Consistency parameters of focal mechanism for the ML3.9 Jinzhai, Anhui, earthquake swarm sequence in 2014
-
摘要: 首先采用P波、 SV波和SH波的极性和振幅比联合求解2014年安徽省金寨ML3.9震群序列的震源机制解， 并在此基础上计算得到该震群序列的震源一致性参数和P轴方位角随时间的变化； 然后基于震区附近3个台站记录到的该震群序列的地震波形， 计算其体波谱振幅相关系数， 同时读取震区附近3个台站记录到的该震群序列中115次ML≥1.5地震的极性. 研究结果表明： 金寨ML3.9震群序列的地震震源机制解绝大多数为压性走滑型， P轴方位角较为一致； 其震源一致性参数处于较低水平， 体波谱振幅相关系数较高； 台站所记录到的地震极性也较为一致. 该结果表明金寨ML3.9震群序列的震源一致性程度非常高.
-
关键词:
- 金寨ML3.9震群序列 /
- 震源机制解 /
- 谱振幅相关系数 /
- 震源一致性参数
Abstract: The Jinzhai ML3.9 earthquake swarm sequence occurred in Guanmiao town, Jinzhai county, Anhui Province in 2014, which continued in high activity frequency for a long duration. The focal depths of earthquakes in Jinzhai swarm were all shallow and the region was about 5 kilometers. Firstly, the consistency parameters of focal mechanism and the change in P-axis azimuth with time for the Jinzhai sequence have been obtained from the focal mechanism data which were solved by combining the polarity of P, SV and SH waves with their amplitude ratios. Then the correlation coefficients of spectral amplitude of the Jinzhai sequence were calculated based on the seismic waveforms recorded by three stations near the epicenter of Jinzhai ML3.9. And the polarity of first motions of 115 earthquakes with ML≥1.5 recorded by three stations close to the earthquake region had been read at the same time. The results show that the main type of focal mechanism of Jinzhai earthquake swarm sequence is transpressional strike-slipping， and the P-axis azimuth is more consistent for the earthquakes. The consistency parameters of focal mechanism are at a low level, while the correlation coefficient of spectral amplitude are relatively high, and the polarities of first motion recorded by stations are also consistent. All mentioned above suggests that the consistency parameters of focal mechanism of Jinzhai earthquake sequence are in a very high degree. -
-
![]()
图 1 金寨ML3.9地震震中位置及震区断裂和台站分布
Figure 1. Epicentral location of Jinzhai ML3.9 earth-quake and distribution of faults and stations Solid triangles represent fixed seismic stations， and open triangles represent temporary ones
![]()
图 2 用双差定位法得到的金寨震群地震精定位结果
Figure 2. Relocation result of the Jinzhai earthquake swarm sequence by using double difference location algorithm
![]()
图 3 金寨震群序列的M-t及震源机制解P轴方位角的时序分布
Figure 3. M-t plots and temporal distribution of the P-axis azimuth of the focal mechanism for the Jinzhai earthquake swarm sequence
![]()
图 4 金寨震群序列震源一致性参数的时序分布
Figure 4. Temporal distribution of the consistency parameters of focal mechanism for the Jinzhai earthquake swarm sequence
![]()
图 5 金寨震群的M-t及体波谱振幅相关系数时序分布 (a)ML≥1.5；(b)ML≥2.0
Figure 5. M-t plots and temporal distribution of the correlation coefficient of spectral amplitude for the Jinzhai earthquake swarm sequence (a)ML≥1.5；(b)ML≥2.0
![]()
图 6 商城、 金寨和麻城台所记录到的金寨震群地震极性时间变化图 +1表示Pg波垂直向极性为正，0表示极性不清，-1表示Pg波垂直向极性为负
Figure 6. Variations of seismic initial polarity recorded by the stations Shangcheng， Jinzhai and Macheng from the top down +1 represents upcast polarity of vertical Pg wave，-1 represents downcast polarity， and 0 represents indistinct
表 1 速度结构模型
Table 1 Model of velocity structure
深度/km 层厚/km vP/(km·s-1) vS/(km·s-1) 0—2 2 4.98 2.94 2—5 3 5.22 3.01 5—10 5 5.59 3.23 10—15 5 6.12 3.53 15—20 5 6.46 3.73 20—25 5 6.45 3.72 25—33 8 7.03 4.06 33—40 7 8.00 4.62 
下载: 导出CSV
表 2 金寨震群ML≥3.0地震的震源机制解
Table 2 Focal mechanism solutions of ML≥3.0 earthquakes of the Jinzhai earthquake swarm
发震时间
年-月-日时：分 北纬/° 东经/° ML 节面Ⅰ 节面Ⅱ P轴 T轴 方位角/° 倾角/° 滑动角/° 方位角/° 倾角/° 滑动角/° 方位角/° 倾角/° 方位角/° 倾角/° 2014-10-22 04:29 31.52 115.52 3.0 127 83 29 33 61 172 257 14 354 26 2014-10-22 13:34 31.52 115.52 3.7 125 83 19 33 71 173 258 8 350 18 2014-10-26 01:25 31.52 115.52 3.9 129 69 22 31 69 158 260 0 350 30 2014-10-26 02:16 31.52 115.51 3.7 127 83 29 33 61 172 257 14 354 26 2014-10-26 23:05 31.52 115.51 3.3 121 85 30 28 61 174 251 17 349 24 2014-10-28 19:33 31.52 115.52 3.6 138 82 24 44 67 171 269 10 3 23 2014-10-29 09:38 31.51 115.51 3.0 128 76 32 30 59 164 256 11 353 33 2014-11-06 06:22 31.51 115.53 3.6 126 82 24 32 67 171 257 10 351 23 2014-11-06 06:31 31.52 115.52 3.3 125 83 19 33 71 173 258 8 350 18 2014-11-11 03:08 31.51 115.52 3.7 141 85 30 48 61 174 271 17 9 24 2014-11-11 07:08 31.51 115.51 3.4 140 78 22 46 69 167 272 6 4 24 2014-11-11 07:17 31.52 115.51 3.0 323 81 -5 53 85 -171 278 10 188 3
下载: 导出CSV
计量
- 文章访问数: 960
- HTML全文浏览量: 618
- PDF下载量: 29
