A resolution analysis of two geophysical imaging methods for characterizing and monitoring hydrologic conditions in the Vadose zone.

[摘要] This research project analyzed the resolution of two geophysical imaging techniques, electrical resistivity tomography (ERT) and cross-borehole ground penetrating radar (XBGPR), for monitoring subsurface flow and transport processes within the vadose zone. The study was based on petrophysical conversion of moisture contents and solute distributions obtained from unsaturated flow forward modeling. This modeling incorporated boundary conditions from a potable water and a salt tracer infiltration experiment performed at the Sandia-Tech Vadose Zone (STVZ) facility, and high-resolution spatial grids (6.25-cm spacing over a 1700-m domain) and incorporated hydraulic properties measured on samples collected from the STVZ. The analysis process involved petrophysical conversion of moisture content and solute concentration fields to geophysical property fields, forward geophysical modeling using the geophysical property fields to obtain synthetic geophysical data, and finally, inversion of this synthetic data. These geophysical property models were then compared to those derived from the conversion of the hydrologic forward modeling to provide an understanding of the resolution and limitations of the geophysical techniques.

[发布日期] 2007-06-01

[学科分类] 地球科学(综合)

[关键词] RESISTIVITY LOGGING;RADAR;HYDROLOGY;MONITORING;SITE CHARACTERIZATION;SPATIAL RESOLUTION;FLOW MODELS;HYDRAULIC CONDUCTIVITY Tomography.;Geophysical instruments.