Receiver Function Seismology
Receiver Function Seismology
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接收函数地震学
DOI：
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发表时间：
2019
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通讯作者：
L. Vinnik
中科院分区：
文献类型：
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作者：
L. Vinnik
本文简要地评述了接收函数技术的应用结果。在地幔过渡带，主要地震边界的地形进行了评价，分辨率约3公里的深度和横向分辨率约200公里。主边界深度变化幅度最大，达数十公里。热点地区的地幔过渡区变薄，温度分别升高约100°C。在若干区域，在地幔过渡带中发现了两个低速层：一个在410公里地震不连续面的正上方，另一个在450至500公里的深度。第一层的成因与地幔柱在橄榄石-华兹斯利岩相变过程中的脱水有关。第二层底部S波速度的增加可以解释所谓的520公里边界的观测结果。研究地壳上地幔结构的传统方法是利用面波。当使用P波和S波接收器功能的组合时，接收器功能可以在相同深度处提供更高的分辨率。这种类型的结果是在芬诺斯坎迪亚、卡普瓦尔克拉通、印度地盾、天山中部、贝加尔裂谷带、亚速尔群岛、佛得角群岛和西地中海获得的。S-接收器函数用于研究月球地壳。联合反演的P-和S-接收器功能提供了强大的估计参数的地震边界，包括弱不连续面，如岩石圈软流层界面的岩石圈。由接收函数确定的参数包括纵横波速度比。在少数区域，观察到下地壳的速度比非常高（>2.0），这可能表明存在具有高孔隙压力的流体。接收器函数允许估计作为深度的函数的方位各向异性的参数。参数随深度的变化使得区分与现代变形相关的活动各向异性和冻结各向异性（过去构造作用的影响）成为可能。
The results of application of the receiver function technique are briefly reviewed. In the mantle transition zone, the topography of the main seismic boundaries is evaluated with a resolution of about 3 km in depth and a lateral resolution of about 200 km. The variations of the depth of the main boundaries have the maximal amplitude reaching tens of kilometers. Thinning of the mantle transition zone in the hot spots and the respective increase in temperature by ~100°C is established. In several regions, two low-velocity layers are revealed in the mantle transition zone: one directly above the 410-km seismic discontinuity and another at a depth of 450 to 500 km. The origin of the first layer is associated with dehydration in the mantle plumes in the process of the olivine–wadsleyite phase transformation. The increase in the velocity of S-waves in the base of the second layer may explain the observations of the so-called 520-km boundary. The traditional approach to the studies of the structure of the crust and upper mantle is based on using the surface waves. Receiver functions can provide higher resolution at the same depths when a combination of P- and S-wave receiver functions is used. This type of results was obtained for Fennoscandia, Kaapvaal craton, Indian shield, Central Tien Shan, Baikal rift zone, the Azores, Cape Verde Islands, and the western Mediterranean. S-receiver functions were used in the study of the lunar crust. The joint inversion of P- and S-receiver functions provides robust estimates of the parameters of the seismic boundaries, including weak discontinuities such as the lithosphere–asthenosphere interface of cratons. The parameters determined from receiver functions include the P-wave to S-wave velocity ratio. In a few regions, a very high (>2.0) velocity ratio is observed in the lower crust that may indicate the presence of a fluid with a high pore pressure. Receiver functions allow estimating the parameters of the azimuthal anisotropy as a function of depth. The change of the parameters with depth makes it possible to distinguish the active anisotropy associated with recent deformations from the frozen anisotropy—the effect of the past tectonic processes.