High-resolution lithospheric imaging with seismic interferometry
High-resolution lithospheric imaging with seismic interferometry
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DOI：
10.1111/j.1365-246x.2010.04724.x
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发表时间：
2010-10
影响因子：
2.8
通讯作者：
E. Ruigrok;X. Campman;D. Draganov;K. Wapenaar
中科院分区：
文献类型：
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作者：
E. Ruigrok;X. Campman;D. Draganov;K. Wapenaar
近年来，部署相对密集的地震台站阵列的情况有所增加。空间密集采样的全球和区域地震数据的可用性刺激了应用于远距离地震的转换波和散射波能量的工业式成像算法的采用，从而产生了相对高分辨率的下地壳和上地幔图像。我们使用地震干涉测量来从远距离地震的传输能量的尾波中提取反射响应。从理论上讲，用地震干涉法而不是传统的岩石圈成像方法中使用的转换来偏移反射时，可以获得更高分辨率的图像。此外，反射数据允许直接应用以前在勘探地震学中开发的算法。特别是，反射数据的可用性使我们能够使用标准的多通道数据处理方法从其中提取速度模型。然而，我们方法的成功主要取决于地震的有利分布。本文研究了地震分布和传播波场的复杂程度对干涉法反射响应质量的影响。我们的分析表明，如果(1)阵列与地震活动区近似对准，(2)使用不同的相位响应来收集足够的角度照明，以及(3)在处理过程中适当地考虑照明方向，则可以提取合理的反射响应。我们使用一个合成数据集来说明我们的分析，该数据集具有与2000-2001年拉勒米宽带实验期间记录的现场数据相似的照明和源侧混响特性。最后，我们将我们的方法应用于拉勒米数据，提取反射数据。我们从反射波中提取一个二维速度模型，并使用该模型来偏移数据。在最终的反射率图像上，我们观察到反射中的不连续。我们将这种不连续解释为夏延带，它是太古宙和元古界之间的缝合带。
In recent years, there has been an increase in the deployment of relatively dense arrays of seismic stations. The availability of spatially densely sampled global and regional seismic data has stimulated the adoption of industry-style imaging algorithms applied to converted- and scattered-wave energy from distant earthquakes, leading to relatively high-resolution images of the lower crust and upper mantle.We use seismic interferometry to extract reflection responses from the coda of transmitted energy from distant earthquakes. In theory, higher resolution images can be obtained when migrating reflections obtained with seismic interferometry rather than with conversions, traditionally used in lithospheric imaging methods. Moreover, reflection data allow the straightforward application of algorithms previously developed in exploration seismology. In particular, the availability of reflection data allows us to extract from it a velocity model using standard multichannel data-processing methods. However, the success of our approach relies mainly on a favourable distribution of earthquakes. In this paper, we investigate how the quality of the reflection response obtained with interferometry is influenced by the distribution of earthquakes and the complexity of the transmitted wavefields. Our analysis shows that a reasonable reflection response could be extracted if (1) the array is approximately aligned with an active zone of earthquakes, (2) different phase responses are used to gather adequate angular illumination of the array and (3) the illumination directions are properly accounted for during processing. We illustrate our analysis using a synthetic data set with similar illumination and source-side reverberation characteristics as field data recorded during the 2000–2001 Laramie broad-band experiment. Finally, we apply our method to the Laramie data, retrieving reflection data. We extract a 2-D velocity model from the reflections and use this model to migrate the data. On the final reflectivity image, we observe a discontinuity in the reflections. We interpret this discontinuity as the Cheyenne Belt, a suture zone between Archean and Proterozoic terranes.