Spatial scale analysis in geophysics - Integrating surface and borehole geophysics in groundwater studies

Frederick L. Paillet

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Spatial scale analysis in geophysics - Integrating surface and borehole geophysics in groundwater studies

Frederick L. Paillet

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Abstract

Integration of geophysical data obtained at various scales can bridge the gap between localized data from boreholes and site-wide data from regional survey profiles. Specific approaches to such analysis include: 1) comparing geophysical measurements in boreholes with the same measurement made from the surface; 2) regressing geophysical data obtained in boreholes with water-sample data from screened intervals; 3) using multiple, physically independent measurements in boreholes to develop multivariate response models for surface geophysical surveys; 4) defining subsurface cell geometry for most effective survey inversion methods; and 5) making geophysical measurements in boreholes to serve as independent verification of geophysical interpretations. Integrated analysis of surface electromagnetic surveys and borehole geophysical logs at a study site in south Florida indicates that salinity of water in the surficial aquifers is controlled by a simple wedge of seawater intrusion along the coast and by a complex pattern of upward brine seepage from deeper aquifers throughout the study area. This interpretation was verified by drilling three additional test boreholes in carefully selected locations.

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Frederick L. Paillet. 2002. Spatial scale analysis in geophysics - Integrating surface and borehole geophysics in groundwater studies. https://pubs.usgs.gov/publication/70023989

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