地震研究

利用Pn-Pg震相组合的局部搜索法,采用5种地壳速度模型对2013年吉林前郭5.8级地震震群进行震源深度测定。计算结果显示,5种结果的震源深度的主要分布特征相似。对选取的32个地震震源深度进行重新测定,结果最小为6 km,最大14 km,主要集中在10 km左右,系统深度偏差约1.74 km,震源深度分辨率约1.58 km,重定位后地震震中优势分布呈北西向。与当地的沉积层厚度分布对比,这些地震最有可能发生在盆地基底的基岩顶层,而不在油气圈闭的沉积盖层内,并且地震震群分布走向与通榆—长春断裂走向相一致。结合该地区的历史地震活动与构造关系,最后推测这些地震与北西向的通榆—长春断裂构造运动密切相关,而不是油田作业的直接产物。

Using the local optimum search strategy of couple Pn-Pg phases algorithms,we determined the focal depth of Jilin Qianguo M_S5.8 earthquake sequence in 2013 by five different curst velocity models,and the calculation results indicate that the distribution characteristic of the 5 kinds of focal depth is consistency. The focal depths of the selected 32 earthquakes are relocated,the minimum and maximum focal depths are 6 km and 14 km respectively,most focal depths focus on 10 km. The systemic depth measure error may be 1.74 km,and the resolution of focal depth may be about 1.58 km. The advantage distribution of the relocated epicenters is in the NW direction. Compared with the thickness of local sedimentation in the study area,these earthquakes most probably occurred at the top of bed rock under the basin basement,rather than at the sediment overlying strata of oil field. Moreover,the preponderance direction of the distribution of these epicenters is consistent with the strike of Tongyu-Changchun Fault. Combined with the relationship between the local historical earthquakes and tectonic in the study area,we take a further speculation that the earthquake sequence maybe related with the tectonic activity of Tongyu-Changchun Fault in NW,rather than the direct production of the oil-field operation.

引言
1 区域构造特征及Pn-Pg局部搜索法
2 前郭震群的地震深度测定及其精度分析
3 认识与结论

表1 不同震中距不同深度时的灵敏度κ分布<br/>Tab.1 Distribution of sensitivity κ in different epicenter distance and focal depth

表1 不同震中距不同深度时的灵敏度κ分布
Tab.1 Distribution of sensitivity κ in different epicenter distance and focal depth

图1 2013年12月8日前郭MS3.1地震震中分布(a)及局部放大图(b)<br/>Fig.1 Epicenter distribution of Qianguo MS3.1 earthquake on Dec.8,2013(a)and the partial enlarged drawing of dotted rectangle in Fig.1a(b)

图1 2013年12月8日前郭MS3.1地震震中分布(a)及局部放大图(b)
Fig.1 Epicenter distribution of Qianguo MS3.1 earthquake on Dec.8,2013(a)and the partial enlarged drawing of dotted rectangle in Fig.1a(b)

图2 2013年12月8日前郭MS3.1地震走时残差空间切片图<br/>(a)震中区局部网格的走时残差三维切片;(b)沿原震中位置和沿最小值点处的不同深度残差曲线<br/>Fig.2 Slice of travel time residuals of Qianguo MS3.1 earthquake on Dec.8,2013 (a)3D slice of travel time residual in local calculation nodes in the epicenter area;(b)residual changes in different depth at the positions of initialized epicenter and with minimum travel-time residual

图2 2013年12月8日前郭MS3.1地震走时残差空间切片图
(a)震中区局部网格的走时残差三维切片;(b)沿原震中位置和沿最小值点处的不同深度残差曲线
Fig.2 Slice of travel time residuals of Qianguo MS3.1 earthquake on Dec.8,2013 (a)3D slice of travel time residual in local calculation nodes in the epicenter area;(b)residual changes in different depth at the positions of initialized epicenter and with minimum travel-time residual

表2 本文采用的地壳P波速度模型<br/>Tab.2 P-wave crustal velocity model used in this paper

表2 本文采用的地壳P波速度模型
Tab.2 P-wave crustal velocity model used in this paper

表3 3种定位的结果对比<br/>Tab.3 Comparison of three location results

表3 3种定位的结果对比
Tab.3 Comparison of three location results

图3 震相走时—震中距散点分布<br/>Fig.3 Scatter distribution diagram of phase travel time varied with distance

图3 震相走时—震中距散点分布
Fig.3 Scatter distribution diagram of phase travel time varied with distance

图4 地壳速度模型深度变化曲线<br/>Fig.4 Curve of depth change of crustal velocity models

图4 地壳速度模型深度变化曲线
Fig.4 Curve of depth change of crustal velocity models

图5 不同速度模型给出的32个地震震源深度分布(a)、走时残差分布(b)与深度测定的Pn-Pg对数(c)<br/>Fig.5 Distribution of focal depth(a)and travel-time residual(b),and logarithms of Pn-Pg determined by depth(c)of 32 earthquakes in different velocity model

