地震研究

根据地震破裂过程中的多普勒效应,利用多台波谱参数推算九江—瑞昌M_S5.7地震的震源破裂参数,得到主震的破裂方位角φ₀≈319.6°,破裂速度约为2.3 km/s,用最小二乘法拟合的相关系数极值约为0.80。在此基础上,分别计算了主震在4.8级强余震的两个节面上的静态库仑应力变化量,结果显示:主震在4.8级余震节面Ⅰ、Ⅱ上的静态库仑应力变化均为正值,分别为0.48 MPa和0.02 MPa。主震在节面Ⅰ、Ⅱ上产生的静态库仑应力的变化十分接近。应力增加的区域主要位于

According to the Doppler Effect in the earthquake rupture process,we use the multi-station spectrum to calculate rupture parameters of the Jiujiang-Ruichang M_S5.7 earthquake in Jiangxi.We get the results that the rupture azimuth is about 319.6°,the rupture velocity is about 2.3 km/s,and the fitted minimum correlation-coefficient is about 0.80 by minimum squares.And on this basis,We calculate the variation of static Coulomb stress separately in the two rupture planes of the M_S4.8 aftershock.The results show that the variation of the static Coulomb stress separately on two nodal planes are positive,the values are about 0.48 MPa and 0.02 MPa respectively.The variations of static Coulomb stress on nodalⅠ and Ⅱ are very close.Stress-increasing area is mainly located on the right of the main earthquake fault.Stress-reducing area is mainly located to the south of the epicenter.Most of the aftershocks occur in the static Coulomb stress-increasing region,especially on the nodal.This shows the Coulomb failure stress variation caused by the main shock has an important role in triggering of the M_S4.8 aftershock,and also conductive to majori aftershocks' occurrence.

引言
1 利用波谱参数推算震源的破裂参数
2 资料选取与震源区构造背景
3 主震震源的破裂参数
4 余震的静态应力触发研究
5 结论与讨论

表1 破裂方位角与b1、b2的关系表<br/>Tab.1 Relation between facture azimuth and b1,b2

表1 破裂方位角与b1、b2的关系表
Tab.1 Relation between facture azimuth and b1,b2

表2 台站基本要素及震源谱拐角频率表<br/>Tab.2 Seismic station's basic parameter and corner frequency of source spectrum

表2 台站基本要素及震源谱拐角频率表
Tab.2 Seismic station's basic parameter and corner frequency of source spectrum

图1 MS5.7主震与记录台站分布图(a)和震源区(图1a中方框内区域)地质构造简图(b)<br/>Fig.1 Distribution of the MS5.7 earthquake and recording stations(a)and focal area's(in the box of fig.1 a)geological structure diagram(b)

图1 MS5.7主震与记录台站分布图(a)和震源区(图1a中方框内区域)地质构造简图(b)
Fig.1 Distribution of the MS5.7 earthquake and recording stations(a)and focal area's(in the box of fig.1 a)geological structure diagram(b)

图2 拟合相关系数随破裂方位角的变化<br/>Fig.2 Variation of the fitted correlation coefficient with the rupture azimuth

图2 拟合相关系数随破裂方位角的变化
Fig.2 Variation of the fitted correlation coefficient with the rupture azimuth

表3 主震震源的破裂参数<br/>Tab.3 Rupture parameters of the main earthquake source

表3 主震震源的破裂参数
Tab.3 Rupture parameters of the main earthquake source

表4 4.8级余震破裂面上库仑破裂应力变化<br/>Tab.4 Variation of Coulomb failure stress on rupture surfaces of MS 4.8 aftershock

表4 4.8级余震破裂面上库仑破裂应力变化
Tab.4 Variation of Coulomb failure stress on rupture surfaces of MS 4.8 aftershock

图3 主震在4.8级余震节面Ⅰ(a)和节面Ⅱ(b)上产生的静态库仑破裂应力变化<br/>Fig.3 Changes of static coulomb stress on nodalⅠ(a)and nodal Ⅱ(b)of MS 4.8 aftershock

图3 主震在4.8级余震节面Ⅰ(a)和节面Ⅱ(b)上产生的静态库仑破裂应力变化
Fig.3 Changes of static coulomb stress on nodalⅠ(a)and nodal Ⅱ(b)of MS 4.8 aftershock

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备注

引言

1 利用波谱参数推算震源的破裂参数

2 资料选取与震源区构造背景

3 主震震源的破裂参数

4 余震的静态应力触发研究

5 结论与讨论

期刊信息