| 講演要旨(和文) | | 平成23年東北地方太平洋沖地震と4月7日に発生したその余震について，両地震で大きな被害が発生した岩手県奥州市において高密度アンケート震度調査を行った．奥州市前沢区の計測震度は，本震，余震ともに震度6弱を観測した．アンケート震度調査には太田方式(1998)を利用した．奥州市の31校の小学校の全児童の家庭を対象に，両地震について7,284枚の調査票を配布した．本震では有効3,838枚,最大震度は7.29，最小震度は2.84，平均は5.45，余震では有効4,406枚，最大震度は7.19，最小震度は2.20，平均は4.83であった．本震と余震で同じ場所に位置するメッシュで震度を比較した結果，両地震のアンケート震度の相関は高いことが確認された．奥州市前沢区と江刺区では相対的に震度が大きいことがわかった．ただし，奥州市全体でアンケート震度と表層地盤増幅率の関係を調べたが相関はあまり高くなかった． |
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| | 講演要旨(英文) | | To clarify the vibration characteristics in Oshu City of Iwate Prefecture, where many houses were damaged by both the 2011 off the Pacific coast of Tohoku Earthquake and the aftershock occurred at April 7, 2011, the survey of seismic intensity was done using questionnaires for both the main shock and the aftershock. 7,284 questionnaires were distributed for parents of students of 31 elementary schools for both earthquakes. The seismic intensities for the main shock were ranging from 7.3 to 2.8, and the average was 5.5. The seismic intensities for the aftershock were ranging from 7.2 to 2.2, and the average was 4.8. The seismic intensities calculated from questionnaires were averaged for 1km or 250m square meshes in whole Oshu City. As a result, it was revealed that the seismic intensities in Maesawa Distruct and Esashi District of Oshu City ware large. The seismic intensities for the main shock had a good correlation with those for the aftershock. In whole Oshu city, however, the seismic intensities for the main shock did not have a good correlation with site amplifications. |
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