| 强台风对汶川大地震和昆仑山大地震“震前扰动”影响的分析 |
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| 引用本文： | 胡小刚,郝晓光.强台风对汶川大地震和昆仑山大地震“震前扰动”影响的分析[J].地球物理学报,2009,52(5):1363-1375. |
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| 作者姓名： | 胡小刚 郝晓光 |
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| 作者单位： | 中国科学院测量与地球物理研究所动力大地测量重点实验室， 武汉 430077 |
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| 基金项目： | 国家自然科学基金，质检公益性行业科研专项基金 |
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| 摘 要： | 2008年8.0级汶川大地震发生前约40 h起，中国地震局测震台网中的宽带地震仪、重力仪和倾斜仪都记录到了明显的低频扰动现象.然而，在此期间西太平洋上空产生了一次强台风Rammasun（威马逊）；与此类似，2001年8.1级昆仑山大地震发生前约60 h起，国家地震局测震台网中的宽带地震仪也记录到了明显的低频扰动现象，在此期间中国南海上空产生了一次强台风LingLing（玲玲）.本文针对这两大地震的“震前扰动”现象进行了研究，旨在探讨其“震前扰动”现象是否与台风引起的巨浪产生的地脉动效应有关.我们的研究结果表明：在中国内陆观测到的异常扰动与台风路径以及台风的强度密切相关.近海台风可在中国大陆内地引起明显的异常扰动；而远离大陆海岸位于深水海域上空的台风，很难在中国大陆内地引起明显的异常地脉动变化.台风LingLing的路径距离中国海岸最近处仅有约700 km，而台风Rammasun距离中国大陆海岸最近处却达1300 km.本文的对比分析研究表明：路径和强度类似于LingLing的台风在中国内陆可引起明显的异常扰动.因此，中国内陆和沿海许多地震台记录到的昆仑山大地震的“震前扰动”源于LingLing地脉动效应的可能性较大；但位于新疆的地震台记录到的扰动信号频率却明显偏低，这一现象值得注意.路径和强度类似于Rammasun的台风很难在中国内陆引起明显的异常扰动，因此汶川大地震的“震前扰动”完全源于台风Rammasun地脉动效应的可能性较小.汶川大地震的“震前扰动”产生的原因和机理值得我们去进行深入的探讨和研究.
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| 关 键 词： | 2008汶川大地震 2001昆仑山大地震 震前扰动 异常地脉动 台风 小波分析 |
| 收稿时间： | 2009-1-24 |
| 修稿时间： | 2009-4-24 |
An analysis of the influences of typhoon on anomalous tremors before the great Wenchuan and Kunlunshan earthquakes |
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| HU Xiao-Gang,HAO Xiao-Guang.An analysis of the influences of typhoon on anomalous tremors before the great Wenchuan and Kunlunshan earthquakes[J].Chinese Journal of Geophysics,2009,52(5):1363-1375. |
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| Authors: | HU Xiao-Gang HAO Xiao-Guang |
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| Institution: | Key Laboratory of Dynamical Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China |
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| Abstract: | Anomalous tremors were widely recorded by seismographs, gravimeters and tiltmeters in the National Digital Seismograph Network of China (NDSN) about 40 hours before the 2008 MS 8.0 Wenchuan earthquake. However, a violent typhoon, named Rammasun, was taken place over the western Pacific before the earthquake. Similarly, anomalous tremors also appeared about 60 hours before the 2001 MS8.1 Kunlunshan earthquake, while a violent typhoon LingLing was produced. In this paper, we study if these anomalous tremors before the great earthquakes are relevant to the typhoon events. Our results show that many anomalous tremors in the inner-land appeared during typhoon and their amplitudes depend on the distance from the track of typhoon and the strength of typhoon. A violent typhoon close to the coast of China can cause strong microseisms which can be widely observed in the inner-land of China, but a typhoon far from the coast of China cannot do that. The nearest distance from the track of LingLing to the coast of China is about 700 km, and that for Rammasun is about 1300 km. Our investigation shows that a typhoon which has a similar track and strength as that of LingLing can surely cause significant anomalous tremor in the inner-land of China, but it is contrary for a typhoon similar to Rammasun. Anomalous tremors recorded by many seismographs in NDSN before the Kunlunshan earthquake are most likely caused by LingLing, however, strong anomalous tremors in Xinjiang region have low frequencies. We suggest that the anomalous tremors before the Wenchuan earthquake are less likely to be entirely attributed to Rammasun. It is worthwhile to make further study of the cause and mechanism of anomalous tremors before the Wenchuan earthquake. |
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| Keywords: | The 2008 great Wenchuan earthquake The 2001 great Kunlunshan earthquake Anomalous tremors before earthquakes Anomalous microseisms Typhoon Wavelet analysis |
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