Integrating GPR and RIP Methods for Water Surface Detection of Geological Structures

Abstract

Geophysical surveying in water-covered and swampy areas is particularly challenging. This paper presents a new survey strategy for such surveying that integrates ground penetrating radar (GPR) and resistivity image profiling (RIP) methods at the water surface to investigate geologic structures beneath rivers, ponds, and swamps.Two test sites, a pond and a lake, have been selected to evaluate this new survey strategy. Experiments in both areas have been successful in delineating the structure of underlying gravel layers. The depth of water and shallow structures obtained from GPR data provided an effective constrain during processing of RIP data. Deeper structures were delineated using RIP data. The integration of GPR and RIP methods conducted at the water surface was successfully applied to map the Hsincheng fault crosscutting the Tourchyan River in Hsinchu County.This paper shows that the use of GPR and RIP at the water surface is efficient in mapping geological structures beneath water. The proposed approach suggests the potential for conducting geophysical surveys along rivers and drainage canals in urban areas, places where roads and buildings impede other methods designed to detect active fault.

Sinkhole risk assessment by ERT: The case study of Sirino Lake (Basilicata, Italy)

“…Less common are electrical resistivity measurements in wetlands, ponds, and lakes. Examples of applications have been reported by Baumgartner (1996) who used electrodes located underwater and orientated vertically, Mansoor and Slater (2007) who performed aquatic electrical resistivity imaging to predict spatial and temporal patterns of pore-fluid conductivity in wetland soils using fixed floating electrodes, and Yang et al (2006) who integrated GPR and resistivity image profiling…”

A combined acoustic and electromagnetic wave-based techniques for bathymetry and subbottom profiling in shallow waters

“…Recent studies have adopted the use of combined geophysical tools, mainly in geological applications: evaluating near-surface stratigraphy, monitoring sediment fills in the subsurface, estimating water content and water conductivity, and locating the position of the water table and bedrock (Garambois et al, 2002;Schwamborn et al, 2002;Gabriel et al, 2003;Sass 2006;Yang et al, 2006;Sloan et al, 2007). Other successful applications include the use of geophysical techniques to estimate beach thicknesses and volumes (Gunn et al, 2006) and to monitor landslide areas (Bruno and Martillier, 2000).…”

“…The amplitude and the attenuation of the eddy currents created in sediment layers are an indication of the electrical conductivity of the different layers (Telford et al, 1990). GPR surveys image dielectric properties of water and subbottom sediments by carrying or towing the receiver and transmitter antennae in or behind a boat (Annan and Davis, 1977;Mellett, 1995;Yang et al, 2006).…”

Landslide‐dammed lake sediment volume calculation using waterborne ERT and SONAR profiling

“…This allowed us to measure high‐resolution, sufficiently deep, cross‐sections. Similar to Yang et al (2006), who used plastic bottles linked to each electrode to prevent the cable from sinking, in this study the electrodes with attached ERT cables were mounted on polyurethane flotation pads (30 cm × 30 cm × 5 cm). These were linked together with a strong cord and the electrodes could be locked to a stable position by tightening of the cord and fixing it on both banks (Figure 4).…”