Study On The Theory Of Duffing Chaos System And Its Application In Seismic Prospecting

Between deterministic and randomness, chaos is a common nonlinear phenomenon withrich connotation and broad extension. Under certain conditions，chaotic system is sensitive toinitial conditions and has a good anti-noise property，which makes chaos present its uniquefunction in weak signal detection. In this paper based on Duffing oscillator system, thesingle-frequency weak signal and even the multi-frequency weak signal is detected. Moreover,Duffing oscillator can also be applied to the seismic exploration, focusing on the problem ofidentification of weak seismic event based on Duffing oscillator model. The main contentsare as follows:Firstly the basic theory of chaotic system is introduced，and then the principle of weaksignal detection based on Duffing chaotic oscillator is analyzed. The method of detecting theamplitude of the single-frequency and multi-frequency signal is studied. According to thedistribution relationships between the variance peak of output signals and the frequencies ofdriving force, the multi-frequency signal with unknown frequency is detected. Then animproved algorithm is proposed, and its effectiveness and practicality can be tested by a largenumber of simulation experiments. The weak signal detection method based on Duffingchaotic system can be applied to the detection of the weak signal in seismic prospecting. Thechaos system is immune to noise and response quickly to the periodic signal and approximateperiodic signal, which can change the phase state of the chaos oscillator to large-scaleperiodic phase state. Based on this idea, chaotic oscillator is adopted to detect the weakseismic signal in seismic data, and the simulation verifies the validity of the method.Weak signal detection based on chaotic oscillator is a new detection method, which hasremarkable advantages in the detection of periodic signal, the high sensitivity characteristicsof chaos will attract people to make further research. This paper makes a useful explorationfor the popularization and application of the chaotic detection method, which also providesthe basics for the application of nonlinear detection method in seismic prospecting.