Traveltime tomographic inversion with simultaneous static corrections — Well worth the effort
Traveltime tomographic inversion with simultaneous static corrections — Well worth the effort
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DOI：
10.1190/1.3240931
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发表时间：
2009-12
期刊：
影响因子：
3.3
通讯作者：
A. Tryggvason;C. Schmelzbach;C. Juhlin
中科院分区：
文献类型：
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作者：
A. Tryggvason;C. Schmelzbach;C. Juhlin
我们已经开发了一个初至旅行时反演方案，联合解决地震速度和源和接收器的静态时间项。包括静态时间项，以补偿由近地表低速层引入的变化的时间延迟，该低速层太薄而不能通过层析成像来解决。在一个真实的数据集上的结果表明，层析成像静时项的值和分布与使用标准折射静校正软件计算的折射静校正非常相似，该数据集由在结晶环境中的地震反射2D/3D实验中拾取的初至时间组成。当应用于3D地震反射数据时，与使用标准折射静态软件校正的图像相比，层析成像静态时间项产生类似或更相干的地震反射图像。此外，该方法提供了一个更详细的模型，近地表基岩速度比标准软件时，静态时间项包括在反演。该模型中的低速带与其他地质和地球物理数据相关，这表明我们的方法产生了可靠的模型。除了在地震反射成像中通常需要的静校正之外，在走时层析成像中也需要静校正以获得地下的高保真速度图像。
We have developed a first-arrival traveltime inversion scheme that jointly solves for seismic velocities and source and receiver static-time terms. The static-time terms are included to compensate for varying time delays introduced by the near-surface low-velocity layer that is too thin to be resolved by tomography. Results on a real data set consisting of picked first-arrival times from a seismic-reflection 2D/3D experiment in a crystalline environment show that the tomography static-time terms are very similar in values and distribution to refraction-static corrections computed using standard refraction-statics software. When applied to 3D seismic-reflection data, tomography static-time terms produce similar or more coherent seismic-reflection images compared to the images using corrections from standard refraction-static software. Furthermore, the method provides a much more detailed model of the near-surface bedrock velocity than standard software when the static-time terms are included in the inversion. Low-velocity zones in this model correlate with other geologic and geophysical data, suggesting that our method results in a reliable model. In addition to generally being required in seismic-reflection imaging, static corrections are also necessary in traveltime tomography to obtain high-fidelity velocity images of the subsurface.