TY - JOUR A1 - Dietrich, Peter A1 - Tronicke, Jens T1 - Integrated analysis and interpretation of cross-hole P- and S-wave tomograms : a case study N2 - We present cross-hole P- and S-wave seismic experiments that have been performed along a similar to 100 m long transect for the detailed characterization of a contaminated sedimentary site (Bitterfeld research test site, Germany). We invert the corresponding first break arrival times for the P- and S-wave velocity structure and compare two different strategies to interpret these models in terms of pertinent lithological and geotechnical parameter variations. The first (common) approach is based on directly translating the tomographic velocity models into the parameters of interest (e.g., elastic moduli). The second (zonal) approach first reduces the tomographic parameter information to a limited number of characteristic velocity combinations via k-means cluster analysis. Then, for each zone (cluster) further parameters including uncertainties can be estimated. In the presented case study, Our results indicate that the zonal approach provides an effective means for the integrated interpretation of different co-located data. Y1 - 2009 UR - http://nsg.eage.org/ U6 - https://doi.org/10.3997/1873-0604.2008041 SN - 1569-4445 ER - TY - JOUR A1 - Paasche, Hendrik A1 - Tronicke, Jens A1 - Holliger, Klaus A1 - Green, Alan G. A1 - Maurer, Hansruedi T1 - Integration of diverse physical-property models : subsurface zonation and petrophysical parameter estimation based on fuzzy c-means cluster analyses N2 - Inversions of an individual geophysical data set can be highly nonunique, and it is generally difficult to determine petrophysical parameters from geophysical data. We show that both issues can be addressed by adopting a statistical multiparameter approach that requires the acquisition, processing, and separate inversion of two or more types of geophysical data. To combine information contained in the physical-property models that result from inverting the individual data sets and to estimate the spatial distribution of petrophysical parameters in regions where they are known at only a few locations. we demonstrate the potential of the fuzzy c-means (FCM) clustering technique. After testing this new approach on synthetic data, we apply it to limited crosshole georadar, crosshole seismic, gamma-log, and slug-test data acquired within a shallow alluvial aquifer. The derived multiparameter model effectively outlines the major sedimentary units observed in numerous boreholes and provides plausible estimates for the spatial distributions of gamma-ray emitters and hydraulic conductivity Y1 - 2006 UR - http://geophysics.geoscienceworld.org/ U6 - https://doi.org/10.1190/1.2192927 ER - TY - JOUR A1 - Tronicke, Jens A1 - Villamor, P A1 - Green, Alan G. T1 - Detailed shallow geometry and vertical displacement estimates of the Maleme Fault Zone, New Zealand, using 2D and 3D georadar N2 - In an attempt to map the shallow geometry of the Maleme Fault Zone (North Island, New Zealand) and estimate vertical displacements of selected fault strands, we have collected 2D and 3D georadar data using 100 MHz antennae. The 2D data consisted of three parallel georadar lines recorded perpendicular to the axis of the well-defined graben of the Maleme Fault Zone. These similar to 160 in long lines, which were 7.5 m apart, crossed several fault strands on either side of the graben axis. The processed georadar sections revealed two prominent parallel reflections that originated from the boundaries of Late Pleistocene lacustrine and tephra deposits. Distinct vertical offsets of these reflections allowed us to estimate displacernents at individual fault strands across the entire inner graben. The total displacements represented by these offsets was similar to 10-20% greater than that inferred from geomorphological studies, thus demonstrating the limitations of surface observations for determining cumulative fault movements. The 3D georadar data set, recorded across an area of similar to 70x similar to 20 in to one side of the graben axis, provided key details on individual fault strands. For the 3D visualization of fault-related structures, various spatial attribute analyses based on the cosine of the instantaneous phase proved to be useful Y1 - 2006 ER - TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens A1 - Holliger, Klaus A1 - Becht, Andreas T1 - Multi-offset vertical radar profiling for subsurface reflection imaging JF - Journal of environmental & engineering geophysics : JEEG N2 - The vertical radar profiling (VRP) technique uses surface-to-borehole acquisition geometries comparable to vertical seismic profiling (VSP). Major differences between the two methods do arise due to the fundamentally differing nature of the velocity-depth gradients and transmitter/receiver directivities. Largely for this reason, VRP studies have so far essentially been limited to the reconstruction of velocity-depth profiles by inverting direct arrival times from single-offset VRP surveys. In this study, we investigate the potential to produce high-resolution subsurface reflection images from multi-offset VRP data. Two synthetic data sets are used to evaluate a processing strategy suitably adapted from VSP processing. Despite the fundamental differences between VRP and VSP data, we found that our processing approach is capable of reconstructing subsurface structures of comparable complexity to those routinely imaged by VSP data. Finally, we apply our processing flow to two multi-offset VRP data sets recorded at a well constrained hydrogeophysical test site in SW-Germany. The inferred VRP images are compared with high-quality surface georadar reflection images and lithological logs available at the borehole locations. We find that the VRP images are in good agreement with the surface georadar data and reliably detect the major lithological boundaries. Due to the significantly shorter ray-paths, the depth penetration of the VRP data is, however, considerably higher than that of the surface georadar data. VRP reflection images thus provide an effective means for the depth-calibration and extension of conventional surface georadar data in the vicinity of boreholes. Y1 - 2006 U6 - https://doi.org/10.2113/JEEG11.4.289 SN - 1083-1363 VL - 11 IS - 4 SP - 289 EP - 298 PB - EEGS CY - Denver ER -