Lg-wave attenuation in the Australian crust
Lg-wave attenuation in the Australian crust
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澳大利亚地壳中的 LG 波衰减
DOI：
10.1016/j.tecto.2017.08.022
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发表时间：
2017
期刊：
影响因子：
2.9
通讯作者：
Lian-Feng Zhao
中科院分区：
文献类型：
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作者：
Zhi Wei;Brian L.N. Kennett;Lian-Feng Zhao
我们估计的LG波质量因子（Q）在整个澳大利亚大陆的垂直分量LG波形。进行层析反演以构建0.05和10.0 Hz之间的58个频率的Lg衰减模型。对于0.5-2.0 Hz频带，可用的空间分辨率约为1.5° × 1.5°。在1.0Hz处，整个岛屿大陆的Lg波Q值在50 ~ 1250之间变化，平均值为850。Lg波Q图像中显着的区域变化与澳大利亚的许多地质特征和边界密切相关。澳大利亚西部、北方和南部的火山岩通常具有较高的Q值（700-1250），而澳大利亚东部的火山区、沉积盆地和造山带的特征是衰减增加（较低的Q值，50-650）。我们确定了频率依赖的Q的Lg波的不同块在澳大利亚，并发现频率依赖的Q是比传统的单一的幂律表示复杂得多。当与假设的几何传播关系相结合时，Lg Q地图提供了一种新的方式来评估任何事件位置的潜在地面运动。
We estimate the Lg-wave quality factor (Q) across the Australian continent from vertical-component Lg waveforms. A tomographic inversion is performed to construct an Lg attenuation model for 58 frequencies between 0.05 and 10.0 Hz. The available spatial resolution is approximately 1.5° × 1.5° for the 0.5–2.0 Hz band. At 1.0 Hz, the Lg-wave Q over the whole island continent varies from 50 to 1250 with an average value of 850. Significant regional variations in the Lg-wave Q images tie well with many geological features and boundaries in Australia. The cratons in western, northern and southern parts of Australia usually have higher Q values (700–1250), while the volcanic regions, sedimentary basins and orogenic areas in eastern Australia are characterized by increased attenuation (lower Q values, 50–650). We determine the frequency-dependent Q of Lg waves for different blocks across Australia, and find the frequency dependence of Q is much more complex than the traditional single power law representation. When combined with the assumed geometrical spreading relation, the Lg Q maps provide a new way of assessing potential ground motion across the continent for any event location.