【摘要】 现有的地震早期预警系统大多采用宽频带记录或强震记录,然而很多地震台站仍然使用短周期地震仪.用短周期地震记录估计大地震震级时会出现饱和的现象早已众所周知.但需要研究的问题是τc和Pd方法估计地震震级时出现饱和的震级到底是多少.为研究使用短周期记录进行地震早期预警的可能性,本文使用1999年集集地震序列的强震数据(包括主震和31次余震)进行模拟实验,所选地震序列的震级在4级到7.6级范围内.用强震记录与短周期地震仪响应函数的卷积模拟短周期记录,利用其前3秒波形计算参数τc和Pd,并与用原始的强地面运动记录计算得到的结果进行比较.结果表明,在一定程度上,短周期地震记录仍可用作地震的早期阈值预警,并且Pd方法直到6.5级才出现饱和,好于τc方法.更多还原

【Abstract】 Most of the present earthquake early warning systems are based on broadband or strong motion recordings.However,the short-period instruments are still deployed.It is well-known that short-period recordings have saturation problems for large earthquakes when estimating the size of an earthquake.Thus,it is necessary to make clear the magnitude at which saturation starts to occur for the commonly used τc and Pd measurements,respectively.To investigate the possibility of using short-period seismic recordings for earthquake early warning,we conducted a simulated experiment using the strong motion data of the 1999 Jiji(Chi-Chi)earthquake sequence including its main shock and 31 aftershocks,with magnitude span from 4 to 7.6.The strong motion acceleration recordings were convolved with the instrument response of short-period seismographs in North China to simulate short-period recordings.Parameters τc and Pd from the first-three-second seismograms were calculated for the simulated short-period recordings and compared with that obtained by the original strong ground motion recordings.The result showed that to some extent,short-period recordings can be used for threshold earthquake early warning,while the magnitude saturation of Pd estimation can be up to 6.5,better than τc estimation.更多还原