DEVELOPMENT OF GEOPHYSICAL EXPLORATION SYSTEM BASED ON ARRAY OBSERVATION OF MICROTREMORS

基于微震阵列观测的地球物理勘探系统开发

基本信息

批准号：
06555169
负责人：
TOKIMATSU Kohji
金额：
$ 3.07万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06555169/
关键词：
Microtremors Array observation Surface waves Rayleigh waves Love waves Shear wave profile Amplification F-k spectrum analysis 地盤の増幅特性短周期微動地盤探査地盤災害地盤の固有周期逆解析

项目摘要

Field techniques and analyticalprocedures for geotechnical site characterization using microtremors have been presented in addition to their theoretical background. Microtremor measurements using arrays of sensors are conducted over a day at two sites fo explore the nature of microtremors. The F-k spectrum analysis of microtremor three-component motions provide phase velocity dispersion characteristics of vertical and horizontal motions. It is shown that :(1) The F-k spectrum analysis of the microtremor vertical components can provide dispersion characteristics of Ray leigh waves that are stationary over periods of a day, even if the source effects have a significant effect on microtremor ground motions.(2) The F-k spectrum analysis on microtremor horizontal motions appears capable of extracting one of the dominant surface waves, i.e., generally Love waves, even through microtremors propagate from various directions. If microtremors propagate from one direction, both Ray leigh and Love … More characteristics may be obtained.(3) The response factor, the medium response divided by the wavenumber of the squire root of wavenumber, is an efficient indicator to determine the prevailingmode of surface waves.(4) If the microtremor H/V spectrum of a site has a distinct peak and a distinct minima, the impedance ratio of the site is relatively high. The natural period could be equal to or slightly larger than the period of the H/V peak ; and may be twice the period of the H/V minimum.(5) If the microtremor H/V spectrum of a site has neither distinct maximum nor minimum, the impedance ratio of the site is low, e.g., soil site having Vs gradually increases with depth or rock site. The natural site period may not be determined from microtremor measurements at one station.To demonstrate the effectiveness of the proposed methods, array observation of measurements are conducted at two sites in Kobe city. Conventional microtremor measurements with only one station are also made at about 100 places. The shear structures in the Kobe area are estimated down to a depth of 2km. Effective stress response analysis is then made using the estimated soil profiles. The distribution of the estimated peak ground velocity and acceleration are consistent with that of the structural damage during the 1995 Hyogoken-Nanbu earthquake, suggesting that the proposed methods are effective. Less

除了其理论背景外，还提供了使用微生子的岩土部位表征的现场技术和分析程序。使用传感器阵列的微晶状体测量在一天的两个位置进行，以探索微生物的性质。微晶状体三成分运动的F-K频谱分析提供了垂直和水平运动的相速度分散特征。 It is shown that :(1) The F-k spectrum analysis of the microtremor vertical components can provide dispersion characteristics of Ray leigh waves that are stationary over periods of a day, even if the source effects have a significant effect on microtremor ground motions.(2) The F-k spectrum analysis on microtremor horizontal motions appears capable of extracting one of the dominant surface waves, i.e., generally Love waves, even through微晶状体从各个方向传播。如果微晶状体从一个方向传播，雷·利（Ray Leigh）和爱情都可以获得更多的特征。（3）响应因子，介质响应除以波数的乡绅根的波数，是一个有效的指标，是确定表面波的盛行模式。高的。自然周期可能等于或略大于H/V峰的周期。（5）如果位点的微晶状体h/v光谱既没有明显的最大也不是最小，则该位点的阻抗比较低，例如，土壤位点与深度或岩石位点逐渐增加。自然现场周期不可能通过一个站点的微晶体测量结果确定。为了证明所提出的方法的有效性，在科比市的两个地点进行了测量阵列观察。在大约100个位置，也只能使用一个站点进行常规的微晶体测量。估计，科比区域的剪切结构估计为2公里。然后使用估计的土壤谱进行有效的应力反应分析。估计的峰值地面速度和加速度的分布与1995年Hoogoken-Nanbu地震期间结构损伤的分布一致，这表明所提出的方法有效。较少的