| 岫岩陨石坑三维Q值层析成像 |
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| 引用本文： | 樊计昌,刘明军,赵成彬,海燕,莘海亮.岫岩陨石坑三维Q值层析成像[J].地球物理学报,2010,53(10):2367-2375. |
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| 作者姓名： | 樊计昌 刘明军 赵成彬 海燕 莘海亮 |
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| 作者单位： | 中国地震局地球物理勘探中心,郑州 450002 |
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| 基金项目： | 国家自然科学基金项目 |
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| 摘 要： | 到2009年为止,世界上已发现176个陨石撞击坑.从20世纪80年代起,中国学者从地质、地球化学和地质钻探角度推断并证实辽宁省岫岩县的一个环形构造为陨石撞击而成,但该坑的深部构造及整体特征仍有待地球物理方法来确认.本文从地震勘探角度利用三维Q值层析成像方法首次对岫岩坑的地震波衰减结构进行了研究,以便对该撞击构造有个整体认识.Q值结构对了解地壳的非弹性性质、地壳介质非均匀性有着重要意义.利用基于吸收特征时间t*的三维Q值层析成像方法,计算了岫岩坑地震折射方阵的观测数据的振幅谱,并通过拟合振幅谱得到了反映地震波衰减的t*.利用t*通过三维Q值层析成像方法获得了该坑的三维Q值结构.结果表明:该陨石坑内从地表到深度100 m的Q值层对应坑内上部107 m厚的湖泊相沉积物,深度100~300 m的Q值层对应坑内下部厚度为188 m的角砾岩堆积透镜体.深度300~700 m的Q值层对应角砾岩堆积透镜体下面的下元古界变质岩系程度较低的撞击破碎层.大约250 m深处的波阻抗界面与地质钻孔的260 m深处的陨石冲击分界面相对应.
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| 关 键 词： | 陨石撞击坑 三维Q值层析成像 吸收特征时间 Q值结构 地震波形 岫岩 |
| 收稿时间： | 2010-02-09 |
Three-dimensional Q tomography for Xiuyan meteorite impact crater |
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| FAN Ji-Chang,LIU Ming-Jun,ZHAO Cheng-Bin,HAI Yan,XIN Hai-Liang.Three-dimensional Q tomography for Xiuyan meteorite impact crater[J].Chinese Journal of Geophysics,2010,53(10):2367-2375. |
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| Authors: | FAN Ji-Chang LIU Ming-Jun ZHAO Cheng-Bin HAI Yan XIN Hai-Liang |
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| Institution: | Geophysical Exploration Center, China Earthquake Administration, Zhengzhou, 450002, China |
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| Abstract: | Until 2009, 176 meteorite impact craters have been found in the world. Since the 80's of 20th century, Chinese scholars have confirmed, from geological, geochemical and drilling data, that a circular structure was formed by meteorite impacting in Xiuyan County, Liaoning Province. But the deep structures and the overall characteristics of the crater need still to be confirmed by using geophysical methods. In this paper, three-dimensional Q structure has been obtained for the first time by using seismic refraction data in order to get a total understanding of the crater. Q value structure is of great significance for understanding the non-elastic and non-uniform nature of the crust. Using three-dimensional Q tomography method based on absorption characteristic time t*, the amplitude spectra have been obtained and by fitting the amplitude spectrum, t*values have been obtained, which reflect seismic wave attenuation. The three-dimensional Q value structure has been obtained by using t*values through three-dimensional Q tomography method. The results showed that the Q-value layer from the surface to the depth of 100 m within the crater corresponds to the upper 107 m thick lake sediments, the Q-value layer from the depth of 100m to 300 m corresponds to the lower 188m thick breccia accumulation lens. The Q-value layer from the depth of 300 m to 700 m corresponds to the broken Lower Proterozoic metamorphic rock layer with less impacting. The wave impedance interface about 250 m deep corresponds to the meteorite impact interface confirmed by geological drilling at the 260 m depth. |
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| Keywords: | Meteorite impact crater Three-dimensional Q tomography Absorption characteristic time Q value structure Seismic waves Xiuyan |
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