The Characteristics Analysis And Application Method Study On Seismic Backgrond Noises

The paper aimed at seismic background noise that is present abroad in the seismology research area. To recognize the characteristics and application value of the noise, the theory analysis, the numerical simulation, the modeling analysis and fields observation methods are employed basing on the signal processing, railway vehicle engineering, and the dispersion field theory. The study and analysis give out conclusion that the seismic background noise can be used as a valuable signal in exploration and the explanation can be found in known and random seismic background noise study. The fruits of this paper comprising some parts as following:The source characteristic of random seismic background noise was researched through analyzing consulting the dispersion field theory and the time reversing invariability theory. The new theory we used can recognize the useful signal ensconced in lower S/N signals, although some characteristics of the source, such as the position, the radiation direction and the power value of the source, are not known in advance.Based on the Lamb's theory in 1904, the source mechanism of the running source are analysis and the random vibration theory model and founded. The study indicates that the ground-borne noise mechanism can be explained by point or linear load running in Elastic Half Space.The kinematics and dynamics characteristic of seismic waves induced by 2 kinds of special sources were analyzed quantitatively through the numerical simulation and modeling analysis. The characteristic of random seismic background noise was analyzed using the continuous signal got from the fixed seismic stations. The region sensitive and direction sensitive of the former are greater than the later in different frequency segments. The determined seismic background noises are partitioned into 2 categories, higher S/N signals by running sources and very lower S/N signals by traditional sources. After the spectrum analysis and modeling contrast analysis, the imaging processing is done to the former one using Source Scanning Algorithm. Different parameters, including amplitude, frequency, transmitting speed and transmitting distance, can be got from the inter-correlation of the recorded signals. The study indicates that random noise can be effected by the anisotropy of stratum and its radiation is not symmetrical. The signals induced by running trains have high power and high S/N value. The Rayleigh wave got by BTW24 has steady frequency scope and main frequency, and its energy is weaken with distance between the source and receiver.