논문 상세보기
The slip-weakening model developed by Ohnaka and Yamashita is extended over the breakdown zone by equating the scaling relationships for the breakdown zone and the whole rupture area. For the extension, the study uses the relationship between rupture velocity and radiation efficiency, which was derived in the theory of linear elastic fracture mechanics, and the definition of fmax given in the specific barrier model proposed by Papageorgiou and Aki. The results clearly show that the extended scaling relationship is governed by the ratio of rupture velocity to S wave velocity, and the velocity ratio can be determined by the ratio of characteristic frequencies of a Fourier amplitude spectrum, which are corner frequency, fc, and source-controlled cut-off frequency, fmax, or vice versa. The derived relationship is tested by using the characteristic frequencies extracted from previous studies of more than 130 shallow crustal events (focal depth less than 25 km, MW 3.0~7.5) that occurred in Japan. Under the assumption of a dynamic similarity, the rupture velocity estimated from fmax/fc and the modified integral timescale give quite similar scale-dependence of the rupture area to that given by Kanamori and Anderson. Also, the results for large earthquakes show good agreement to the values from a kinematic inversion in previous studies. The test results also indicate the unavailability of the spectral self-similarity proposed by Aki because of the scale-dependent rupture velocity and the rupture velocity-dependent fmax/fc; however, the results do support the local similarity asserted by Ohnaka. It is also remarkable that the relationship between the rupture velocity and fmax/fc is quite similar to Kolmogorov’s hypothesis on a similarity in the theory of isotropic turbulence.
1. 서 론
2. EBM과 SWM의 확장
2.1 기본 정의와 동적 유사성
2.2 Eshelby-Brune의 모델 (EBM)과 자기 유사성
2.3 Slip-Weakening 모델 (SWM)
2.4 SWM의 확장
3. fmax/fc의 Vr 의존성
3.1 지진파 방사 효율의 Vr 의존성
3.2 fmax/fc의 Vr 의존성
3.3 fmax/fc의 Vr 의존성과 Kolmogorov의 가설
3.4 일정한 Vr 과 fmax의 스케일 의존성의 문제점
4. Vr의 스케일 의존성과 단층 면적의 추정
5. 결 론
REFERENCES
