微動アレイ探査における空間自己相関法の自己回帰モデルを用いた改良 [in Japanese] Modified Spatial Autocorrelation Method using Autoregressive Model for Estimating Underground Velocity Structure from Microtremor Array Observation [in Japanese]
Access this Article
Search this Article
Spatial autocorrelation method(SAC)is an efective analysis for estimating underground S-wave velocity structure from microtremor phase velocity dispersion relation because it has larger detectable range of microtremor wavelength than frequency-wavenumber analysis. However, phase velocities estimated by conventional SAC methods such as band-pass filtered method or Fast Fourier Transform method were not precise if suitable band width was not selected for analysis. We proposed a new technique for SAC using autoregressive model which estimated spectra with high resolution becaus the best fitting model can be selected using AIC. We apply the new method to calculate phase velocities of microtremors which were observed at a ground of Morioka Technical High School with arrays. As a result, phase velocities calculated by the new method were continous with frequency although those calculated by the conventional methods were scattered. This indicates that SAC functions calcdated by the new method are estimated better than those by conventional SAC methods.
- Geophysical exploration
Geophysical exploration 51(1), 70-76, 1998-02-01