断層パッチのサイズ分布と不均質断層の震源スペクトル構造
―断層の不均質性とfmax―
1989 年 42 巻 4 号 p. 475-484
詳細
1989 年 42 巻 4 号 p. 475-484
A theoretical study is made on the earthquake source spectrum for heterogeneous faultings with self-similar fault patches. The source spectrum of this fractal fault patch model is not so simple as that of the standard ω square model. It shows a frequency dependence of ω0-ω-2-ω-δ-ω-2+γ/2-ω-2, where δ is about 1 and γ is the fractal dimension of self-similar fault patches. γ takes a value in between 0 and 2. The spectrum demonstrates three characteristic corner frequencies, where the spectral envelope changes its trend. They corresponds to the rupture times of whole fault length, maximum fault patch, and minimum fault patches. The first is corner frequency well-known in long-period seismology. The second is understood as patch corner frequency. The third would be the cut-off frequency of fmax in the acceleration spectra.
