Seismic exploration using non-impulsive vibratory sources activated by stationary, Gaussian codes, and processing the results in distortion-free final records particularly useful in urban areas

Claim 1

A method of seismic surveying using non-impulsive vibratory sources that recovers all the essential information of full-waveform recording in a distortion-free manner in an urban area having statutes controlling drive level of such sources to a maximum level F m (t) which, comprises: A. injecting non-impulsive, seismic vibrations into the earth by activating at least one vibratory source with a driving code of Gaussian, zero-mean, stationary characteristics wherein the drive level F m (t) is not exceeded; B. recording the seismic vibrations that have propagated through the earth from said at least one vibratory source to at least one receiver; and C. cross-correlating a full-waveform-preserved representation of said injected vibrations with said received seismic vibrations; the result of said cross-correlation being a seismic survey record that is essentially distortion-free.

Claim 2

A method of seismic surveying using non-impulsive vibratory sources that recovers all the essential information of full-waveform recording in a distortion-free manner in an urban area having statutes controlling drive level of such sources to a maximum level F m (t) which, comprises: A. injecting non-impulsive, seismic vibrations into the earth by activating at least one vibratory source with a driving code of Gaussian, zero-mean, stationary characteristics wherein the drive level F m (t) is not exceeded; B. recording the seismic vibrations that have propagated through the earth from said at least one vibratory source to at least one receiver; and C. cross-correlating a full-waveform-preserved representation of said injected vibrations with said received seismic vibrations; the result of said cross-correlation being a seismic survey record that is essentially distortion-free.

Claim 7

A method of seismic surveying in an urban area having laws controlling drive level of non-impulsive vibratory sources to a maximum level F m (t), comprising: A. generating a Gaussian, zero-mean, and stationary code; B. filtering said code through a filter selected from the class consisting of minimum-phase band-pass and zero-phase band-pass; C. driving at least one substantially linearly-responding seismic vibratory source with the resultant filtered code to inject non-impulsive signals into the earth for a time interval longer than the recording interval of the resultant seismic waves; D. recording the full-wave seismic signals detected by at least one receiver positioned to detect said resultant seismic waves; E. recording a waveform-preserved representation of said Gaussian, zero-mean, stationary code without filtering thereof; and F. cross-correlating said waveform-preserved representation of said code with said full-wave detected seismic signals; the result of said cross-correlating being a seismic record that is essentially distortion-free.

Claim 8

A method of seismic surveying in an urban area having laws controlling drive level of non-impulsive vibratory sources to a maximum level F m (t), comprising: A. generating a Gaussian, zero-mean, and stationary code; B. filtering said code through a filter selected from the class consisting of minimum-phase band-pass and zero-phase band-pass; C. driving at least one substantially linearly-responding seismic vibratory source with the resultant filtered code to inject non-impulsive signals into the earth for a time interval longer than the recording interval of the resultant seismic waves; D. recording the full-wave seismic signals detected by at least one receiver positioned to detect said resultant seismic waves; E. recording a waveform-preserved representation of said Gaussian, zero-mean, stationary code without filtering thereof; and F. cross-correlating said waveform-preserved representation of said code with said full-wave detected seismic signals; the result of said cross-correlating being a seismic record that is essentially distortion-free.

Claim 10

A method of seismic surveying using at least one non-impulsive vibratory source that recovers all essential information of full-waveform recording in an urban area in which the maximum drive level of said source is F m (t), which comprises: A. injecting non-impulsive seismic vibrations into the earth by activating at least one vibratory source with a driving code of preselected Gaussian, zero-mean, stationary characteristics whereby adjacent to said one source, the drive level average with time does not exceed F m but said average is higher than that of a conventional "chirp" signal; B. recording a full-wave representation of said injected vibrations; C. recording a waveform-preserved representation of the seismic vibrations that have propagated through the earth from said at least one vibratory source to at least one receiver; and D. cross-correlating said full-wave representation of said injected Gaussian, zero-mean, stationary vibrations with said full-waveform-preserved representation of said propagated seismic vibrations recorded by said receiver; the result of said cross-correlation being a seismic survey record essentially distortion-free and particularly useful in structural determination in said surveyed urban area.

Claim 11

A method of seismic surveying using at least one non-impulsive vibratory source that recovers all essential information of full-waveform recording in an urban area in which the maximum drive level of said source is F m (t), which comprises: A. injecting non-impulsive seismic vibrations into the earth by activating at least one vibratory source with a driving code of preselected Gaussian, zero-mean, stationary characteristics whereby adjacent to said one source, the drive level average with time does not exceed F m but said average is higher than that of a conventional "chirp" signal; B. recording a full-wave representation of said injected vibrations; C. recording a waveform-preserved representation of the seismic vibrations that have propagated through the earth from said at least one vibratory source to at least one receiver; and D. cross-correlating said full-wave representation of said injected Gaussian, zero-mean, stationary vibrations with said full-waveform-preserved representation of said propagated seismic vibrations recorded by said receiver; the result of said cross-correlation being a seismic survey record essentially distortion-free and particularly useful in structural determination in said surveyed urban area.