Crosshole GPR full-waveform inversion of waveguides acting as preferential flow paths within aquifer systems

• DOI: 10.1190/geo2011-0458.1
• Publication Date: 2012-06-26T02:05:44Z
• Authors: Anja Klotzsche; Jan van der Kruk; Giovanni Meles; Harry Vereecken
• Keywords: Ground-Penetrating Radar; Waveguide

High-contrast layers caused by porosity or clay content changes can have a dominant effect on hydraulic processes within an aquifer. These act as low-velocity waveguides for GPR waves. We used field example from hydrological test site in Switzerland to show that full-waveform inversion of crosshole signals could image subwavelength thickness waveguiding layer. exploited the full information data, whereas ray-based techniques are not able such thin waveguide because they only exploit first-arrival times and first-cycle amplitudes. This layer is increase indicates preferential flow path The trapping causes anomalously high amplitudes elongated wavetrains be observed transmitter receivers straddling depth range. excellent fit phase between measured modeled data confirms its presence. new method enables detailed aquifer characterization accurately predict transport applied wide range geologic, hydrological, engineering investigations.