| 利用时移层析成像方法揭示与2014年云南鲁甸MS6.5地震有关的P波速度变化 |
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| 引用本文： | 曹颖,黄江培,钱佳威,付虹.利用时移层析成像方法揭示与2014年云南鲁甸MS6.5地震有关的P波速度变化[J].地球物理学报,2021,64(5):1569-1584. |
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| 作者姓名： | 曹颖 黄江培 钱佳威 付虹 |
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| 作者单位： | 云南省地震局,昆明 650224;中国科学技术大学地球和空间科学学院,合肥 230026 |
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| 基金项目： | 云南省地震局科技专项(2020ZX04)资助. |
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| 摘 要： | 基于双差层析成像的时移层析成像方法能够获得不同时间段之间的地下介质的速度变化,且不同的数据分布和质量对结果影响较小.在本研究中我们使用云南地震区域台网所记录到的P波绝对到时及相对到时数据,利用时移层析成像方法得到了2014年鲁甸M S6.5地震发生前后震源区高精度的P波速度变化的时空分布.结果表明:2014年鲁甸地震发生后,震源区同震期P波速度下降,但没有下降至最大,而是在震后1—4个月内下降至最大,接着P波速度开始上升,震源区开始愈合,愈合过程从浅层逐渐发展至深层,逐渐恢复至震前水平.同时发现在空间上P波速度变化与余震分布变化相一致,鲁甸地震同震应力变化与速度变化之间也有较好的一致性,所以认为地震引起的应力变化是造成鲁甸地震速度变化的一个重要原因,余震的动态和静态应力造成了震源区介质物理属性的改变从而影响了P波速度的变化.
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| 关 键 词： | 鲁甸地震 时移层析成像 P波速度变化 |
Application of time-lapse seismic tomography based on double-difference tomography to reveal P wave velocity changes related to the 2014 Ludian Ms6.5 earthquake |
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| CAO Ying,HUANG JiangPei,QIAN JiaWei,FU Hong.Application of time-lapse seismic tomography based on double-difference tomography to reveal P wave velocity changes related to the 2014 Ludian Ms6.5 earthquake[J].Chinese Journal of Geophysics,2021,64(5):1569-1584. |
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| Authors: | CAO Ying HUANG JiangPei QIAN JiaWei FU Hong |
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| Institution: | (Yunnan Earthquake Agency,Kunming 650224,China;School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China) |
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| Abstract: | Various studies have reported on temporal changes of seismic velocities in the crust before and after earthquake.New time-lapse seismic tomographic scheme based on double-difference tomography could obtain temporal velocity variations of the subsurface medium in different time periods,and it is less affected by different data distribution and quality in different time periods.In this study,we used the absolute and relative arrival data of P-wave recorded by Yunnan regional seismic network to obtain the high precision spatial-temporal distribution of P-wave velocity changes before and after the 2014 Ludian M S6.5 earthquake by using tomoTDD method.The results show that after the Ludian Earthquake,the P-wave velocity in the source area decreased during the coseismic period,but did not drop to the minimum.It dropped to its minimum within 1—4 months after the main shock.Then P-wave velocity began to rise and the source area began to heal.The healing process developed from the shallow layer to the deep layer,and finally,restored to the level before the earthquake.At the same time,we found that the spatial change of P-wave velocity is consistent with the change of aftershock distribution.There is a good consistency between the variation of coseismic coulomb stress and P-wave velocity change.Therefore,we consider that the change of static stress caused by the earthquake is an important reason for the change of P-wave velocity.The dynamic and static stress of the aftershock results in the change of physical properties of medium in the source area,which affects the change of P-wave velocity. |
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| Keywords: | Ludian earthquake Time-lapse seismic tomographic scheme P-wave velocity variation |
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