6:15 PM - 7:30 PM
[SCG62-P02] Observation of the deep low-frequency earthquakes using deep borehole-seismograph network. Activity in Tokai area
Keywords:deep low-frequency earthquakes, deep borehole-seismograph network, array observation, semblance analysis
We applied the deep borehole-seismograph network and the high density network of seismic stations of TRIES in Tono region to the second 3D array. We called it Tono Juji array. Tono Juji array was constituted by two borehole stations of 1000 m depth, three borehole stations of 500 m depth and twelve shallow stations. Seismic wave data observed by acceleration seismographs were converted velocity data. All of the seismic wave data were unified to sample rate of 100Hz and filtered through a 2 to 10 Hz band pass filter. We selected a LFE with the maximum magnitude (M=0.6) among the 209 events from the JMA earthquake catalog and named it LFE108. The origin time of LFE108 was 2014/9/1, 15h26m40.77s. We found a slight signal of P wave of LFE108 in vertical component of each station. And we also found a slightly clear signal of S wave in horizontal component of each station. We could not find large difference in clear or unclear of the signals between borehole stations and shallow stations. It means that the cause of unclear LFE signals mainly depends on not ground noise but overlapping of P, S and Coda waves of many successive LFEs.
Acknowledgements: We thank to Japan Meteorological Agency (JMA) and National Research Institute for Earth Science and Disaster Prevention (NIED).