2013年7月22日岷县漳县6.6级地震强震记录及特征分析
|
摘要
2013年7月22日甘肃省定西市岷县漳县交界发生6.6级地震,国家强震动台网在甘肃、四川和陕西的64台强震仪触发并获得了主震加速度记录。本文对强震动记录进行了常规处理,统计了强震动记录数量随震中距的分布,绘制了空间地震动加速度等值线图;通过观测数据与霍俊荣和意大利新一代地震动衰减公式对比,分析了峰值加速度(PGA)及谱加速度衰减关系,发现此次地震观测数值远低于常用地震动预测值;利用渭河盆地的远场记录验证了远场地震动卓越周期变大的特点以及场地对记录的影响;参考岷县地区地质特点并通过分析宏观烈度及地震动的谱烈度,初步确定了地震震害与烈度的相关性。
The Minxian-Zhangxian MS6.6 earthquake occurred on July 22,2013,at Minxian country,Gansu province(34.5°N,104.2°E),which had resulted in 95persons dead and 1366persons injured until July 24,2013.Digital strong ground motion records of high quality have been obtained in this earthquake for the third time in China following the Wenchuan earthquake and the Lushan earthquake.64strong motion stations installed in Gansu,Sichuan and Shanxi province were triggered and acceleration records in the main shock were obtained.In this paper,the preliminary characteristics of these records were analyzed including the spatial locations of these stations,the number of records within different epicenter distances and PGA contours.Comparing the observed data with the attenuation relationship(ground motion prediction equations:one is HUO(1989)and another one is Italy08),it has been found that the observed PGAs and spectral accelerations are remarkably lower than the empirically predicted ones.In general,the far-field strong ground motion is much lower;however,long-period ground motion attenuates slower than the near-field ground motion due to the particular traveling path and site effect.The reason of the amplification is that some stations located in the center of the basin have a thick overburden than the station located at the edge of the basin.The analysis of the far-field records obtained in Weihe Basin indicates the predominant period become longer.Housner G W proposed IH as an effective intensity measure to correlate seismic severity with structural damage to buildings.For this reason,records and code values have also been compared in terms of IH.By analyzing the Macro seismic intensity and Housner spectral intensity and consulting the geological characteristics of Minxian,the good correlation between the earthquake damage and seismic intensity has been preliminarily presented.Because of the economic backwardness,the houses in rural areas are mainly of masonry structures,of which the seismic performance is poor.Many houses are severely damaged in the earthquake,especially the houses near the epicenter in Minxian country.Most of them are sited in poor geological region,such as valleys,steep slopes and hills.What's more,the slope effect amplifies the effect,so the houses are damaged more seriously.The original structure of loess looses because of the ground motion,and then led to the landslides.So the Minxian-Zhangxian earthquake was not very strong,but the earthquake also caused a lot of geological disasters.The macro intensity of China has the characteristics of integrated indicators.This study has an important role on ground motion characteristics and engineering damage investigation in the western region of China.Strong motion records in MinxianZhangxian earthquake can be used in further study of ground motion characteristics by combining with that in the Wenchuan earthquake and Lushan earthquake.
The Minxian-Zhangxian MS6.6 earthquake occurred on July 22,2013,at Minxian country,Gansu province(34.5°N,104.2°E),which had resulted in 95persons dead and 1366persons injured until July 24,2013.Digital strong ground motion records of high quality have been obtained in this earthquake for the third time in China following the Wenchuan earthquake and the Lushan earthquake.64strong motion stations installed in Gansu,Sichuan and Shanxi province were triggered and acceleration records in the main shock were obtained.In this paper,the preliminary characteristics of these records were analyzed including the spatial locations of these stations,the number of records within different epicenter distances and PGA contours.Comparing the observed data with the attenuation relationship(ground motion prediction equations:one is HUO(1989)and another one is Italy08),it has been found that the observed PGAs and spectral accelerations are remarkably lower than the empirically predicted ones.In general,the far-field strong ground motion is much lower;however,long-period ground motion attenuates slower than the near-field ground motion due to the particular traveling path and site effect.The reason of the amplification is that some stations located in the center of the basin have a thick overburden than the station located at the edge of the basin.The analysis of the far-field records obtained in Weihe Basin indicates the predominant period become longer.Housner G W proposed IH as an effective intensity measure to correlate seismic severity with structural damage to buildings.For this reason,records and code values have also been compared in terms of IH.By analyzing the Macro seismic intensity and Housner spectral intensity and consulting the geological characteristics of Minxian,the good correlation between the earthquake damage and seismic intensity has been preliminarily presented.Because of the economic backwardness,the houses in rural areas are mainly of masonry structures,of which the seismic performance is poor.Many houses are severely damaged in the earthquake,especially the houses near the epicenter in Minxian country.Most of them are sited in poor geological region,such as valleys,steep slopes and hills.What's more,the slope effect amplifies the effect,so the houses are damaged more seriously.The original structure of loess looses because of the ground motion,and then led to the landslides.So the Minxian-Zhangxian earthquake was not very strong,but the earthquake also caused a lot of geological disasters.The macro intensity of China has the characteristics of integrated indicators.This study has an important role on ground motion characteristics and engineering damage investigation in the western region of China.Strong motion records in MinxianZhangxian earthquake can be used in further study of ground motion characteristics by combining with that in the Wenchuan earthquake and Lushan earthquake.
引文
[1]Li Xiao-jun,Zhou Zheng-hua,Yu Hai-ying,et al.Strong motion Observations and Recordings from the Great Wenchuan Earthquake[J].Earthquake Engineering and Engineering Vibration,2008,7(3):235-246.
