Identification of paleo-liquefaction and deformation features with GPR in the New Madrid seismic zone

GPR surveys were conducted in the New Madrid seismic zone in central US - an area used to be considered unsuitable for GPR applications. The purposes of these surveys are to correlate geological features revealed by trenching and GPR responses and consequently lending a roadway to search for subsurface paleoliquefaction features such as sand dikes and sand blows in a relatively silty and clayey country soil environment. GPR surveys using 400, 100 and 25 MHz antennas were conducted at three sites at Haynes, Arkansas, Dillarhunty, and Sikeston Ridge Missouri. Comparison with shallow shear-wave seismic surveys at the Sikeston Ridge site reveals similar subsurface features in different deformation features at different depths (10 m vs 100 m) along the western scarp of the Ridge. Detailed study to analyze GPR registration of subsurface liquefaction features will be reported at the conference.