| 地下核爆炸Lg波的激发机制 |
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| 引用本文： | 何永锋,陈晓非,张海明.地下核爆炸Lg波的激发机制[J].地球物理学报,2005,48(2):367-372. |
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| 作者姓名： | 何永锋 陈晓非 张海明 |
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| 作者单位： | 北京大学地球与空间科学学院,北京,100871;西北核技术研究所,西安,710024;北京大学地球与空间科学学院,北京,100871 |
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| 基金项目： | 国家自然科学基金项目 (4 0 13 40 10 )资助 |
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| 摘 要： | 地下核爆炸Lg波的激发机制，目前尚未十分清楚.其中主要观点之一是源区附近由补偿线性矢量偶极源（CLVD）激发的Rg波的散射形成的S波是Lg波能量的主要来源.本文利用理论地震图模拟方法，基于东哈萨克斯坦地区速度模型，分析比较了东哈萨克斯坦地壳速度模型下的爆炸源、张裂源及CLVD源对区域震相Lg波的影响.结果表明，从能量的角度来看，CLVD源是激发Lg波的主要因素.模拟计算结果也进一步证实了CLVD源激发的Lg波振幅谱具有低谷点的特征源自于该震源所激发的Rg波；在此基础之上，检验了Patton提出的估算震源埋藏深度的经验公式.结果发现，该公式仅适用于震源埋藏深度较浅的情况（<500m）.这些结果对于进一步理解及更好地利用Lg波具有重要理论指导意义.
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| 关 键 词： | Lg波 层裂 CLVD源 低谷点 |
| 文章编号： | 0001-5733(2005)02-0367-06 |
| 收稿时间： | 2003-12-16 |
| 修稿时间： | 2004-11-16 |
The excitation of Lg wave by underground nuclear explosions |
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| HE Yong-Feng,CHEN Xiao-Fei,ZHANG Hai-Ming.The excitation of Lg wave by underground nuclear explosions[J].Chinese Journal of Geophysics,2005,48(2):367-372. |
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| Authors: | HE Yong-Feng CHEN Xiao-Fei ZHANG Hai-Ming |
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| Institution: | 1.School of Earth & Space Sciences, Peking University, Beijing 100871, China 2 Northwest Institute of Nuclear Technology, Xi'an 710024, China |
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| Abstract: | Near-Source scattering of explosion-generated Rg wave into S wave appears to be the primary contribution to the low-frequency Lg wave in underground nuclear explosions, this mechanism has been supported by analysis of regional data from several Yucca Flats, NTS explosions by Patton and Taylor (1995), who further indicated that the prominent low-frequency spectral null in Lg wave is due to Rg wave from a compensated linear vector dipole (CLVD) source. In this study, the mechanism of the excitation of Lg wave by explosions in layered earth structures of the East Kazakh test site is further analyzed by using theoretical seismograms, and the result shows that the Lg spectra indicate prominent nulls showing strong dependence on shot depth and in remarkably good agreement with those expected from Rg wave due to a CLVD source. |
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| Keywords: | Lg wave Spall Compensated linear vector dipole (CLVD) source Null |
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