抄録
We found low frequency signals which lasted for a few minutes to more than 10 min on long term visible records of Okuyama (OKY) station near Mt. Fuji (Fig. 1). The low frequency feature of these signals invokes teleseismic signals. However, these signals attenuate differently from teleseismic signals, and the corresponding signals are detected at other stations in Fig. 2 only when signals observed at OKY are fairly large. Waveforms as a whole are also quite different from teleseismic ones. Since these signals were identified more clearly in the seismograms of Fuji station on the mountain side of Mt. Fuji, sources of these signals are assumed to be near Mt. Fuji.
These signals contain P and S waves (Fig. 3), and are different from signals from artificial shots. S waves are identified clearly on traces of the horizontal component, while they are not identified clearly on the vertical component. It appears that each series of the low-frequency signals consists of many micro-earth-quakes which occurred in succession. The magnitudes estimated from the total duration time of each micro-earthquake are one or smaller.
