Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Oral

S (Solid Earth Sciences) » S-SS Seismology

[S-SS10] Seismic wave propagation: Theory and Application

Wed. May 23, 2018 1:45 PM - 3:15 PM A10 (Tokyo Bay Makuhari Hall)

convener:Kiwamu Nishida(Earthquake Research Institute, University of Tokyo), Kazuya Shiraishi(Japan Agency for Marine-Earth Science and Technology), Takao Nibe((株)地球科学総合研究所, 共同), Kaoru Sawazaki(National Research Institute for Earth Science and Disaster Resilience), Chairperson:Takemura Shunsuke(防災科研), Yabe Suguru(JAMSTEC)

1:45 PM - 2:00 PM

[SSS10-01] Wide Observation Range of Borehole Stress meter and Strain meter ,and Comparison among Long Period Observation Instruments

Hiroshi Ishii1, Yasuhiro Asai1, *Muneyoshi Furumoto1 (1.Tono Research Institute of Earthquake Science, Association for the Development of Earthquake Prediction)

Keywords:Borehole stressmeter, 2011Tohoku Eq.MW9.0 , Wide observation range, Comparison of records among long period observation instruments, Stress seismogram

Wide Observation Range of Borehole Stressmeter and Strainmeter, and Comparison of Wave Forms among Long Period Observation Instruments
During the Tohoku Earthquake (MW 9.0) on March 11, 2011, the long-period components recorded by most of the STS seismometers and velocity seismographs in Japan went off-scale and these instruments were not able to record large amplitudes. However, all of the borehole stress meters and strain meters developed for continuous observations at the Tono Research Institute of Earthquake Science (TRIES) were capable of recording the maximum amplitudes of the signals. In this study, we examined the observable ranges of the borehole stress and strain meters used for continuous observations. We found that the borehole stress meters have wide observable ranges (even for high-sensitivity components) and these instruments respond to the direct current (DC) components of frequency.

In addition, the borehole stress meters were able to observe stresses and strains in an earthquake with a wave amplitude several times as large as the Tohoku Earthquake without the signals going off-scale. Also it becomes clear that the stress and strain meters can record wave amplitude without the signals going off-scale even if the instruments are set up at coasts of Tohoku area near the hypocenter.

Next, we compared waveforms observed by STS1 seismometer, Guralp seismometer, servo velocity meter (Tokyo Sokusin CO.LTD) and our stress meter. It is found that three seismometers recorded similar wave forms. And after body wave arrival 4 instruments indicate similar wave forms even for stress meter.