Aftershock observation of the 1995 Hyogo-ken Nanbu earthquake in Awaji Island: strong motion and broad band observation

T. Okumura, H. Takenaka, S. Suzuki, T. Sasatani, M. Furumura, S. Saito, T. Matsushima, T. Furumura

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Abstract

The 1995 Hyogo-ken Nanbu earthquake occurred on January 17 1995. The maximum seismic intensity was seven in Kobe city and a part of Awaji island. The aftershocks were observed at three stations in Awaji island using three strong-motion seismometers and a broad-band seismometer from January 19 to April 4. During this period, 89 events were oberved. In these events, nine events were observed at all of the three stations. Among the nine events, three events were analysed using integration of velocity in the time domain and amplitude spectrum of S-wave for 5 seconds. Amplitude spectral ratios of two events occurring in Kobe side for 20 seconds from P-wave arrival, for 20 seconds from S-wave arrival, and S-wave part for 5 seconds were also analysed. Those amplitude spectra showed predominant frequency around 1-4 Hz for IWY and ABK stations, but TSM predominant frequency around 4-7 Hz. The spectral ratio shows 3-10 times amplification, around 1-2 Hz and 4-7 Hz for TSM/IWY, and around 0.9-2 Hz and 4-7 Hz for ABK/IWY. For TSM/IWY, 2-5 times attenuation was observed around 2-3 Hz.

Original languageEnglish
Pages (from-to)103-123
Number of pages21
JournalScience Reports - Kyushu University, Department of Geology
Volume19
Issue number1
Publication statusPublished - Dec 1 1995

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All Science Journal Classification (ASJC) codes

  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

Cite this

Okumura, T., Takenaka, H., Suzuki, S., Sasatani, T., Furumura, M., Saito, S., ... Furumura, T. (1995). Aftershock observation of the 1995 Hyogo-ken Nanbu earthquake in Awaji Island: strong motion and broad band observation. Science Reports - Kyushu University, Department of Geology, 19(1), 103-123.