| 2010年4月14日青海玉树7.1级地震序列中小地震辐射能量的估计 |
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| 引用本文： | 华卫,陈章立,郑斯华.2010年4月14日青海玉树7.1级地震序列中小地震辐射能量的估计[J].地球物理学进展,2012,27(1):8-17. |
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| 作者姓名： | 华卫 陈章立 郑斯华 |
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| 作者单位： | 中国地震局地震预测研究所,北京,100036 |
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| 基金项目： | “十一五”科技支撑课题 |
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| 摘 要： | 本文利用震后架设的4个流动台站和震源区周围3个固定台站记录到的青海玉树7.1级地震序列波形资料,资料时间截止到2010年5月19日.经过传播路径效应和场地响应校正后,估算了玉树地震序列中80个中小地震的辐射能量.比较了辐射能量估计中不同方法之间结果存在的差异性,首次考虑了由于仪器频带宽度的限制而造成的中小地震辐射能量的低估与补偿问题,得到以下主要结论:(1)分别采用Andrews方法、震源实际谱方法(区分能量补偿前和后二种情况)和根据理论模型并将积分上限外推到所计算地震拐角频率的10倍的方法(理论谱方法)计算出的中小地震辐射能量4种结果基本上位于同一个量级水平之上,表明结果具有一定的可靠性和稳定性.这其中,Andrews方法得到的辐射能量最低,理论谱方法得到的结果最高,而由实际谱方法得到的地震辐射能量介于两者之间.(2)由古登堡经验公式得到的地震辐射能量远高于上述4种方法计算出的结果,能够达到理论谱方法结果的4倍,而且随震级的增大,由它带来的辐射能量的高估趋势更加明显.(3)由于没有考虑地震能量的补偿,Andrews方法得到的地震辐射量明显偏低.用两种不同方法进行地震辐射能量补偿后得到的结果比较接近,但考虑到仪器频带上限值设定的复杂性,认为由理论谱方法计算中小地震的辐射能量更加合适.(4)经过能量补偿后地震辐射能量要高于未作能量补偿的结果,能量补偿带来的辐射能量增加的作用对于小地震更加明显.在本文研究范围之内,不同方法得到的折合能量均明显存在随地震矩的增大而增大的现象,反映出玉树余震序列中大震地震辐射效率高于小震.
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| 关 键 词： | 地震辐射能量 能量补偿 玉树地震序列 中小地震 |
Estimation of radiated seismic energy for moderate and small earthquakes in Ms 7.1 sequence on 14 April 2010 Yushu, Qinghai |
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| HUA Wei
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CHEN Zhang-li
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ZHENG Si-hua.Estimation of radiated seismic energy for moderate and small earthquakes in Ms 7.1 sequence on 14 April 2010 Yushu, Qinghai[J].Progress in Geophysics,2012,27(1):8-17. |
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| Authors: | HUA Wei CHEN Zhang-li ZHENG Si-hua |
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| Institution: | (Institute of Earthquake Science,CEA,Beijing 100036,China) |
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| Abstract: | Radiated seismic energy for 80 earthquakes were estimated using the data of Yushu Ms 7.1 earthquake sequence in Qinghai recorded by 4 temporary stations disposed after the mainshock and 3 fixed stations around the source region with the deadline on 19 May 2010,after the calibration of wave travel path effect and the site response.We compare the difference among the results calculated by various methods and take into account the underestimate of the radiated seismic energy for moderate and small earthquake due to the limited recording bandwidth and the energy compensation.Our results show that(1) Radiated seismic energy of moderate and small earthquakes is estimated by Andrews’ method.The actual spectrum’s method is based on actual spectrum(handled separately pre-and post-the energy compensation) and the theory’s method extends the upper integration limit to 10 times the corner frequency of the event we studied are in same level,showing that the results have high reliability and stability.Among them,the values of radiated energy derived from Andrews’ method are lowest and that of the theory’s method are highest,results calculated by the actual spectrum’s method are between them.(2) The results of radiated energy calculated by Gutenberg empirical formula are higher than that of aforesaid 4 results and come up to 4 times that of the theory’s method.With the increase in magnitude,the tendency of overestimate of the radiated seismic energy become more apparently.(3) As lack of energy compensation,the results of Andrews’ method seem to be lower.The two results of radiated seismic energy after compensated by various methods achieve to be approach and the theory’s method is considered to be more rational used for calculating the radiated energy for moderate and small earthquake because the complexity existed in the determination for upper bound of recording bandwidth.(4) The results for radiated energy after the energy compensation are bigger than that of before the energy compensation and the increase in radiated energy due to energy compensation seems to be more apparently for small earthquake.Within the data we studied,scale energy calculated by various methods increasing with the increasing seismic moment,indicating that the radiated efficiency for big earthquake is bigger than that of small earthquake in Yushu earthquake sequence. |
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| Keywords: | radiated seismic energy energy compensation Yushu earthquake sequence moderate and small earthquake |
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