地震研究

利用1978～2009年川滇地区的124个地震震源机制解资料,采用对震源机制参数统计的方法,详细分析了地震断层类型和川滇地区的现代构造应力场特征。结果表明,云南地区(21°～28°N,97°～108.8°E)主要受近N-S向的水平挤压力影响,区域应力场背景以水平作用力为主; 四川地区(28°～34.5°N,97°～108.8°E)由于平均P,T轴的仰角接近水平,构造应力场接近水平,主要受近E-W向挤压力作用,断层面较陡,受水平剪切力作用。川滇地区走滑型地震较多,主要分布于云南地区,四川地区内发生的地震类型较为分散且每种类型都有。

Basing on 124 focal mechanisms data from 1978 to 2009 in Sichuan-Yunan area, we analyzed the fault type of earthquake and the characteristic of modern tectonic stress field in Yunnan-Sichuan area by the statistic method of focal mechanisms parameters. The results showed that it was influenced by horizontal compression in nearly NS direction in Yunnan area(21°～28°N, 97°～108.8°E), and the main characteristic of regional stress field background is characterized by horizontal compression. Because of the average plunges of P-axis and T-axis were close to horizontal, the tectonic stress field which is close to horizontal mainly influenced by compression in nearly EW direction in Sichuan area(28°～34.5°N, 97°～108.8°E). The fault plane which was influenced by horizontal shear tress is stepper. The main type of fault is strike-slipe in Sichuan-Yunnan area, and mainly distributed in Yunnan. The earthquake occurred in Sichuan area had many types and scattering distribution.

引言
1 资料和方法
2 震源机制解参数的统计分析与区域应力场
3 地震震源断层类型
4 结论与讨论

图1 川滇地区124个地震震源机制解分布<br/>Fig.1 Distribution of the focal mechanism solutions of 124 earthquakes in Sichuan-Yunan region

图1 川滇地区124个地震震源机制解分布
Fig.1 Distribution of the focal mechanism solutions of 124 earthquakes in Sichuan-Yunan region

图2 三角形地震类型图解法(据马文涛等(2004))<br/>Fig.2 Graphic of triangle seismic classification (based on Ma et al(2004))

图2 三角形地震类型图解法(据马文涛等(2004))
Fig.2 Graphic of triangle seismic classification (based on Ma et al(2004))

表1 震源机制解类型(据崔效锋等(2005))<br/>Tab.1 Types of focal mechanism solutions(based on Cui et al(2005))

表1 震源机制解类型(据崔效锋等(2005))
Tab.1 Types of focal mechanism solutions(based on Cui et al(2005))

图3 川滇地区震源机制解节面倾角,P、T、B轴仰角玫瑰图<br/>(a)节面倾角;(b)P轴仰角;(c)T轴仰角;(d)B轴仰角<br/>Fig.3 Rose diagrams of plunges of P、T、B axes and dip of nodal plane of focal mechanism solutions in Sichuan-Yunan region(a)dip of nodal plane;(b)plunges of P axe;(c)plunges of T axea;(d)plunges of B axe

图3 川滇地区震源机制解节面倾角,P、T、B轴仰角玫瑰图
(a)节面倾角;(b)P轴仰角;(c)T轴仰角;(d)B轴仰角
Fig.3 Rose diagrams of plunges of P、T、B axes and dip of nodal plane of focal mechanism solutions in Sichuan-Yunan region(a)dip of nodal plane;(b)plunges of P axe;(c)plunges of T axea;(d)plunges of B axe

表2 研究区震源机制解参数统计<br/>Tab.2 Parameters statistics of the focal mechanism solutions

表2 研究区震源机制解参数统计
Tab.2 Parameters statistics of the focal mechanism solutions

图4 川滇地区震源机制解节面走向和滑动角玫瑰图<br/>(a)节面走向;(b)节面滑动角;(c)P轴方位;(d)T轴方位<br/>Fig.4 Rose diagrams of strick and slip of nodal plane of focal mechanism solutions in Sichuan-Yunan region (a)strick of nodal plane;(b)slip of nodal plane;(c)azimuths of P axes;(d)azimuths of T axes

图4 川滇地区震源机制解节面走向和滑动角玫瑰图
(a)节面走向;(b)节面滑动角;(c)P轴方位;(d)T轴方位
Fig.4 Rose diagrams of strick and slip of nodal plane of focal mechanism solutions in Sichuan-Yunan region (a)strick of nodal plane;(b)slip of nodal plane;(c)azimuths of P axes;(d)azimuths of T axes

图5 川滇地区P轴方位及构造应力场方向示意图(a)云南地区;(b)四川地区<br/>Fig.5 Schematic diagram of azimuths of P-axe and orientation of tectonic stress field in Sichuan-Yunnan region(a)Yunnan area;(b)Sichuan area

图5 川滇地区P轴方位及构造应力场方向示意图(a)云南地区;(b)四川地区
Fig.5 Schematic diagram of azimuths of P-axe and orientation of tectonic stress field in Sichuan-Yunnan region(a)Yunnan area;(b)Sichuan area

图6 川滇地区震源机制解分布图<br/>Fig.6 Distribution of focal mechanisms in Sichuan-Yunnan region

图6 川滇地区震源机制解分布图
Fig.6 Distribution of focal mechanisms in Sichuan-Yunnan region

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备注

引言

1 资料和方法

2 震源机制解参数的统计分析与区域应力场

3 地震震源断层类型

4 结论与讨论

期刊信息