基于Iwan两段式校正方法的原理，引入参数“时移斜率比ki”和“校正后位移的最大平坦度f”来确定强震段偏移开始时间t1和结束段偏移的开始时间t2，引入参数“均方根偏差RMSD”来选择位移末尾部分拟合函数的次数，提出了近断层强震记录基线校正的改进方法。应用该方法对芦山地震和汶川地震共8个近断层台站的强震记录进行基线校正处理获取了永久位移。结果表明，获得的永久位移与强震台站附近的GPS台站观测的同震位移吻合较好，永久位移与GPS观测结果的比在0.57~1.72，均值为0.99。在一定程度上减少了主观经验对于基线校正结果带来的不确定性。同时对比分析了7种基线校正方法对峰值地面运动参数和永久位移的影响，PGA和PGV受不同基线校正方法的影响很小，但是不同的基线校正方法对PGD和永久位移的影响非常大。
Abstract
Based on the principle of Iwan et al.’ two-stage correction method, the parameter of time shift slope ratio ki was introduced to determine starting time of strong seismic stage offset t1, and the maximum flatness of corrected displacement f was introduced to determine starting time of ending stage offset t2.The parameter of root mean square deviation RMSD was introduced to choose order number of fitted function at the end of displacement, and the improved method of baseline correction for near-fault strong ground motion records was proposed.Then this improved method was used to do baseline correction for strong seismic motion records of 8 near-fault stations of Wenchuan earthquake and Lushan one to get permanent displacements.The results showed that permanent displacements obtained agree well with the same seismic displacements measured at GPS stations close to near-fault ones, ratios of permanent displacements to GPS measured results are within the range of 0.57-1.72 and the average value is 0.99, the uncertainty brought by subjective experience to baseline correction results can be reduced to a certain extent.Meanwhile, effects of 7 baseline correction methods on peak ground motion parameters and permanent displacements were analyzed contrastively.It was shown that effects of different baseline correction methods on PGA and PGV are smaller, while those on PGD and permanent displacements are much larger.
关键词
近断层强震记录 /
基线校正 /
永久位移 /
GPS
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Key words
near-fault strong ground motion records /
baseline correction /
permanent displacement /
GPS
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参考文献
[1] Chiu H C. Stable baseline correction of digital strong-motion data [J]. Bulletin of the Seismological Society of America, 1997, 87(4): 932-944.
[2] 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 Guo-quan, ZHOU Xi-yuan. Baseline correction of near fault ground motion recordings of the 1999 Chi-chi, Taiwan earthquake [J]. Seismology and Geology, 2004, 26(1): 1-14.
[3] 彭小波. 汶川地震强震动记录分析及应用[D]. 中国地震局工程力学研究所, 2011.
PENG Xiao-bo. Analysis of strong motion recordings and its application from Wenchuan earthquake [D]. Harbin: Institute of Engineering Mechanics, China Earthquake Administration, 2011.
[4] Converse A, Brady A G. BAP: basic strong-motion accelerogram processing software, version 1.0 [M]. Virginia: US Department of the Interior, US Geological Survey, 1992.
[5] 缪惠全, 王闯, 李杰. 加速度基线漂移频域处理方法的对比研究[J]. 振动与冲击, 2016, 35(13):66-71.
MIAO Hui-quan, WANG Chuang, LI Jie. Frequency domain processing methods for accelerations baseline drift [J]. Journal of Vibration and Shock, 2016, 35(13):66-71.
[6] Iwan W D, Moser M A, Peng C Y. Some observations on strong-motion earthquake measurement using a digital accelerograph [J]. Bulletin of the Seismological Society of America, 1985, 75(5): 1225-1246.
[7] Boore D M. Effect of baseline corrections on displacements and response spectra for several recordings of the 1999 Chi-Chi, Taiwan, earthquake [J]. Bulletin of the Seismological Society of America, 2001, 91(5): 1199-1211.
[8] 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, 2009, 29(6): 1-12.
YU Hai-ying, JIANG Wen-xiang, XIE Quan-cai, et al. Baseline correction of digital strong-motion records in near-field [J]. Journal of Earthquake Engineering and Engineering Vibration, 2009, 29(6): 1-12.
[9] 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.
[10] Chao W A, Wu Y M, Zhao L. An automatic scheme for baseline correction of strong-motion records in coseismic deformation determination [J]. Journal of seismology, 2010, 14(3): 495-504.
[11] 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.
[12] 武艳强, 江在森, 王敏, 等. GPS 监测的芦山 7.0 级地震前应变积累及同震位移场初步结果[J]. 科学通报, 2013, 58(20): 1910-1916.
WU Yan-qiang, JIANG Zai-sen, Wang Min, et al. Preliminary results of the co-seismic displacement and pre-seismic strain accumulation of the Lushan MS7.0 earthquake reflected by the GPS surveying. Chin Sci Bull, 2013, 58, doi: 10.1007/s11434-013-5998-5.
[13] 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 (S2): 300-306.
RONG Mian-shui, PENG Yan-ju, YU Tian, et al. Optimized baseline correction method for the near-fault observation strong motion records [J]. China Civil Engineering Journal, 2014 (S2): 300-306.
[14] 于海英, 周宝峰, 杨程, 等. 芦山7.0 级地震及余震强震动记录初步分析[J]. 地震工程与工程振动, 2014 (S1): 153-160.
YU Hai-ying, ZHOU Bao-feng, YANG Cheng, et al. Preliminary analysis on strong motion records from the Ms7.0 Lushan earthquake and aftershocks [J]. Journal of Earthquake Engineering and Engineering Vibration, 2014 (S1): 153-160.
[15] Akkar S, Boore D M. On baseline corrections and uncertainty in response spectrafor baseline variations commonly encounteredin digital accelerograph records [J]. Bulletin of the Seismological Society of America, 2009, 99(3): 1671-1690.
[16] 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 Pei-zhen. GPS coseismic displacements measured in 2008 Ms8.0 Wenchuan earthquake [J]. Science China, 2008, 38(10):1195-1206.
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