using a standard model of the#Kojiro Irikura, Susumu Kurahashi (Aichi Institute of Technology), andKen Miyakoshi (Georesearch Institute)right middle of Fig. 1. We make a revised source model with 1.5 times stress drop of“recipe” are clearly underestimated compared with the observed ones as shown in thethe asperities, keeping the asperity areas constant. Another modification is that thestarting point of Asp2 is located at the center of the asperity as shown in the left ofWe have studied that ground motions from inland-crust earthquakes are wellFig.1, learning from the best-fit model of the earthquake. We find that the synthesized

simulated using a characterized source model with asperities in an entire rupture area.

motions for the revised model have almost the same level as the observed ones as

The characterized model is constructed based on the “recipe” we proposed. In thisshown by red lines in the right bottom of Fig. 1. This means that the “recipe” should be

study, applicability of the “recipe” has been examined by comparing observed groundmodified, considering regional characteristics of the fault parameters such as stressmotions with synthesized ones for recent disastrous earthquakes. We show a case of thedrop and rupture starting point of each asperity to make more reliable evaluation of2007 Chuetsu-oki (Mw 6.6) as one of examples. This earthquake occurred very close

ground motions.

to the Kasiwazaki-Kariwa Nuclear Power Plant. The surface motions there had the50

PGA of more than 1200 gals and even underground motions on one of the base-mats of

the hypocenter distribution (Earthquake Research Institute, 2008) in and around thesource region of this earthquake. Seismic moment is given from the scaling of the outer-50
-100

Asp1

-150
2050

Asp2
Asp1

Asp2

Area（km2）

77.7

38.3

Stressdrop(MPa)

21.2

21.2

AMP(cm/s)

km, respectively, based on the investigation of the active fault (Sugiyama, 2008) andNS VEL

0

the reactors locating five stories below the ground had the PGS of 680 gals.
Fault length L and width W as the outer fault parameters are given at 26 km and 22OBSSYN(standard model)
SYN（recised model）

KSHSG4

Revised Model

04050304050-50-100-15020fault parameters. The areas and stress drop of the asperities as the inner fault

30EW VELTIME(sec)parameters are given using the empirical relation, acceleration level versus seismicFig. 1. Left: Map showing the revised model for simulation. Right: Comparison

moment by Dan et al. (2001), following the “recipe” by the Earthquake Research

between the synthesized motions and observed records at KSHG4. In each panel, theCommittee in Japan (2007). Then, the characterized source model with two asperities

top is the observed, the middle is the synthesized for the standard model, and thewith large and small areas inside the rupture area is made. The area of the large

bottom is that for the revised model.

asperity has twice as large as that of the small one. The locations of those twoasperities are located as shown in the left of Fig. 1.Synthesized motions are calculated

Acknowledgements: We thank to Tokyo Electric Power Company (TEPCO) for

using the empirical Green’s function method (Irikura, 1986). The synthesized motions

providing strong ground motion data at the Kashiwazaki-Kariwa nuclear power plant.