Joint inversion of teleseismic and ambient noise Rayleigh waves for phase velocity maps, an application to Iceland
Joint inversion of teleseismic and ambient noise Rayleigh waves for phase velocity maps, an application to Iceland
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DOI：
10.1002/2016jb012934
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发表时间：
2016-08
期刊：
影响因子：
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通讯作者：
N. Harmon;C. Rychert
中科院分区：
文献类型：
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作者：
N. Harmon;C. Rychert
本文提出了一种利用18 ~ 50 s周期的瑞利面波资料和环境噪声资料联合反演相速度图的方法。我们采用双平面波方法对地震数据进行了调整，以包括环境噪声相位数据。我们应用该方法从冰岛的ICEMELT和HOTSPOT阵列的数据。棋盘格测试表明，联合反演提高了相速度模型恢复的方法，使用数据集独立，特别是在18秒的周期。环境噪声数据的增加也扩展到较浅的深度和较短的周期相比，以前的冰岛下的ECOMETERICAL结果的分辨率。我们表明，有显着的差异，在相速度地图的联合方法相比，其他方法，例如，只使用微重力数据，只使用环境噪声数据，或两者的平均值。相速度的差异反过来影响所得到的剪切速度模型。联合反演的优点是它产生同时满足两个数据集的单相速度图。我们的相速度图显示了从18-25 s时期冰岛主要火山中心下方的低速中心（主要是地壳深度）到低速区域的过渡，该区域追踪了从南部Reykjanes Ridge到北部Kolbeinsey Ridge的裂谷带，在29-50 s时期，更大的深度。这些结果与以前的研究是一致的，虽然有一个扩展和改进的区域的分辨率，进一步延伸到大西洋和北冰洋。
We present a method for joint inversion of teleseismic and ambient noise Rayleigh wave data for phase velocity maps from 18 to 50 s period. We adapt the two‐plane wave method for teleseismic data to include ambient noise phase data. We apply the method to data from Iceland's ICEMELT and HOTSPOT arrays. Checkerboard tests show that the joint inversion improves phase velocity model recovery over methods that use the data sets independently, particularly at 18 s period. The addition of ambient noise data also extends resolution to shallower depths and shorter periods in comparison to previous teleseismic results beneath Iceland. We show there are significant differences in the phase velocity maps from the joint approach in comparison to other approaches, for instance, using only teleseismic data, only ambient noise data, or the mean of the two. The difference in phase velocities in turn affects the resulting shear velocity models. The advantage of the joint inversion is that it produces a single phase velocity map that satisfies both data sets simultaneously. Our phase velocity maps show a transition from low velocities centered beneath the main volcanic centers in Iceland at 18–25 s period, primarily crustal depths, to a low‐velocity region that traces the rift zones from the Reykjanes Ridge in the south to the Kolbeinsey Ridge in the north at 29–50 s period, greater depths. These results are consistent with previous studies, although with an extended and improved region of resolution, which extends further into the Atlantic and Arctic Ocean.