Shear Velocity Model of Alaska Via Joint Inversion of Rayleigh Wave Ellipticity, Phase Velocities, and Receiver Functions Across the Alaska Transportable Array
Shear Velocity Model of Alaska Via Joint Inversion of Rayleigh Wave Ellipticity, Phase Velocities, and Receiver Functions Across the Alaska Transportable Array
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DOI：
10.1029/2019jb018582
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发表时间：
2020-02
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影响因子：
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通讯作者：
E. Berg;F. Lin;A. Allam;V. Schulte‐Pelkum;K. Ward;W. Shen
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作者：
E. Berg;F. Lin;A. Allam;V. Schulte‐Pelkum;K. Ward;W. Shen
通过部署 200 多个站的阿拉斯加可移动阵列，我们创建了阿拉斯加的 3D 断层扫描模型，其灵敏度范围从近地表（<1 公里）到上地幔（约 140 公里）。我们根据环境噪声和地震测量结果对瑞利波椭圆率和相速度进行马尔可夫链蒙特卡罗联合反演，并结合接收器函数来创建剪切波速度模型。我们还使用后续相速度反演来解析站间结构。通过将我们的结果与之前的断层扫描、地质学和地球物理研究进行比较，我们能够验证我们的发现，并将局部近地表研究与更深入的区域模型联系起来。具体来说，我们能够解析浅盆地，包括库珀河、库克湾、育空平原、尼纳纳和各种其他浅盆地。此外，我们还深入了解了上地幔楔、软流圈以及沿阿留申群岛和德纳利火山间隙的活动和非活动火山活动之间的相互作用。我们在布鲁克斯山脉下方和迪纳利断层以南的兰盖利亚复合地体中观察到较厚的地壳，而在阿拉斯加内陆的育空地区复合地体中观察到较薄的地壳。我们还获得了关于兰格尔火山场及其周围软流圈与雅库塔地体之间相互作用的新视角。
Through the Alaska Transportable Array deployment of over 200 stations, we create a 3‐D tomographic model of Alaska with sensitivity ranging from the near surface (<1 km) into the upper mantle (~140 km). We perform a Markov chain Monte Carlo joint inversion of Rayleigh wave ellipticity and phase velocities, from both ambient noise and earthquake measurements, along with receiver functions to create a shear wave velocity model. We also use a follow‐up phase velocity inversion to resolve interstation structure. By comparing our results to previous tomography, geology, and geophysical studies we are able to validate our findings and connect localized near‐surface studies with deeper, regional models. Specifically, we are able to resolve shallow basins, including the Copper River, Cook Inlet, Yukon Flats, Nenana, and a variety of other shallower basins. Additionally, we gain insight on the interaction between the upper mantle wedge, asthenosphere, and active and nonactive volcanism along the Aleutians and Denali volcanic gap, respectively. We observe thicker crust beneath the Brooks Range and south of the Denali fault within the Wrangellia Composite Terrane and thinner crust in the Yukon Composite Terrane in interior Alaska. We also gain new perspective on the Wrangell Volcanic Field and its interaction between surrounding asthenosphere and the Yakutat Terrane.