汶川8.0级地震强震动特征初步分析
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摘要
本文对国家强震动台网中心收集的2008年5月12日14时28分04秒汶川8.0级地震中获取的420组三分量加速度记录进行了处理和初步分析。在这次地震中布设在龙门山断裂带及其周围地区的50多个台站获得了大于100gal的加速度记录,有46组三分量加速度记录的断层距小于100km,使中国大陆近断层区域所获得的强震动加速度记录的数量成倍增加。本文依据这批数据,对汶川大地震强震动特性进行了初步分析,给出了此次地震断层附近地区的PGA衰减规律,并利用此规律模拟了断层附近的加速度峰值,绘制了PGA分布图、竖向PGA与水平向PGA比值图;给出了汶川地震断层附近的加速度反应谱、上盘效应、竖向效应、速度大脉冲效应等地震动特征,这些特征可作为抗震设计规范修订的依据并供灾区重建时参考。
In this paper,a total of 420 three-component acceleration records obtained from the MS8.0 Wenchuan earthquake which struck Sichuan,China on May 12th,2008 at 14:28:04 were processed and analyzed preliminarily.All records were collected by China Strong Motion Net Center(CSMNC).There are more than 50 stations set up along Longmenshan mountain fault zone and acceleration record is as high as over 100 gals,in which 46 three-component acceleration records were collected within in the distance of less than 100 km from the fault.Amount of near-fault strong motion records in Mainland China greatly increase.Based on the collected data,the basic characteristics of the strong ground motion of Wenchuan earthquake were analyzed.Based on the statistical analysis of PGA,the specific attenuation of Wenchuan earthquake is obtained,and this attenuation relationship is then applied to simulate near-fault PGA of the region.The spatial distributions of PGA and the ratio between the vertical and horizontal acceleration are plotted.The basic characteristics of near-fault ground motion of this earthquake,such as acceleration response spectrum,the hanging wall effect,the vertical effect,the rupture directivity effect,the fling step effect can be used as reference in the seismic design code recension and disaster area reconstruction.
In this paper,a total of 420 three-component acceleration records obtained from the MS8.0 Wenchuan earthquake which struck Sichuan,China on May 12th,2008 at 14:28:04 were processed and analyzed preliminarily.All records were collected by China Strong Motion Net Center(CSMNC).There are more than 50 stations set up along Longmenshan mountain fault zone and acceleration record is as high as over 100 gals,in which 46 three-component acceleration records were collected within in the distance of less than 100 km from the fault.Amount of near-fault strong motion records in Mainland China greatly increase.Based on the collected data,the basic characteristics of the strong ground motion of Wenchuan earthquake were analyzed.Based on the statistical analysis of PGA,the specific attenuation of Wenchuan earthquake is obtained,and this attenuation relationship is then applied to simulate near-fault PGA of the region.The spatial distributions of PGA and the ratio between the vertical and horizontal acceleration are plotted.The basic characteristics of near-fault ground motion of this earthquake,such as acceleration response spectrum,the hanging wall effect,the vertical effect,the rupture directivity effect,the fling step effect can be used as reference in the seismic design code recension and disaster area reconstruction.
引文
陈运泰,许力生等,2008.2008年5月12日汶川特大地震震源特性分析报告.中国地震局地球物理研究所网站,汶川8.0级地震抗震救灾科技专题报道.
李小军,周正华,于海英,温瑞智,2008.汶川8.0级地震强震动观测及记录初步分析.见:汶川地震建筑震害分析与重建研讨会论文集,28—29.
李政宽,罗俊雄,辛在勤,1999.集集地震之地震观测及强地动分析.结构工程,14(3):5—28.
中国地震局震害防御司,2008.汶川8.0级地震未校正加速度记录.中国强震记录汇报,第十二集,第一卷,北京:地震出版社.
Chen Ji and Gavin Hayes,2008.Finite Fault Model—Preliminary Result of the May12,2008MW7.9Eastern Sichuan,China Earthquake.The Web of National Earthquake Information Center(NEIC)of United States Geological Survey.
李小军,周正华,于海英,温瑞智,2008.汶川8.0级地震强震动观测及记录初步分析.见:汶川地震建筑震害分析与重建研讨会论文集,28—29.
李政宽,罗俊雄,辛在勤,1999.集集地震之地震观测及强地动分析.结构工程,14(3):5—28.
中国地震局震害防御司,2008.汶川8.0级地震未校正加速度记录.中国强震记录汇报,第十二集,第一卷,北京:地震出版社.
Chen Ji and Gavin Hayes,2008.Finite Fault Model—Preliminary Result of the May12,2008MW7.9Eastern Sichuan,China Earthquake.The Web of National Earthquake Information Center(NEIC)of United States Geological Survey.
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