地震記録の特性と常時微動観測の比較

本研究は，常時微動観測を地震時応答解析の評価法として利用しようと考え，検討した結果をまと
めたものである．
常時微動観測の妥当性については，解析手法の1つであるH/Vスペクトル比を強震記録に対して求め，
解析結果を比較し，検討した．まず，徳島県内のK-NET観測地点5地点を対象に強震記録解析を行い，
地盤震動特性を求めた．次に同一地点において常時微動観測を実施し，地盤震動特性を求めた．そし
て，それぞれを比較検討した結果，両者に整合性があることを見出した．このことから，常時微動観
測が地震時応答解析の評価法として利用可能であることを検証した．

This paper presents a study on accuracy verification of microtemor measurement technique itself and possibility to be used as a
verification index of dynamic analysis, because no verification system on dynamic analyses is prepared yet, though it may be not
recognized.
As the first step, microtemor measurement technique was verified using indexes of H/V spectrum, here H stands for horizontal
acceleration observed, and V stands for vertical acceleration observed. In order to compare the ratio from data observed by the
microtemor adjacent a measurement house of K-Net in Tokushima prefecture for strong motion seismograph to that observed by the
K-Net system (accuracy of strong motion seismograph is proved; Over 2G of magnitude of acceleration is recorded), microtemor
were observed near measurement houses of K-Net. As predominant period of ground and amplification ratio are found from a H/V
spectrum diagram, index parameters of predominant period and amplification ratio are compared between data obtained by the
microtemor and records of strong motion. Sufficient accurate coincidence of indexes between two data is found. This result
concludes that the microtemor measurement technique can be used to obtain dynamic indexes instead of installation of strong
motion seismograph, as ground dynamic indexes obtained by the microtemor is assured to observe them with the same accuracy as
that observed by a strong motion seismograph.