| 云南地区背景噪声层析成像 |
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| 引用本文： | 郑定昌,盖增喜,杨润海,闵照旭,唐有彩,姜明明,庞卫东.云南地区背景噪声层析成像[J].地震学报,2014,36(4):602-615. |
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| 作者姓名： | 郑定昌 盖增喜 杨润海 闵照旭 唐有彩 姜明明 庞卫东 |
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| 作者单位： | 1.中国北京 100871 北京大学地球与空间科学学院 |
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| 基金项目： | 国家自然科学基金(41074029);云南省基金项目(2009ZC179M,2010ZC143)联合资助 |
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| 摘 要： | 选取云南省区域台网46个地震台从2007年11月—2009年10月的宽频带噪声数据， 通过互相关方法获得经验格林函数， 采用自适应时频分析方法获取相速度频散曲线， 并且反演得到8—40 s的相速度分布图. 研究结果表明: 云南地区短周期相速度低速异常与地表断裂带分布和沉积层厚度密切相关； 在短周期相速度分布图上， 红河断裂南北段呈现差异， 表明红河断裂南北段周边介质存在物性差异， 这可能是造成地震活动南北差异的主要原因； 长周期相速度分布图显示， 红河断裂和小江断裂带存在低速异常， 可能是切穿地壳的超壳断裂, 该低速异常可能与深部热作用有关; 红河断裂和小江断裂带交汇地区存在高速异常， 该高速异常体对川滇块体深部介质向南运动可能起到了阻挡的作用. 本文结果为下一步反演云南地区的三维剪切波速度结构奠定了基础.
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| 关 键 词： | 背景噪声 相速度 面波层析成像 地壳结构 云南地区 |
| 收稿时间： | 2013-06-25 |
Broadband ambient noise tomography in Yunnan Province |
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| Affiliation: | 1.School of Earth and Space Sciences, Peking University, Beijing 100871, China2.Earthquake Administration of Yunnan Province, Kunming 650224, China |
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| Abstract: | In this paper, the Rayleigh wave empirical Green’s functions are retrieved from cross-correlation of the ambient noise data recorded by the 46 permanent stations of Yunnan Regional Seismic Network from November 2007 to October 2009. The regional phase velocities with periods from 8 s to 40 s are then inverted using the generalized Backus-Gilbert method. The results show that low-velocity anomalies at shorter periods associate with the faulting area and sedimentary basins. The difference between north and south across Honghe fault due to substantial variations at shorter period phase velocity maps coincides with distribution of earthquakes. As the period becomes longer, low-velocity anomalies around the Honghe fault and Xiaojiang fault are still visible, which suggests that they are probably correlated with the high heat flow from the deeper area and the faults have cut through the crust. The phase velocities at the junction of the Xiaojiang fault and Honghe fault exhibit high-velocity anomalies that maybe, to an extent, hinder the materials of Sichuan--Yunnan block moving towards the south. These phase velocity dispersion maps provide necessary information to construct a 3-D shear velocity model of the crust in Yunnan Province. |
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