高速列车移动震源地震记录

Seismic records of high speed train

地球上的环境噪声作为被动震源已被用于地球内部结构研究,在地球科学与工程方面取得了良好的应用效果.随着人类活动频繁加剧,由移动交通工具产生的交通噪声,已经成为一种特别需要关注的环境噪声被动震源.高速运行列车产生的交通噪声,相比其他交通噪声能量强,连续稳定,并且具有可重复性,特别是近十几年来,中国高速铁路发展迅速,形成了覆盖中国大陆的高速铁路网络,为大范围、长期观测高速列车产生的交通噪声并研究其应用提供了基础.我们利用地震勘探检波器,分别采集高速列车运行产生的地震记录以及相同位置无高速列车运行的环境噪声,对地震记录信号以及环境噪声进行了频谱分析以及地震波干涉等处理.频谱分析结果显示,高速列车运行产生的地震信号能量约是环境噪声能量的10~3倍,而地震信号频率成分与高速列车运行速度相关.我们分别对高速列车运行产生的地震信号与环境噪声进行了地震波干涉处理,重建出地震初至波以及续至波信息,经过初步分析,重建的初至波地震波场揭示了地表地震波传播特征,而续至波波场十分复杂.高速列车作为一种移动被动震源产生的地震记录具有应用潜力.

Traffic noise,as a typical passive source,can be used for scientific research or engineering applications such as the study of the internal structure of Earth,or the urban underground survey.Nowadays,however,as China high-speed railways showed a great potential to be a reliable kind of source for passive-source seismic prospecting with its wide distribution,the stronger energy,and the repeatability,it is possible for the long-term observation and study of this kind of traffic noise.This research focuses on the potential application of seismic records of high-speed trains,and the differences between this kind of signals and that generated by general traffic noise.Here we report an experiment of seismic records generated by high-speed trains,as well as by other ambient noise.By amplitude spectrum analysis and Seismic Interferometry(SI),we find that the energy level of seismic signals from highspeed-running trains are much higher than that from ambient noise,and the spectrum of seismic records from high speed railway is predominated by the speed of trains.According to our preliminary analysis of the reconstructed seismic records by seismic interferometry,the direct waves reveal the features of surface seismic wave propagation,which can be used to image the earth interior,while the coda waves are complicated.This experiment recognizes the special features of high-speed train records,and demonstrates the potential applications using high-speed railway seismic records.