USGS

Application of Seismic-Refraction Techniques to Hydrologic Studies

U.S. Geological Survey, Techniques of Water-Resources Investigations Book 2, Chapter D2

by F. P. Haeni


Table of Contents

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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