| 講演要旨(和文) | | 平成23年東北地方太平洋沖地震および4月7日に発生した余震により岩手県一関市では多数の住宅等の被害が発生した．一関市において市域の面的な揺れを明らかにするために本震と4月7日の余震の超高密度アンケート調査を実施した．一関市西部の赤荻地区では震度6強や震度7と大きいことがわかった．地域ごとの震度差異の原因を調べるために1点3成分常時微動観測を計89ヶ所実施し,卓越周波数,平均rms振幅等の振動特性を解析した．赤荻地区ではH/Vピーク・卓越周波数が大きい値となり，山目町，山ノ目地区では小さい値となることがわかった．平均rms振幅より揺れの大きさを比較すると，山目町地区と山ノ目地区北部はバンドパスフィルター2〜4Hzで，赤荻地区東部は6〜10Hzで振幅分布が明瞭となった．赤荻地区は高周波数帯で地盤振動増幅率が大きくなり，山ノ目，山目町地区では，低周波数帯で増幅率が大きくなると示唆された． |
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| | 講演要旨(英文) | | To clarify the vibration characteristics in ichinoseki City of Iwate Prefecture, the survey of seismic intensity was done using questionnaires for both the 2011 off the Pacific coast of Tohoku Earthquake and the aftershock occurred at April 7, 2011. However, in the area many houses were damaged by a main shoch and aftershock on April 7. In the Akaogi area located in western Ichinoseki, it turned out1111, that it is large. And, microtremor observations were done at 89 points where seismic intensity were estimated, using a three-component seismometer. Averaged amplitudes, predominant periods and H/V spectra of observed microtremors were examined.In the Akaogi area, it turned out that a H/V peak and excellence frequency serve as a large value, and it becomes a value small in Yamamemachi and the Yamanome area. It is thought that a ground shaking amplification factor becomes large with a high-frequency belt, and, as for a Akaogi area, an amplification factor becomes large with a low frequency belt in Yamanome and a Yamamemachi area. |
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