Method for extracting Rayleigh surface wave frequency dispersion curve

Abstract

The invention discloses a method for extracting a Rayleigh surface wave frequency dispersion curve. The method comprises the following steps: a, performing Fourier transform on noise cross-correlation signals recorded by a seismometer pair which are spaced by R to obtain a frequency spectrum W(f); b, performing Gauss narrow-band filtering on the obtained frequency spectrum to obtain WG(f); c, extracting a real part curve of the WG(f), finding out null points of the real part curve, and recording fn as the frequency of the nth null point; d, finding out a root of a first-class zero Bessel function as Zn; e, solving a Rayleigh surface wave phase velocity value V(f) being equal to 2pifnR / Zn at a single frequency point according to the relation between a real part curve of a cross-correlation spectrum and the first-class zero Bessel function; f, connecting and drawing the solved phase velocities of single frequency points into a smooth curve as a frequency dispersion curve of Rayleigh surface waves. By using the relation between the Bessel function and the cross-correlation spectrum, the calculation efficiency of the frequency dispersion curve is effectively improved.

Description

technical field [0001] The present invention relates to the key technology of the Rayleigh surface wave detection method in the field of engineering seismic exploration or deep earth structure detection, that is, through the extraction of the Rayleigh surface wave dispersion curve when inverting the underground shear wave velocity structure, I use the seismic record cross-correlation spectrum to realize Based on the relationship between the internal curve and the first kind of zero-order Bessel function, the dispersion curve of Rayleigh surface wave is extracted. Background technique [0002] Rayleigh surface wave is an elastic wave that propagates along the free surface of the earth, and its speed along the surface is related to the elastic parameters of the medium in the depth of the wave, including the density of the medium, the velocity of longitudinal waves and shear waves, and the main influencing parameter is the shear wave of the medium speed. Rayleigh waves have di...

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Problems solved by technology

[0007] The present invention mainly solves the problem that the phase travel period n cannot be accurately determined in the existing method for calculating the dispersion curve, and calculates the phase velocity through the corresponding relationship between the real part of the cross-correlation spectrum and the first zero-order Bessel function, so that it can avoid Open the estimation of the phase travel period n to improve the accuracy of the calculation results

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