High-resolution 3-D dielectric property models of the shallow subsurface: Integrating direct-push and georadar data
Final Report Abstract
Ground-penetrating radar (GPR) is one of the most popular geophysical techniques to explore the buried subsurface. Especially, in near-surface applications (e.g., archaeological prospecting or problems from hydrology and soil sciences) the GPR technique is increasingly used because it can provide subsurface images with a resolution not achievable by any other geophysical method. However, until today the analysis and interpretation of GPR images is focused on subsurface structures and geometries such as geological layering. The development of approaches towards a more quantitative interpretation (e.g., deriving models of the governing physical properties) is one of the most important topics of current research in the field of GPR because such approaches would open the door for new and advanced fields of applications. In this project, we have developed basic approaches to derive 2-D and 3-D models of target physical properties from GPR data. We realized that such advanced analyses are only applicable in real-world scenarios when calibration data as provided by corresponding borehole or directpush logs are available at selected points across a specific field site. Using such calibration data, we have developed joint-interpretation strategies, which, for example, can be used to derive 3-D hydrostratigraphic models. Such models are prerequisite to understand groundwater flow and transport at a specific site. Furthermore, we have developed an impedance inversion scheme for GPR data, which allows to derive subsurface models of the physical parameters governing GPR wave propagation. Although similar approaches are known from reflection seismology, we realized that the adaption of seismic approaches is not straightforward and, thus, further methodological developments were necessary. In this context, further methodological work was needed, especially, regarding the applicability and evaluation of recent direct-push tools for measuring GPR relevant electrical properties and regarding deconvolution of GPR data, which is a basic processing requirement for successful impedance inversion. The results of this project demonstrate that the analysis of GPR data is not restricted to the conventional pure structural interpretation of the data and that, especially, the combination of GPR with direct-push logging offers new methodological possibilities. Such advances have the potential to further broaden the applicability of GPR towards a detailed quantitative characterization of near-surface environments.
Publications
- 2009. 3-D georadar and its potential in site characterization: from structural images towards petrophysical parameters. NovCare 2009 Conference
Tronicke, J., and Schmelzbach, C., and Boeniger, U.
- 2009. Combining ground-penetrating radar reflection surveying and direct push measurements for high-resolution subsurface imaging: A field example. Proceedings of the 5th International Workshop on Advanced Ground Penetrating Radar IWAGPR2009, 88–92. (5 pages)
Schmelzbach, C., and Tronicke, J., and Dietrich, P.
- 2009. Integration of ground-penetrating radar data and direct-push measurements for high-resolution subsurface characterization. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG)
Schmelzbach, C., and Tronicke, J., and Dietrich, P.
- 2010. Mixed-phase deconvolution of ground-penetrating radar data. Near Surface 2010, A12. (4 pages)
Schmelzbach, C., Scherbaum, F., Tronicke, J., and Dietrich, P.
- (2011). Bayesian frequencydomain blind deconvolution of ground-penetrating radar data. Journal of Applied Geophysics, 398, 615-630
Schmelzbach, C., Scherbaum, F., Tronicke, J., and Dietrich, P.
- (2011). Three-dimensional hydrostratigraphic models from ground-penetrating radar and direct-push data. Journal of Hydrology, 398, 235-245
Schmelzbach, C., Tronicke, J., and Dietrich, P.
