レーザー干渉計による地面振動の測定 II
異常振動の検知
1980 年 49 巻 12 号 p. 1185-1191
詳細
1980 年 49 巻 12 号 p. 1185-1191
The microvibration of the ground was measured by the 50 meter vacuum interferometer which was installed in the underground tunnel in the Nagatsuta Campus of the Tokyo Institute of Technology. There are often anomalous vibrations caused by cars passing on a near road for example. We propose a new method to detect and distinguish such anomalous vibrations. The signal which represents the vibration of the ground is put into a prediction error filter which is made from the normal part of the stignal. If there are any anomalous vibrations, its output, namely prediction error, becomes greater, and we can easily recognize its existence. This method is very sensitive and its characteristics is clerrly revealed by investigating the power spectrum and the frequency histograms of the signal.
