A M_L3.8 earthquake occurred on February 23,2014 in Rongchang County,which is located at the southern edge of the Sichuan Basin in the border area between Sichuan and Chongqing. This paper presents results of focal me...A M_L3.8 earthquake occurred on February 23,2014 in Rongchang County,which is located at the southern edge of the Sichuan Basin in the border area between Sichuan and Chongqing. This paper presents results of focal mechanism solution of this earthquake using the CAP( cut and paste) method based on broadband seismograms recorded by regional seismic stations. Our results show that the moment magnitude is M_W3. 09 and focal depth is 3km. The hypocenter of this earthquake is located close to a buried fault in the Luoguangshan anticline. Oil prospecting and deep drilling data indicate that this buried fault is a thrust fault,striking SW230°,dipping NW45°,and 1. 7km deep. There are some injection wells within the anticline,and significant injection-induced earthquakes were observed during the periods of injection of waste water into the deep formations through those wells. The best double couple solution of the M_L3.8 earthquake is 247°,48°and 104° for strike,dip and rate,respectively,for one nodal plane( and 46°,44° and 74°for another nodal plane),which is in agreement with the geometry of the buried fault.Therefore,we conclude that the M_L3.8 Rongchang earthquake is possibly the result of faulting along the buried reverse fault induced by water injection under the compressive stress regime in the area.展开更多
In this article, we have inverted local broadband waveform data to determine the focal mechanism of the 2011 MS4.8 Anqing earthquake. Our results show that the best double couple solution of the MS4.8 event is 16°...In this article, we have inverted local broadband waveform data to determine the focal mechanism of the 2011 MS4.8 Anqing earthquake. Our results show that the best double couple solution of the MS4.8 event is 16°, 74° and 120° for strike, dip and rake angles of one nodal plane respectively, and 131°, 33°, 30° for the other nodal plane. The estimated focal depth is about 3km. Both strikes of the two nodal planes differ significantly to the strike of Susong-Zongyang fault, along which seismic activity has been at a low level since the Late Quaternary. This implies that this earthquake may not have occurred on the Susong-Zongyang fault, and we infer that a buried fault with strike of NNE may be the seismogenic structure of this event.展开更多
利用湖北与重庆区域台网共9个台的宽频带数字地震记录,采用CAP法(Cut and Paste Method)反演了湖北巴东2013年12月16日MS5.1地震震源机制解,其最佳双力偶解为节面I:走向166°,倾角82°,滑动角41°;节面Ⅱ:走向69°,倾角...利用湖北与重庆区域台网共9个台的宽频带数字地震记录,采用CAP法(Cut and Paste Method)反演了湖北巴东2013年12月16日MS5.1地震震源机制解,其最佳双力偶解为节面I:走向166°,倾角82°,滑动角41°;节面Ⅱ:走向69°,倾角49°,滑动角169°;最佳震源深度主要集中分布在5.5km附近。分析认为此次地震的发震断层为带有逆冲成分的走滑性质断层,主压应力P轴近EW向,主张应力轴近NS向。余震序列主要呈EW分布,少部分呈NS方向分布,较大余震的发震破裂滑动类型以正走滑型的居多,其次为逆倾滑型及逆走滑型。结合7次较大余震的机制解判断,近EW向节面为发震断层。展开更多
利用来源于湖北区域台网共6个台的宽频带数字地震记录,采用CAP法(Cut and Paste Method)反演了2008年11月22日湖北-秭归Ms4.1级地震和09月27日Ms3.2中小震的震源机制解。结果显示,2次地震的震源机制解有一些差别,但是均为逆冲兼走滑分...利用来源于湖北区域台网共6个台的宽频带数字地震记录,采用CAP法(Cut and Paste Method)反演了2008年11月22日湖北-秭归Ms4.1级地震和09月27日Ms3.2中小震的震源机制解。结果显示,2次地震的震源机制解有一些差别,但是均为逆冲兼走滑分量性质断层,主压应力P轴主要集中在NE向,与区域主压应力方向有一定一致性。分析认为秭归地震可能是仙女山断裂受库水渗透和载荷变化影响引发的水库构造地震。通过与P波初动地震震源机制结果对比发现,该地震的震源机制的反演结果有较好的一致性,结果较可信。展开更多
