Seismic characterization of fracture compliance in the field using P - and S -wave sources
Seismic characterization of fracture compliance in the field using P - and S -wave sources
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使用纵波和横波源现场地震表征裂缝顺应性
DOI：
10.1093/gji/ggv395
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发表时间：
2015
影响因子：
2.8
通讯作者：
Foord G
中科院分区：
文献类型：
--
作者：
Foord G
使用纵波和横波源进行近地表地震现场实验，对英格兰西南部两个地点的裂隙石灰岩进行成像。我们测量了多个方位角上的纵波和横波地震速度以对准裂缝组，从而使我们能够确定这些裂缝产生的地震各向异性。对齐裂缝对地震各向异性的影响通常根据裂缝引入的附加柔量进行建模。因此，了解裂缝顺应性对于解释现场各向异性观测结果和裂缝对地震波传播影响的正演模拟至关重要。特别值得关注的是（1）骨折顺应性与骨折长度尺度的关系，以及（2）对骨折法向顺应性与切向顺应性之比的控制（Ω=ZN/ZT）。我们的实验设计使我们能够对两者进行成像，我们发现两个研究地点的Ω= 0.37 ± 0.06 和Ω= 0.75 ± 0.10，而切向柔量的绝对值范围从0.66 × 10−11 到5.0 × 10−11Pa−1m。
Near-surface seismic field experiments using bothP- andS-wave sources were carried out to image fractured limestones at two sites in southwest England. We measuredP- andS-wave seismic velocities at multiple azimuths to aligned fracture sets, allowing us to determine the seismic anisotropy generated by these fractures. The effect of aligned fractures on seismic anisotropy is commonly modelled in terms of the additional compliance introduced by the fractures. Therefore, an understanding of fracture compliance is crucial both in terms of interpreting observations of anisotropy in the field and in forward modelling the effects of fractures on seismic wave propagation. Of particular concern is (1) the scaling of fracture compliance with fracture length scale, and (2) the controls on the ratio of normal to tangential compliance of the fractures (Ω=ZN/ZT). Our experimental design allows us to image both, and we find thatΩ= 0.37 ± 0.06 andΩ= 0.75 ± 0.10 for our two study sites, while the absolute values of the tangential compliance range from 0.66 × 10−11to 5.0 × 10−11Pa−1m.