13:45 〜 14:00
[S07-9-02] Validating a source model for the 2011 Tohoku Earthquake using a dense strong-motion array
After the 2011 Tohoku, Japan, Earthquake, the importance of reliable predictions of strong ground motions for mega-thrust earthquakes has become more widely recognized than ever. For this purpose, it is essential to validate source models and simulation methods using the strong-motion data of the Tohoku earthquake.
From engineering point of view, one of the most striking features of strong ground motions of the Tohoku earthquake was the generation of pulses; strong ground motions in the frequency range from 0.2 to 1 Hz observed at stiff stations along the coast of Miyagi through Ibaraki were characterized by distinctive pulses (Nozu et al., 2012). The importance of the pulses is that they appeared in the frequency range relevant to structural damage.
A source model called the "SPGA (Strong-motion Pulse Generation Area) model" was developed to explain strong ground motions from the Tohoku earthquake including the pulse (Nozu et al., 2012). The source model involved nine subevents with relatively small size (on the order of several kilometers), located off the coast of Miyagi through Ibaraki. This source model satisfactorily reproduced strong ground motions of the earthquake along the coast of Miyagi through Ibaraki including the pulses. In contrast, source models with larger subevents (SMGAs) with a size of tens of kilometers failed to reproduce those pulses.
Although the SPGA model was already validated using strong motion records along the coast, it is necessary to further investigate the reliability of the source model especially by using records from dense strong-motion arrays such as the Small-Titan (Kamiyama et al., 1999). In this study, the SPGA model will be applied to simulate strong ground motions at 17 Small-Titan stations and its performance will be discussed.
From engineering point of view, one of the most striking features of strong ground motions of the Tohoku earthquake was the generation of pulses; strong ground motions in the frequency range from 0.2 to 1 Hz observed at stiff stations along the coast of Miyagi through Ibaraki were characterized by distinctive pulses (Nozu et al., 2012). The importance of the pulses is that they appeared in the frequency range relevant to structural damage.
A source model called the "SPGA (Strong-motion Pulse Generation Area) model" was developed to explain strong ground motions from the Tohoku earthquake including the pulse (Nozu et al., 2012). The source model involved nine subevents with relatively small size (on the order of several kilometers), located off the coast of Miyagi through Ibaraki. This source model satisfactorily reproduced strong ground motions of the earthquake along the coast of Miyagi through Ibaraki including the pulses. In contrast, source models with larger subevents (SMGAs) with a size of tens of kilometers failed to reproduce those pulses.
Although the SPGA model was already validated using strong motion records along the coast, it is necessary to further investigate the reliability of the source model especially by using records from dense strong-motion arrays such as the Small-Titan (Kamiyama et al., 1999). In this study, the SPGA model will be applied to simulate strong ground motions at 17 Small-Titan stations and its performance will be discussed.