利用连续重力观测约束2014智利Iquique地震的震源机制解

发布时间：2018-04-30 18:50

本文选题：Iquique地震 + 震源机制解　；参考：《地球物理学报》2016年03期

【摘要】：2014年4月1日,智利北部Iquique地区近海发生MW8.1地震,地震发生之后,国际上一些著名的地震科研机构和学者采用不同的数据和方法计算得到此次地震的震源机制解,但这些结果存在较大差异.地球长周期自由振荡的振幅主要依赖于地震矩的大小及地震断层的破裂方式,可以很好地约束地震震源机制.因此,本文根据2014年Iquique地震现有的6个不同震源机制解模拟计算了该地震激发的自由振荡信号,并与全国连续重力台网中16个弹簧重力仪的观测结果进行比对,基于1.5~5.3mHz的球型简正模分析和约束了Iquique地震的震源机制解.研究发现,基于美国地质调查局WPhase Moment Tensor Solution反演的震源机制解的自由振荡模拟值与实际观测符合最好,其相应的震级能较好反映Iquique地震释放的总能量,而利用海啸数据反演的标量地震矩偏小,联合远场和近场长周期观测数据反演可显著改善震源机制解.另外,还基于格尔木重力台站的模拟值与观测值定量分析了不同震源机制解参数对自由振荡振幅的影响.结果表明地震的标量地震矩M0对自由振荡振幅的影响最大,而断层走向、倾角、滑动方向角和震源深度对自由振荡的振幅影响相对较小.
[Abstract]:On April 1, 2014, a MW8.1 earthquake occurred off the coast of Iquique region in northern Chile. After the earthquake occurred, some famous international seismological research institutions and scholars used different data and methods to calculate the focal mechanism solution of the earthquake. But these results are quite different. The amplitude of the earth's long-period free oscillation mainly depends on the magnitude of the seismic moment and the rupture mode of the seismic fault, which can restrain the seismic focal mechanism well. Therefore, based on the existing six focal mechanism solutions of the 2014 Iquique earthquake, the free oscillation signals generated by the earthquake are simulated and calculated, and compared with the observations of 16 spring gravimeters in the national continuous gravity network. The spherical normal mode analysis based on 1.5~5.3mHz constrains the focal mechanism solution of Iquique earthquake. It is found that the free oscillation simulation value of the focal mechanism solution based on the WPhase Moment Tensor Solution inversion of the United States Geological Survey is in the best agreement with the actual observation, and its corresponding magnitude can better reflect the total energy released by the Iquique earthquake. However, the scalar seismic moment from the tsunami data inversion is small, and the focal mechanism solution can be significantly improved by combining the far-field and near-field long-period observation data inversion. In addition, based on the simulated and observed values of Golmud gravity station, the effects of different focal mechanism solution parameters on the amplitude of free oscillation are quantitatively analyzed. The results show that the scalar seismic moment M0 has the greatest influence on the amplitude of free oscillation, while the strike of fault, dip angle, slip direction angle and focal depth have relatively little effect on the amplitude of free oscillation.
【作者单位】：中国地震局地震研究所(中国地震局地震大地测量重点实验室);中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室;
【基金】：科研院所基本科研业务费(中国地震局地震研究所所长基金)(IS201526225) 大地测量与地球动力学国家重点实验室开放基金(SKLGED2015-1-2-EZ) 国家自然科学基金(41404064;41374088)资助
【分类号】：P315.33

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