| 講演要旨(和文) | | 震源過程やS波偏向異方性の研究などでは，地震計の正確な方位情報が不可欠である．また，地表と地中の地震計の地震記録を用いた地盤応答解析などでも，2台の地震計の設置方位を考慮する必要がある．地中埋設地震計の方位を準リアルタイムで推定する方法を開発し，現地実証試験を行った．ボーリング孔底に設置されている地震計の孔口付近に地表地震計を設置し，地表地震計と地中地震計の微動波形の長周期成分を利用して相対的な方位を推定した．地表地震計の設置方位を0度，10度，20度の3段階に変えて，地中地震計との方位のずれを推定し，所定の値が得られることを確認した．地中地震計の方位が大きくずれていた場合には，開発した方法を用いて方位を確認しながら，再調整を行うことができた．開発した方法は，現場で即座に地中地震計の方位を推定できることから，地中地震計の設置に有用であると考えられる． |
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| | 講演要旨(英文) | | In studies such as the source mechanism and S-wave polarization anisotropy, it is essential that accurate azimuth information of the seismograph. Also, it is necessary to consider the installation azimuth of two seismographs as for the site response analysis based on seismic records of a surface and an underground seismograph. We developed a simple method to estimate the orientation of an underground seismograph. A relative azimuth was presumed by setting up the surface seismograph near the pithead of the underground seismograph, and using the long-period component of surface and underground micro-tremors. It was confirmed to change the installation azimuth of the surface seismograph into three stages (0 degrees, 10 degrees, and 20 degrees), to presume the gap of the azimuth with an underground seismograph, and to obtain a prescribed value. When an underground seismograph rotated greatly, it was possible to readjust by confirming the azimuth by using the developed method. Because the azimuth of an underground seismograph can be immediately presumed on the site, it is thought that the developed method is useful for the installation of an underground seismograph. |
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