强震动记录自适应基线校正方法:汶川地震应用
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摘要
基线校正是强震动记录数据处理非常关键的环节之一。现有方法大都依赖主观经验,得到的永久位移值存在较大的不确定性,不能实现自动化处理。为此,提出一种自适应的强震动记录基线校正方法,以汶川地震中汶川卧龙台站(051WCW)获取的强震动记录为例叙述新方法的每个环节,并与已有方法进行比较,验证了新方法的计算准确性。最后,将新方法运用于汶川地震主震中,得到了37个强震动台站的永久位移场。通过与Wang等的研究结果比较,发现除3个台站由于数据不全无法比较外,新方法给出的24个台站的最大永久位移无论是数值还是对应方位角都与其一致。表明新方法具有一定的可靠性,同时通过对比也发现新方法存在一定的局限性,还有待进一步改进。
Baseline correction is one of the most critical procedures for data processing of strong motion records. Most of the current methods depend on personal experience and cannot be automatically implemented, which results in large uncertainties of permanent displacement. In this regard, an adaptive baseline correction method for strong motion records is proposed. The strong motion records obtained at Wolong station(051 WCW) were used as an example to describe each step of the proposed method. Subsequent permanent displacement was consistent with a value provided by another method, which verified the accuracy of the proposed method. Finally, the proposed method was applied to the Wenchuan earthquake, and permanent displacement field of 37 strong motion stations was achieved. Compared to the results given by Wang, et al.(2011), this result shows that maximum permanent displacement of 24 stations given by the proposed method is almost the same as those given by the other method. The comparison indicates that the proposed method is able to correct the baseline drift in strong motion records, but has some limitations that require further improvement.
Baseline correction is one of the most critical procedures for data processing of strong motion records. Most of the current methods depend on personal experience and cannot be automatically implemented, which results in large uncertainties of permanent displacement. In this regard, an adaptive baseline correction method for strong motion records is proposed. The strong motion records obtained at Wolong station(051 WCW) were used as an example to describe each step of the proposed method. Subsequent permanent displacement was consistent with a value provided by another method, which verified the accuracy of the proposed method. Finally, the proposed method was applied to the Wenchuan earthquake, and permanent displacement field of 37 strong motion stations was achieved. Compared to the results given by Wang, et al.(2011), this result shows that maximum permanent displacement of 24 stations given by the proposed method is almost the same as those given by the other method. The comparison indicates that the proposed method is able to correct the baseline drift in strong motion records, but has some limitations that require further improvement.
引文
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[7] 王国权,周锡元.921台湾集集地震近断层强震记录的基线校正[J].地震地质,2004,26(1):1-14.WANG Guoquan,ZHOU Xiyuan.Baseline Correction of Near Fault Groundmotion Recordings of the 1999 Chi-Chi,Taiwan Earthquake[J].Seismology and Geology,2004,26(1):1-14.
[8] 荣棉水,彭艳菊,喻畑,等.近断层强震观测记录基线校正的优化方法[J].土木工程学报,2014,47(增刊2):300-306.RONG Mianshui,PENG Yanju,YU Tian,et al.Optimized Baseline Correction Method for the Near-fault Observation Strong Motion Records[J].China Civil Engineering Journal,2014,47(Supp2):300-306.
[9] 周宝峰,于海英,温瑞智,等.一种识别永久位移的新方法[J].土木工程学报,2013,46(增刊2):135-140.ZHOU Baofeng,YU Haiying,WEN Ruizhi,et al.A New Way of Permanent Displacement Identification[J].China Civil Engineering Journal,2013,46(Supp2):135-140.
[10] LI X,ZHOU Z,HUANG M,et al.Preliminary Analysis of Strong-motion Recordings from the Magnitude 8.0 Wenchuan,China,Earthquake of 12 May 2008[J].Seismological Research Letters,2008,79(6):844-854.
[2] BOORE D M.Effect of Baseline Corrections on Response Spectra for Two Recordings of the 1999 Chi-Chi Taiwan Earthquake[R].U.S.Geological Survey:Open-File Report,1999:99-545.
[3] WU Y M,WU C F.Approximate Recovery of Coseismic Deformation from Taiwan Strong-Motion Records[J].Journal of Seismology,2007,11( 2) :159-170
[4] WANG R,SCHURR B,MILKEREIT C,et al.An Improved Automatic Scheme for Empirical Baseline Correction of Digital Strong-motion Records[J].Bulletin of the Seismological Society of America,2011,101(5):2029-2044.
[5] 于海英,江汶乡,解全才,等.近场数字强震仪记录误差分析与零线校正方法[J].地震工程与工程振动,2007,29(6):1-12.YU Haiying,JIANG Wenxiang,XIE Quancai,et al.Baseline Correction of Digital Strong-motion Records in Near-field[J].Journal of Earthquake Engineering and Engineering Vibration,2007,29(6):1-12.
[6] 张培震.GPS测定的2008年汶川MS8.0级地震的同震位移场[J].中国科学D辑(地球科学),2008,38(10):1195-1206.ZHANG Peizhen.GPS Coseismic Displacements Measured in 2008 MS8.0 Wenchuan Earthquake[J].Science in China Series D (Earth Sciences),2008,38(10):1195-1206.
[7] 王国权,周锡元.921台湾集集地震近断层强震记录的基线校正[J].地震地质,2004,26(1):1-14.WANG Guoquan,ZHOU Xiyuan.Baseline Correction of Near Fault Groundmotion Recordings of the 1999 Chi-Chi,Taiwan Earthquake[J].Seismology and Geology,2004,26(1):1-14.
[8] 荣棉水,彭艳菊,喻畑,等.近断层强震观测记录基线校正的优化方法[J].土木工程学报,2014,47(增刊2):300-306.RONG Mianshui,PENG Yanju,YU Tian,et al.Optimized Baseline Correction Method for the Near-fault Observation Strong Motion Records[J].China Civil Engineering Journal,2014,47(Supp2):300-306.
[9] 周宝峰,于海英,温瑞智,等.一种识别永久位移的新方法[J].土木工程学报,2013,46(增刊2):135-140.ZHOU Baofeng,YU Haiying,WEN Ruizhi,et al.A New Way of Permanent Displacement Identification[J].China Civil Engineering Journal,2013,46(Supp2):135-140.
[10] LI X,ZHOU Z,HUANG M,et al.Preliminary Analysis of Strong-motion Recordings from the Magnitude 8.0 Wenchuan,China,Earthquake of 12 May 2008[J].Seismological Research Letters,2008,79(6):844-854.