Quantification and Modelling of Anomalous Surface Wave Refraction

已经获得了在热成熟的西太平洋中传播的周期为10-100秒的Rayleigh波发生明显折射的直接证据。对瑞利艾里相位和早尾波和晚尾波的频率相关偏振态的测量表明，折射波具有带状谱结构的特征，在每个带中具有不同的信号偏振。这种带状结构可能对应于类似带状的频率依赖性的基本模式的不均匀性的软流圈，岩石圈，地壳，和扰动的水深的敏感性。如果是这样的话，测量诸如后方位角和垂直分量与准纵向分量之间的相位差的量的频率依赖性可以提供用于解析地壳、盖层和低速带中的非均匀性和可能的各向异性的分布的判别式。

Direct evidence has been obtained for significant refraction of Rayleigh waves of periods 10-100 sec propagating in the thermally mature western Pacific. Measurements of the frequency- dependent polarization states of Rayleigh Airy phases and early and late coda indicate that the refracted waves are characterized by a banded spectral structure, with different signal polarizations in each band. This banded structure may correspond to the similarly banded frequency dependence of the sensitivity of the fundamental mode to heterogeneity in the asthenosphere, lithosphere, crust, and perturbations to the bathymety. If so, measurement of the frequency dependence of such quantitites as back azimuth and the phase difference between vertical and quasi- longitudinal components may provide discriminants for resolving the distribution of heterogeneity, and possible anisotropy, in the crust, lid, and low-velocity zone.