by F. P. Haeni
Abstract
Introduction
Purpose and scope
Surface geophysical techniques in hydrologic studies
References
Seismic-refraction theory and limitations
Theory
Interpretation formulas
Two-layer parallel-boundary formulas
Three-layer parallel-boundary formulas
Two-layer dipping-boundary formulas
Example problem
Multilayer dipping-boundary formulas
Formulas for more complex cases
Field corrections
Summary
Limitations
Thin, intermediate-seismic-velocity refractor
Example problem
Insufficient seismic-velocity contrasts between hydrogeologic units
Low-seismic-velocity units underlying high-seismic-velocity units
Example problem
Other limitations of seismic-refraction techniques
Ambient noise
Horizontal variations in the velocity of sound and the thickness of the weathered zone
Accuracy of seismic-refraction measurements
Annotated references
Applications of seismic-refraction techniques to hydrology
Hydrogeologic settings in which seismic-refraction techniques can be used successfully
Unconsolidated unsaturated glacial or alluvial material overlying glacial or alluvial aquifers
Unconsolidated glacial or alluvial material overlying consolidated bedrock
Thick, unconsolidated alluvial or sedimentary materials overlying consolidated sediments and (or) basement rock in large structural basins
Unconsolidated alluvial material overlying sedimentary prorock, which in turn overlies volcanic or crystalline bedrock
Unconsolidated stratified-drift material overlying significant deposits of dense lodgement glacial till, which in turn overlie crystalline bedrock
Hydrogeologic settings in which seismic-refraction techniques may work, but with difficulty
Unconsolidated glacial sand and gravel overlying a thin till layer, which in turn overlies crystalline bedrock
An aquifer underlain by bedrock having a similar seismic velocity
A study area having a surface layer that varies significantly in thickness or material composition
Quantitative estimation of aquifer hydraulic properties
Ground-water contamination in unconsolidated materials
A multilayered Earth with a shallow, thin layer that has a seismic velocity greater than the layers below it
Miscellaneous hydrogeologic settings
Hydrogeologic settings in which seismic-refraction techniques cannot be used
Basalt flows with interflow zones that are aquifers
Unconsolidated sand and gravel aquifer material underlain by silt and clay
Saturated alluvium underlain by a thin confining shale, which in turn overlies a porous sandstone
Annotated references
Unconsolidated unsaturated glacial or alluvial material overlying glacial or alluvial aquifers
Unconsolidated glacial or alluvial material overlying consolidated bedrock
Thick unconsolidated alluvial or sedimentary material overlying consolidated sediments and (or) basement rock in large structural basins
Unconsolidated alluvial material overlying sedimentary rock, which in turn overlies volcanic or crystalline bedrock
Unconsolidated stratified-drift material overlying significant deposits of dense lodgement glacial till, which in turn overlie crystalline bedrock
Unconsolidated glacial sand and gravel overlying a thin till layer, which in turn overlies crystalline bedrock
An aquifer unit underlain by bedrock having a similar seismic velocity
A study area having a surface layer that varies significantly in thickness or material composition
Quantitative estimation of aquifer hydraulic properties-
Ground-water contamination in unconsolidated materials
A multilayered Earth with a shallow, thin layer that has a seismic velocity greater than the layers below it
Miscellaneous hydrogeologic settings
Unconsolidated sand and gravel aquifer material underlain by silt and clay
Saturated alluvium underlain by a thin confining shale, which in turn overlies a porous sandstone
Planning the investigation
Local geology
Available data
Seismic velocities
Objective of the seismic-refraction survey
Site selection
Summary
References
Equipment
Seismograph
Geophones
Geophone cables
Energy sources
Shot cables
Portable radios
Field vehicles
Levels and transits
Miscellaneous tools
References
Field procedures
Reconnaissance refraction survey of a site
Field interpretation and calculations
Example problem
Quantity or quality of field data
Example problem
Field crew
Field records
References
Interpretation techniques
Seismograph records
Manual interpretation techniques
Computer-assisted interpretation techniques
Formulas
Modeling techniques
References
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