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本文针对两种典型强震动加速度仪,ETNA与MR2002,利用汶川地震强余震流动观测进行了两仪器的一致性检验。通过架设在同一仪器墩上的2种强震动加速度仪在5次余震事件中所获取加速度记录的波形、峰值、傅里叶振幅谱及反应谱的对比分析可知,ETNA仪器记录的峰值加速度与MR2002仪器记录的峰值加速度间的最大相对误差达23.6%,且南北向峰值加速度差异大于东西向和竖向,竖向明显小于两水平向;反应谱及傅里叶谱变化趋势基本相同,只是幅值存在些微差异,且竖向谱値相差最小,明显小于两水平向,反应谱最大相对误差近5%,相对于低频反应谱,高频反应谱差异较大;此外,亦存在两仪器记录时程曲线反向、记录时间长度不等、触发点不同等差异。经分析认为,这些差异主要是由于两种不同仪器性能上的些微差异、仪器参数设置不同、以及触发滤波算法不同等因素引起的。
In this paper, the consistency of two typical strong motion accelerometers ETNA and MR2002, was discussed by the analysis of acceleration records from strong aftershocks of Wenchuan earthquake by means of mobile observation. Comparison of waveform, peak, Fourier amplitude spectrum and response spectrum of acceleration records obtained by 2 kinds of instrument mounted on the same pier from 5 aftershocks events showed that maximum relative error of peak acceleration between two instruments was up to 23.6%, and peak difference in the north-south direction was larger than in the east-west and vertical direction, minimum in the vertical direction; there was slight difference in response spectrum and Fourier amplitude spectrum, but minimum in the vertical direction; the maximum relative error of response spectrum was nearly 5%, compared to the low frequency response spectrum, frequency response spectrum difference was larger. In addition, there existed differences in the instrumental polarity, duration of time-history, trigger point and so on. The mechanism analysis of differences showed that these discrepancies were mainly due to the slight difference in performance and instrument parameters and triggering filtering algorithm of two strong motion accelerometers.