[2]任叶飞,温瑞智,周宝峰,等.2013年4月20日四川芦山地震强地面运动三要素特征分析[J].地球物理学报,(待刊).REN Ye-fei,WEN Rui-zhi,ZHOU Bao-feng,et al.The Characteristics of Strong Ground Motion of Lushan Earthquake on April 20,2013[J].Chinese Journal of geophysics,(Accepted).(in Chinese)
[3]温瑞智,任叶飞,黄旭涛,等.芦山7.0级地震强震动记录及其震害相关性[J].地震工程与工程振动,2013,33(4):1-14.WEN Rui-zhi,REN Ye-fei,HUANG Xu-tao,et al.Strong Motion Recordings in Lushan Earthquake on April 20,2013[J].Journal of Earthquake Engineering and Engineering Vibration,2013,33(4):1-14.(in Chinese)
[4]Boore D M.Effect of Baseline Corrections on Displacements and Response Spectra for Several Recordings of the 1999Chi-Chi,Taiwan[J].Bulletin of the Seismological Society of America,2001,91(5):1199-1211.
[5]霍俊荣.近场强地面运动衰减规律的研究[D].哈尔滨:国家地震局工程力学研究所,1989.HUO Jun-rong.Study on Attenuation Laws of Strong Earthquake Ground Motion near the Ssource[D].Harbin:Institute of Engineering Mechanics,China Earthquake Administration,1989.(in Chinese)
[6]中华人民共和国国家标准.中国地震烈度表(GB/T17742)[S].2008.Standard of Peoples Republic of China.The Chinese Seismic Intensity Scale(GB/T17742-2008)[S].2008.(in Chinese)
[7]Housner G W.Intensity of Ground Motion during Strong Earthquakes[R].Pasadena,California:California Institute of Technology,1952.
[8]Masi A,Chiauzzi L,Braga F,et al.Peak and Integral Seismic Parameters of L'Aquila 2009Ground Motions:Observed Versus Code Provision values[J].Bulletin of Earthquake Engineering,2011,(9):139-156.
[9]石玉成,王兰民,张颖.黄土场地覆盖层厚度和地形条件对地震动放大效应的影响[J].西北地震学报,1999,22(2):203-208.SHI Yu-cheng,WANG Lan-min,ZHANG Ying.Effects of Overburden Thickness and Topography of Loessial Sites on Earthquake Ground Motion[J].Northwestern Seismological Journal,1999,22(2):203-208.(in Chinese)
[11]才树华,王兰民,袁中夏.陕甘宁晋地区黄土地震滑坡致灾距的初步研究[J].西北地震学报,1998,20(4):75-82.CAI Shu-hua,WANG Lan-min,YUAN Zhong-xia.A Preliminary Study on the Seismic Landside Distance in the Shaanxi-Gansu-Ningxia-Shanxi Loess Region[J].Northwestern Seismological Journal,1998,20(4):75-82.(in Chinese)
[2]任叶飞,温瑞智,周宝峰,等.2013年4月20日四川芦山地震强地面运动三要素特征分析[J].地球物理学报,(待刊).REN Ye-fei,WEN Rui-zhi,ZHOU Bao-feng,et al.The Characteristics of Strong Ground Motion of Lushan Earthquake on April 20,2013[J].Chinese Journal of geophysics,(Accepted).(in Chinese)
[3]温瑞智,任叶飞,黄旭涛,等.芦山7.0级地震强震动记录及其震害相关性[J].地震工程与工程振动,2013,33(4):1-14.WEN Rui-zhi,REN Ye-fei,HUANG Xu-tao,et al.Strong Motion Recordings in Lushan Earthquake on April 20,2013[J].Journal of Earthquake Engineering and Engineering Vibration,2013,33(4):1-14.(in Chinese)
[4]Boore D M.Effect of Baseline Corrections on Displacements and Response Spectra for Several Recordings of the 1999Chi-Chi,Taiwan[J].Bulletin of the Seismological Society of America,2001,91(5):1199-1211.
[5]霍俊荣.近场强地面运动衰减规律的研究[D].哈尔滨:国家地震局工程力学研究所,1989.HUO Jun-rong.Study on Attenuation Laws of Strong Earthquake Ground Motion near the Ssource[D].Harbin:Institute of Engineering Mechanics,China Earthquake Administration,1989.(in Chinese)
[6]中华人民共和国国家标准.中国地震烈度表(GB/T17742)[S].2008.Standard of Peoples Republic of China.The Chinese Seismic Intensity Scale(GB/T17742-2008)[S].2008.(in Chinese)
[7]Housner G W.Intensity of Ground Motion during Strong Earthquakes[R].Pasadena,California:California Institute of Technology,1952.
[8]Masi A,Chiauzzi L,Braga F,et al.Peak and Integral Seismic Parameters of L'Aquila 2009Ground Motions:Observed Versus Code Provision values[J].Bulletin of Earthquake Engineering,2011,(9):139-156.
[9]石玉成,王兰民,张颖.黄土场地覆盖层厚度和地形条件对地震动放大效应的影响[J].西北地震学报,1999,22(2):203-208.SHI Yu-cheng,WANG Lan-min,ZHANG Ying.Effects of Overburden Thickness and Topography of Loessial Sites on Earthquake Ground Motion[J].Northwestern Seismological Journal,1999,22(2):203-208.(in Chinese)
[11]才树华,王兰民,袁中夏.陕甘宁晋地区黄土地震滑坡致灾距的初步研究[J].西北地震学报,1998,20(4):75-82.CAI Shu-hua,WANG Lan-min,YUAN Zhong-xia.A Preliminary Study on the Seismic Landside Distance in the Shaanxi-Gansu-Ningxia-Shanxi Loess Region[J].Northwestern Seismological Journal,1998,20(4):75-82.(in Chinese)
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心