选取镇江市地震台RZB型分量钻孔应变仪2014年5月至2018年3月记录的全球142次地震,探讨该应变仪地震记录能力,分析震级、震中距与最大振幅之间的关系,以及地震波传播方向与四分量中振幅最大分量方位的关系。结果发现:该应变仪可记录研究时段全球发生的所有8级以上地震,理论上震级越大,记录的地震震中距越大;震级相同,震中距越大,应变仪记录的地震波最大振幅越小,拟合曲线较为符合幂函数关系;震中距相近,震级越大,应变仪记录的地震波最大振幅也越大,拟合曲线较为符合幂函数关系。偶有数据点偏离拟合曲线较远,是因为:①地震震源较深;②应变量的最大值或最小值未被记录到,量取值非实际最大和最小振幅;③有时地震波形周期难以分辨。多数地震最大振幅所在分量方向与地震传播方向基本相同。
142 global earthquakes recorded by the RZB component borehole strainmeter at Zhenjiang Seismic Station from May 2014 to March 2018 were selected to discuss the monitoring ability of the strainmeter and analyze the relationship between magnitude, epicentral distance, and maximum amplitude, as well as the relationship between the propagation direction of seismic wave and the orientation of the maximum amplitude component in four components. The results show that the strainmeter can record all earthquakes with M≥8.0 that occurred in the world during the study period. Theoretically, the larger the earthquake magnitude, the larger the epicentral distance can be recorded. For earthquakes with the same magnitude, the larger the epicentral distance, the smaller the maximum amplitude of seismic waves recorded by the strainmeter, and the fitting curve is in line with the power function relation. For earthquakes with a similar epicentral distance, the larger the magnitude, the greater the maximum amplitude of seismic waves recorded by the strainmeter, and the fitting curve is in line with the power function relation. Occasionally the recorded maximum amplitudes deviate far from the fitting curve, because:①The earthquake source is deep; ② The maximum or minimum strain values are not recorded and the measured values are not the actual maximum or minimum amplitudes; ③Sometimes the seismic waveform period is difficult to distinguish. Most earthquakes generate the maximum amplitude for the component whose direction is basically the same as the direction of seismic wave propagation.
2021,42(4): 133-138 收稿日期:2020-05-25
DOI:10.3969/j.issn.1003-3246.2021.04.017
作者简介:董晨阳(1985-),男,工程师,主要从事地震监测工作。E-mail:120109035@qq.com
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