Geophysical techniques that D'Appolonia commonly applies to site environmental studies include:
DC Resistivity – This geophysical method is used to map electrical variations in the subsurface. It is frequently used to map contaminant plumes in ground water, to assess the extent of buried waste and to produce subsurface profiles.
Electromagnetic (EM) methods – EM methods are commonly applied to rapidly map lateral electrical contrasts in the ground (e.g., contaminant plumes in ground water) or to assess the extent of buried waste. EM methods do not provide the degree of vertical resolution obtainable using DC resistivity, but the method allows rapid mapping of lateral variations of subsurface electrical properties withoud placing electrodes in the ground.
Ground Penetrating Radar (GPR) – GPR offers the highest resolution of any geophysical method when soil conditions are favorable. Typical environmental applications that we have conducted with this technique include mapping of buried waste and locating underground storage tanks (USTs), pipelines, and other utilities.
Magnetics – We routinely conduct total field and gradiometer surveys for mapping the distribution of buried metallic waste locating underground tanks. The method can be used to map subtle variations in soil properties that could indicate areas of past excavation.
High Resolution Seismic Reflection – D'Appolonia has conducted research using this technique as a tool for ground water investigations.