图5 不同速度模型给出的32个地震震源深度分布(a)、走时残差分布(b)与深度测定的Pn-Pg对数(c)
Fig.5 Distribution of focal depth(a)and travel-time residual(b),and logarithms of Pn-Pg determined by depth(c)of 32 earthquakes in different velocity model

图6 不同速度模型给出的32个地震震源深度及震中分布(图号与模型号对应)<br/>Fig.6 Distributions of focal depth and epicenter of 32 earthquakes in different velocity model (figure munber corresponds with the number of velocity model)

图6 不同速度模型给出的32个地震震源深度及震中分布(图号与模型号对应)
Fig.6 Distributions of focal depth and epicenter of 32 earthquakes in different velocity model (figure munber corresponds with the number of velocity model)

图7 流动台L2202记录三组地震的波形(a～c)及台站与震中位置(a'～c'); <br/>Fig.7 Waveforms of three pairs of earthquakes recorded by mobile seismic station of L2202 (a～c)and distribution of the location of station and epicenter(a'～c');

图7 流动台L2202记录三组地震的波形(a～c)及台站与震中位置(a'～c');
Fig.7 Waveforms of three pairs of earthquakes recorded by mobile seismic station of L2202 (a～c)and distribution of the location of station and epicenter(a'～c');

程学儒.1982.松辽盆地的板块构造位置与烃类产出特征[J].石油勘探与开发,(6):39-48.
傅淑芳,刘宝诚.1980.地震学教程[M].北京:地震出版社,185-188.
傅维洲,刘宝俊,刘财,等.1998.中国满洲里—绥芬河地学断面地震学研究[J].长春科技大学学报,28(2):206-212.
高金哲,李志伟,包丰,等.2013.2006年吉林乾安—前郭5.0级地震深度及其成因探讨[J].地球物理学进展,28(5):2328-2335.
胡望水,吕炳全,张文军,等.2005.松辽盆地构造演化及成盆动力学探讨[J].地质科学,40(1):16-31.
刘天革,隋红.1985.东北地区北西向构造与地震[C]//国家地震局地质研究所.遥感地震地质文集,北京:地震出版社,1-9.
刘洋,刘财,杨宝俊,等.2008.松辽盆地北部纵波速度区域特征分析及深层油气问题[J].地球物理学进展,23(3):785-792.
刘元生,王六桥.1985.油井动态与地震关系研究的新进展[J].华北地震科学,3(1):1-5.
盘晓东,王军亮,孙旭丽,等.2007.乾安—前郭5.0级地震的构造背景分析[J].东北地震研究,23(1):8-15.
祁林,韩广林,张惠.1992.松辽盆地喜山运动期地应力场演化对油气运聚的影响[J].石油与天然气地质,13(4):398-407.
裘善文,王锡魁,张淑芹,等.2012.松辽平原古大湖演变及其平原的形成[J].第四纪研究,32(5):1011-1021.
唐雅芝.1990.公元1119年2月吉林省前郭强震三要素的确定[J].东北师大学报(自然科学版),(3):152-160.
滕吉文,曾融生.2002.东亚大陆及周边海域Moho界面深度分布和基本构造格局[J].中国科学(D辑),32(2):89-100.
杨宝俊,唐建人,李勤学,等.2003.松辽盆地隆起区地壳反射结构与“断开”莫霍界面[J].中国科学(D辑),33(2):170-176.
杨令宾.1995.松辽平原的生成与演化[J].东北师大学报(自然科学版),(2):119-124.
周本刚,高名修.1992.松辽盆地几次中强震的构造条件探讨[J].地震地质,14(2):145-150.
朱元清,石耀霖.1990.一种确定地震深度的新方法[J].地震地磁观测与研究,11(2):4-12.
中国地震局地球物理研究所.2013a. 2013年10月31日吉林省松原市前郭尔罗斯蒙古族自治县5.5级地震[EB/OL].(2013-10-31)[2014-04-27].http://www.cea-igp.ac.cn/tpxw/267882.shtml.
中国地震局地球物理研究所.2013b. 2013年11月23日吉林省松原市前郭尔罗斯蒙古族自治县5.8级、5.0级地震[EB/OL].(2013-11-23)[2014-04-27].http://www.cea-igp.ac.cn/tpxw/267992.shtml.
Davis D.S.,Nyffenegger P.A.,Frohlich C..1995.The 9 April 1993 earthquake in south-central texas:Was it induced by fluid withdrawal[J].Bull.Seism.Soc.Am.,85(6):1888-1895.

备注

引言

1 区域构造特征及Pn-Pg局部搜索法

2 前郭震群的地震深度测定及其精度分析

3 认识与结论

期刊信息