| 吉林前郭5.8级震区上地壳速度结构 |
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| 引用本文： | 卢燕红,吴兆营,丁广,付琦,张帆.吉林前郭5.8级震区上地壳速度结构[J].吉林大学学报(地球科学版),2017(6):1894-1903. |
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| 作者姓名： | 卢燕红 吴兆营 丁广 付琦 张帆 |
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| 作者单位： | 吉林省地震局,长春,130117 |
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| 基金项目： | 吉林省科技发展计划项目，Supported by Science and Technology Development Plan of Jilin Province |
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| 摘 要： | 为了更好地研究吉林前郭地区的地震活动性,本文利用2013年10月至2015年2月吉林前郭5.8级震群周围17个地震台站记录到的405个地震事件资料,共获得2 218条P波走时数据和2 166条S波走时数据,采用地震双差层析成像技术,获取吉林前郭震区上地壳三维P波、S波速度精细结构。结果显示,震区上地壳速度分层明显,P波速度变化范围为5.8~7.2km/s,S波速度变化范围为3.4~4.0km/s,波速比(vP/vS)变化较小。震区有低速带穿过,低速带走向为北东向,倾角较大(近直立),纵向延伸至15km深度;震群主要位于低P波和S波速度区,对应较低的波速比。吉林前郭震区构造强度较低,受西太平洋板块俯冲产生应力场的影响,易于发生地震。
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| 关 键 词： | 前郭震区 双差层析成像 速度结构 上地壳 |
Upper Crustal Velocity Structure in Qianguo M5.8 Earthquake Region |
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| Abstract: | For further studying seismic activity of Qianguo in Jilin Province,we collected 405 seismic events recorded by 17 permanent and temporary stations from October 2013 to February 2015,and total 2 218 high-quality P wave arrival times and 2 166 high-quality S wave arrival times.We used doubledifference tomography method to invert the upper crust P and S wave velocity structure in Qianguo region (in the region of epicentral distance range of 0-200 km).The tomography results show that the velocity structure beneath thestudy area exhibits an obvious feature of stratification,the P wave velocity varies from 5.8 km/s to 7.2 km/s,and the S wave velocity is from 3.4 km/s to 4.0 km/s,with a small change on the vP/vs ratio.A low velocity zone beneath thestudy area is found with a trend of NE direction and a nearly vertical steep dip angle,and it extends as deep as 15 km.The earthquake cluster is located in the low P wave and low S wave velocity region corresponding to a low vP/vs ratio;so we suggest that the tectonic intensity of this region is weak,and prone toearthquake under the influence of the stress field derived from the subduction of Western Pacific slab. |
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| Keywords: | Qianguo seismic zone double-difference tomography velocity structure upper crustal |
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