Investigation of structural deformation in unconsolidated sediments using high-resolution sh-wave seismic methods

On-going high resolution SH-wave reflection and refraction surveys are being used to economically detect subtle structural deformation features associated with the active seismicity of the Lake County uplift in the New Madrid seismic zone. The study, to date, has traced faulting into the water-saturated, unconsolidated, late Eocene (and in some instances Quaternary) sediments in the vicinity of the Madrid Bend in the northwestern corner of Tennessee. Using partially reversed expanding-spread refraction/reflection lines and common-depth-point (CDP) reflection surveys, 3+ m of throw has been detected in the late Eocene sediments (Jackson Formation), as well as in what is thought to be Quaternary deposits. It is believed that because of the detail demonstrated, and from the cost effective nature, this technique of investigation will prove to be extremely useful in other studies within the New Madrid seismic zone, as well as throughout the Mississippi Embayment or similar geologic environments.