Finding buried stream channels and other contaminate pathways

This case study illustrates how electrical resistivity profiling was used to map a subsurface gravel deposit and impermeable clay layer.  The geophysical data gave the geologists the information needed to successfully plan new exploratory and extraction wells and aided in designing a cut-off wall.

Geophysics and Alquist-Priolo fault zone investigations

Often young deep alluvium prevents trenches from reaching ruptured soils making determining a fault's location and activity difficult.  Here we illustrate how high resolution seismic refraction was used to find a fault.

Using seismics to find a groundwater source

Finding a buried fault was critical to drilling a water well. Drilling on one side of the fault would create a useful well while drilling on the other would result in a dry hole. This case study illustrates how seismic refraction was used to locate the fault.

Mapping saltwater intrusion along a coastal stream

A small water district wanted to drill a new well in a river bank of a coastal stream. Prior to drilling, the district needed to determine if saltwater had intruded the river bank. This case study illustrates how a combination of resistivity and seismic techniques were used to map the extent of saltwater intrusion along the stream.

Locating underground storage tanks

Prior to purchasing a small shopping mall, a land developer wanted to determine if the tanks of a former service station had been removed. This case study shows how magnetics and radar were used to locate six buried fuel storage tanks.

Liquefaction analysis using both downhole seismics and the multichannel analysis of surface wave techniques

As part of a geophysical study of a groundwater basin for a proposed power plant in the California desert, downhole seismic data and multichannel analysis of surface waves (MASW) data were collected to help determine liquefaction potential. This example shows a comparison of the results from the two techniques.

At J R Associates we stand ready to apply our geophysical expertise to your particular requirements. Please contact us to discuss how our combination of techniques, knowledge and experience can provide you with a window on what's underground. 

 

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J R Associates, 1886 Emory Street, San Jose, CA  95126

Ph: (408) 293-7390 Email: jra@Greatgeophysics.com