| 講演要旨(和文) | | 既往の研究より市区町村内といった狭い範囲においても、表層地盤の違いなどによって揺れやすさが異なる事が知られている。そこで、複雑な地形や地下構造を有する神奈川県逗子市内において超高密度地震観測を行った。まず、市内に 61地点の地震計を設置し6月から12月までの半年間、臨時地震観測を行なった。そのうち59地点と15地震を解析の対象とした。解析はまず、得られた観測データから、3成分合成最大速度と各成分のフーリエスペクトルを求めた。次に、最も揺れの小さかった観測点を露頭基盤(基準点)と考え、各観測点と基準点との比を取ることで揺れやすさを評価し、既往の災害ハザード情報との比較も行った。以上の解析の結果、既往のハザード情報より狭い範囲での揺れやすさの違いが見られ、最大速度比に関しては、地震ごとに揺れやすさの分布が異なること、フーリエスペクトル比に関しては、地震による形状の変化はないことが分かった。 |
|
|
| | 講演要旨(英文) | | In a narrow range, such as within the city, it has been found that the sway of ground is difficult due to differences of surface subsoil in history. We make an high-density seismic observation in Zushi city with complex terrain and underground structure. From these things, we set up 61 seismographs there and observed during about a half year from June. Among them , 59 points and 15 earthquake was the subject of analysis. First, from the obtained observation data, we determined the three-component synthetic maximum speed and the Fourier spectrum of each component. Then, we think the most sway of small was the observation point as outcrop foundation, asked the ratio of each observation point to that point and evaluated the shaking ease. In addition, we compared with the disaster hazard information of history. As a result of the above analysis, it can be seen that the difference in a more narrow range than the range of hazard information of history. with regard to the maximum speed ratio, the distribution of shaking ease every earthquake was different, with Fourier spectrum ratio, it did not change shape by earthquake. |
|
|
|
| |
|