基于振幅相对变化实现地震预警中P波的自动拾取

Automatic realization of P wave pickup in earthquake early warning with amplitude relative change

为提高地震P波初至自动拾取的抗干扰性能,提出拾取P波初至的振幅相对变化长短时均值比方法。以振幅相对变化为特征函数,其比振幅绝对变化更能突显地震波初至时刻的突变特征,利用该特征函数计算长短时均值比,减少干扰产生的地震波到时的拾取偏差。在计算特征函数前对地震波实时进行低通滤波,分别采用振幅相对变化长短时均值比方法、Allen方法、AIC准则和PAI-S/K方法,在相同干扰条件下,对160个地震拾取P波初至。研究表明,振幅相对变化长短时均值比方法拾取P波初至抗干扰能力强。该方法在考虑环境干扰、仪器干扰和地震特点基础上确定合适的阈值,可以用于地震预警。

This paper is motivated by the need for improving the anti-interference of seismic P-wave automatic pickup and proposes the method of amplitude relative change’s STA/LTA transform.The study shows that as the characteristic function,the amplitude relative change could highlight the seismic wave abrupt characteristics at the seismic wave arrival time more clearly than amplitude absolute change.The calculation of STA/LTA transform using the characteristic function could provide a reduction in the seismic wave arrival time pickup error due to interference.Picking up the P arrival times of 160 earthquakes using STA/LTA of amplitude relative change,Allen method,AIC criterion and PAI-S/K method respectively under the same interference verifies that our method has a stronger anti-interference capability.The method promises an application in earthquake early warning thanks to its ability to determine the appropriate threshold,coupled with the consideration of environmental interference,instrument interference and local earthquake characteristics.