Analysis of Seismogenic Structure of the Huailai ML3.4 Earthquake Swarm on January 9, 2016 in Hebei Province
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摘要: 本文采用模板识别匹配滤波方法检测2016年1月9日河北怀来ML3.4震群序列目录中遗漏的地震事件,并加入波形互相关信息对震相到时进行校正,采用盖革法进行精确定位。重新定位后震群震中呈NEE向分布,与怀涿次级盆地北缘断裂走向一致,并主要集中在该断裂的小水峪-黄土窑段。震群中最大地震ML3.4的P波初动解的一个节面走向与精定位后震中展布和断裂的走向基本一致,可推测怀涿次级盆地北缘断裂可能为怀来ML3.4震群的发震构造。震中集中分布的怀涿次级盆地北缘断裂的小水峪-黄土窑段属5个分段中滑动速率最大的段落,分析认为该震群可能是由断层慢滑动引起的。Abstract: The template recognition and matched filter method is used to detect missing earthquake events in the Huailai ML3.4 earthquake swarm on January 9, 2016 in Hebei Province, and the waveform correlation information is added to correct the earthquake phase arrival time. After the precise relocation by the Geiger method, direction of the distribution of swarm epicenters is in the NEE direction, which is consistent with the strike of the north margin fault of the Huaizhuo sub-basin. The relocated events are mainly concentrated in the Xiaoshuiyu-Huangtuyao segment of the north margin fault of the Huaizhuo sub-basin. The strike of node plane of P-wave first motion solution of ML3.4 is same as the distribution of precise relocation and the strike of the north margin fault of the Huaizhuo sub-basin. It is inferred that the north margin fault of the Huaizhuo subbasin may be the seismogenic structure of the Huailai ML3.4 earthquake swarm. The segment of the Xiaoshuiyu-Huangtuyao has the biggest slip rate among the five segments of the north margin fault of the Huaizhuo subbasin, so we conclude that the earthquake swarm may be caused by the slow slip model.
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图 3 沙城台(SHC)震相标定过程示意图
最上方黑色曲线为所选模板地震经过1—10Hz带通滤波的波形。蓝色短线表示台网震相报告给出的震相到时数据,红色表示基于波形互相关震相检测技术标定的震相到时,每条波形左侧数字为震相报告给出到时与互相关标定到时之差,单位为s(a)震群中21个地震事件在SHC台的垂直向记录波形,选取P波到时前0.5s至到时后1.5s的波形检测P波到时;(b)震群中21个地震事件在SHC台的东西向记录波形,选取S波到时前0.5 s至到时后1.5s的波形检测S波到时
Figure 3. The process of seismic phase recalibration of the Shancheng station
图 5 怀来震群精确定位前后震中分布与震群中最大地震ML 3.4震源机制解投影
黑色实心圆为精定位前震中,绿色实心圆为精定位后震中(图例同图 1)
Figure 5. The distribution of the Huailai earthquakeswarmr before and after precise relocation and the focalmechanism solution of largest event ML 3.4
表 1 所选用的模板地震
Table 1. Earthquake events selected for analysis
模板地震编号 发震时刻(北京时间) 震中经度/°E 震中纬度/°N 震源深度/km 震级/ML Eq109125827 2016/01/09 12:58:26.9 115.583 40.484 9 1.4 Eq109135316 2016/01/09 13:53:16.7 115.570 40.491 10 2.1 Eq109213407 2016/01/09 21:34:06.9 115.566 40.488 10 1.6 Eq110022547 2016/01/10 02:25:47.9 115.559 40.482 11 3.3 Eq110024840 2016/01/10 02:48:40.6 115.560 40.483 10 1.8 Eq110043829 2016/01/10 04:38:29.4 115.564 40.477 10 1.4 Eq110091104 2016/01/10 09:11:04.1 115.570 40.478 10 1.4 Eq110101138 2016/01/10 10:11:38.5 115.571 40.480 10 1.8 Eq110161609 2016/01/10 16:16:09.9 115.565 40.479 9 1.9 Eq111001245 2016/01/11 00:12:46.0 115.569 40.494 10 1.5 Eq111154502 2016/01/11 15:45:02.5 115.571 40.482 10 1.5 -
李冬圣, 李文军, 王艳荣等.2016.2014年河北涿鹿M4.3地震矩张量反演.华北地震科学, 34(1):36-40. http://youxian.cnki.com.cn/yxdetail.aspx?filename=RDDD20170905001&dbname=CAPJ2015 谭毅培, 曹井泉, 刘文兵等.2014a.2013年3月涿鹿微震群遗漏地震事件检测和发震构造分析.地球物理学报, 57(6):1847-1856. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWX201406016.htm 谭毅培, 曹井泉, 卞真付等.2014b.2013年8月河北蔚县小震群遗漏地震检测与发震构造分析.地震学报, 36(6):1022-1031. http://www.cnki.com.cn/Article/CJFDTOTAL-DZXB201406004.htm 徐锡伟, 吴卫民, 张先康等.2002.首都圈地区地壳最新构造变动与地震.北京:科学出版社. 许忠淮, 阎明, 赵仲和.1983.由多个小地震推断的华北地区构造应力场的方向.地震学报, 5(3):268-279. http://www.cnki.com.cn/Article/CJFDTOTAL-DZXB198303001.htm 杨歧焱, 孟立朋, 彭远黔等.2015.河北省张家口市涿鹿MS4.3级地震震害调查及地震特征分析.震灾防御技术, 10(2):353-360. doi: 10.11899/zzfy20150215 张素欣, 王晓山, 王想等.2016.2016年1月9日怀来震群序列震兆意义综合分析.华北地震科学, 34(3):32-36. http://www.cnki.com.cn/Article/CJFDTOTAL-HDKD201603007.htm 祝治平, 张先康, 张建狮等.1997.北京-怀来-丰镇剖面地壳上地幔构造与速度结构研究.地震学报, 19(5):499-505. http://www.cnki.com.cn/Article/CJFDTOTAL-DZXB705.008.htm Peng Z. G., Zhao P..2009. Migration of early aftershocks following the 2004 Parkfield earthquake. Nature Geoscience, 2(12):877-881. doi: 10.1038/ngeo697 Vidale J. E., Shearer P. M..2006. A survey of 71 earthquake bursts across southern California:exploring the role of pore fluid pressure fluctuations and aseismic slip as drivers. Journal of Geophysical Research, 111(B5):B05312. http://adsabs.harvard.edu/abs/2006JGRB..111.5312V