Extrapolation of Irregular Subsurface Structures Using the Horizontal-to-Vertical Spectral Ratio of Long-Period Microtremors
Extrapolation of Irregular Subsurface Structures Using the Horizontal-to-Vertical Spectral Ratio of Long-Period Microtremors
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DOI：
10.1785/0120020137
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发表时间：
2003-04
影响因子：
3
通讯作者：
H. Uebayashi
中科院分区：
文献类型：
--
作者：
H. Uebayashi
沉积盆地地下三维构造建模的关键问题之一是对由反射和折射测量建立的二维模型进行外推和/或插值。使用微震动水平与垂直（H/V）频谱比，允许简单和快速的微震动测量，可能适合于此目的。研究了长周期微震H/V谱比作为三维盆地构造建模外推工具的有效性和实用性。在大阪盆地北部的51个台站进行了三分量微震观测，该盆地包含了该盆地最复杂的地质构造。微震H/V谱比在1到5秒范围内测量。为了重现这些观测结果，开发了三个二维有限元模型，这些模型考虑了从地震反射研究、微震阵列研究和深钻数据推断出的地下结构的不规则形状。结合二维模型得到的三维模型与该地区地表地质、活动断层位置等地质信息一致。此外，与重力法相比，该三维模型更为精细，分辨率也更高。因此，微震H/V谱比为三维盆地构造建模提供了一种有用的外推和插值技术。
One of the key problems in modeling the 3D subsurface structure of sedimentary basins is extrapolation and/or interpolation from 2D models constructed from reflection and refraction surveys. The use of microtremor horizontal-to-vertical (H/V) spectral ratios, allowing simple and quick microtremor measurements, may be suitable for this purpose. The validity and usefulness of long-period microtremor H/V spectral ratios are investigated as a possible tool for extrapolation in 3D basin structure modeling. Three-component microtremor observations were conducted at 51 stations in the northern section of the Osaka basin, which encompasses the most complex geological structures in the basin. The microtremor H/V spectral ratios were measured in the range 1 to 5 sec. To reproduce these observations, three 2D finite-element models have been developed that account for the irregular shape of subsurface structures deduced from seismic reflection studies, microtremor array studies, and deep-drilling data. The 3D model obtained by combining the 2D models is consistent with geological information for the area, such as surface geology and the location of active faults. Furthermore, compared with the basement structure derived from the gravity prospecting, this 3D model is more detailed and offers higher resolution than the gravitational method. Therefore, the microtremor H/V spectral ratio represents a useful technique of extrapolation and interpolation for modeling 3D basin structures.