基于Cut And Paste(CAP)全波形拟合反演震源机制解方法,依托中国地震局地震预测研究所准实时地震波形数据服务系统,通过接收区域实时连续波形数据,构建了首都圈地区准实时准自动波形反演系统,使系统实现当地震大于3.5级时,可自动、迅速...基于Cut And Paste(CAP)全波形拟合反演震源机制解方法,依托中国地震局地震预测研究所准实时地震波形数据服务系统,通过接收区域实时连续波形数据,构建了首都圈地区准实时准自动波形反演系统,使系统实现当地震大于3.5级时,可自动、迅速反演得到震源机制解。同时考虑到一些台站的地震波形质量或信噪比等因素,系统也可通过人为干预方式重新反演求得相关结果。文中详细阐述了震源机制解波形反演系统的运行流程及该系统的基本构建思路,并对实例进行对比分析,表明该系统具有较好的实用性。展开更多
基金funded jointly by the Scitech R&D Program of Chongqing Municipality(cstc2014yykfA00002(cstc2014yykfA0234),cstc2014jccxA0028 and cstc2013ggB0011)the Spark Program of Earthquake Sciences of CEA(Grant No.XH14042)
文摘A M_L3.8 earthquake occurred on February 23,2014 in Rongchang County,which is located at the southern edge of the Sichuan Basin in the border area between Sichuan and Chongqing. This paper presents results of focal mechanism solution of this earthquake using the CAP( cut and paste) method based on broadband seismograms recorded by regional seismic stations. Our results show that the moment magnitude is M_W3. 09 and focal depth is 3km. The hypocenter of this earthquake is located close to a buried fault in the Luoguangshan anticline. Oil prospecting and deep drilling data indicate that this buried fault is a thrust fault,striking SW230°,dipping NW45°,and 1. 7km deep. There are some injection wells within the anticline,and significant injection-induced earthquakes were observed during the periods of injection of waste water into the deep formations through those wells. The best double couple solution of the M_L3.8 earthquake is 247°,48°and 104° for strike,dip and rate,respectively,for one nodal plane( and 46°,44° and 74°for another nodal plane),which is in agreement with the geometry of the buried fault.Therefore,we conclude that the M_L3.8 Rongchang earthquake is possibly the result of faulting along the buried reverse fault induced by water injection under the compressive stress regime in the area.
基金supported by the China Earthquake Administration as a work Assignment for Seismic Situation Tracing for Earthquake Forecast and Prediction (2011020104)
文摘In this article, we have inverted local broadband waveform data to determine the focal mechanism of the 2011 MS4.8 Anqing earthquake. Our results show that the best double couple solution of the MS4.8 event is 16°, 74° and 120° for strike, dip and rake angles of one nodal plane respectively, and 131°, 33°, 30° for the other nodal plane. The estimated focal depth is about 3km. Both strikes of the two nodal planes differ significantly to the strike of Susong-Zongyang fault, along which seismic activity has been at a low level since the Late Quaternary. This implies that this earthquake may not have occurred on the Susong-Zongyang fault, and we infer that a buried fault with strike of NNE may be the seismogenic structure of this event.
文摘利用湖北与重庆区域台网共9个台的宽频带数字地震记录,采用CAP法(Cut and Paste Method)反演了湖北巴东2013年12月16日MS5.1地震震源机制解,其最佳双力偶解为节面I:走向166°,倾角82°,滑动角41°;节面Ⅱ:走向69°,倾角49°,滑动角169°;最佳震源深度主要集中分布在5.5km附近。分析认为此次地震的发震断层为带有逆冲成分的走滑性质断层,主压应力P轴近EW向,主张应力轴近NS向。余震序列主要呈EW分布,少部分呈NS方向分布,较大余震的发震破裂滑动类型以正走滑型的居多,其次为逆倾滑型及逆走滑型。结合7次较大余震的机制解判断,近EW向节面为发震断层。
文摘利用来源于湖北区域台网共6个台的宽频带数字地震记录,采用CAP法(Cut and Paste Method)反演了2008年11月22日湖北-秭归Ms4.1级地震和09月27日Ms3.2中小震的震源机制解。结果显示,2次地震的震源机制解有一些差别,但是均为逆冲兼走滑分量性质断层,主压应力P轴主要集中在NE向,与区域主压应力方向有一定一致性。分析认为秭归地震可能是仙女山断裂受库水渗透和载荷变化影响引发的水库构造地震。通过与P波初动地震震源机制结果对比发现,该地震的震源机制的反演结果有较好的一致性,结果较可信。
文摘基于Cut And Paste(CAP)全波形拟合反演震源机制解方法,依托中国地震局地震预测研究所准实时地震波形数据服务系统,通过接收区域实时连续波形数据,构建了首都圈地区准实时准自动波形反演系统,使系统实现当地震大于3.5级时,可自动、迅速反演得到震源机制解。同时考虑到一些台站的地震波形质量或信噪比等因素,系统也可通过人为干预方式重新反演求得相关结果。文中详细阐述了震源机制解波形反演系统的运行流程及该系统的基本构建思路,并对实例进行对比分析,表明该系统具有较好的实用性。
