A single station approach for subsurface anomaly detection

An innovative seismic imaging method for shallow subsurface anomaly detection is presented. Different from the traditional seismic imaging methods that require the deployment of an array of either one-component or threecomponent seismometers, this method is established based on the use of a single six-component (6C) seismometer, which records three-component translational and threecomponent rotational motions of seismic waves. Because the rotational fifield (i.e., curl fifield) gives information about the spatial gradient of a seismic wavefifield, so the translational fifield together with the rotational fifield can be used to derive the frequency-dependent velocity (i.e., dispersion) of the formation right beneath a seismic station. This single station velocity inversion approach delivers localized subsurface velocity information, making it suitable for imaging smallscale subsurface anomalies. As Rayleigh wave is generally the dominant signal in surface seismic data, the proposed method is established based on the derivation of Rayleigh wave dispersion from single station 6C data. A subsurface velocity model can be immediately constructed by consolidating the dispersion curves derived from individual receivers. The applicability of this method is validated through both numerical modeling and fifield experiment.