NY-NEX Rayleigh Wave Signal and Noise Analysis at a Seismic Array.

摘要

Conventional frequency wave number processing of array data was used to estimate the azimuths and phase velocities of fundamental mode Rayleigh waves in the geology and ambient noise setting at North Haverhill, New Hampshire. These estimates are compared to true azimuths between known shot to array site locations to determine the horizontal refraction of Rg waves due to the regional geology and the variation of azimuth and phase velocity estimates due to additive noise. The analysis was based on calculations of the spectral density function P(Kx,Ky,f), a measure of power as a function of frequency and wave number for propagating waves. This study measured 0.3 to 1.0 second second period Rg waves with phase velocities ranging from 2.5 to 2.9 km/sec having refraction raypaths with a lateral velocity gradient. Keywords: Seismic data processing; Seismic waves refraction; Regional geology; New York; New England.