| Popis: |
We investigated the occurrence nature and spectral characteristics of the deep low frequency (DLF) earthquakes beneath Yakedake volcano, central Japan. The DLF earthquakes of Yakedake volcano locate mainly in the depth range from 20 to 40 km. Calculation of the recurrence rate of the DLF earthquakes for 10 minutes shows that the DLF events shallower than the boundary separating at 25 or 30 km tend to occur more successively than those deeper than the boundary depth. The ν-values of the DLF events also indicate the successive occurrence of the shallower events.The spectral analyses show the spectral peaks appear primarily in the frequency range 0.7 to 2 Hz. The spectral peaks are separated into one to four groups depending on the stations and components of the seismographs. Among them, the most prominent peaks are located around 1 Hz. These characteristics of occurrence nature and spectra of the DLF earthquakes are important information in considering source process of the DLF earthquakes. |
