Archaeological geophysics

Geophysical surveys are used to create maps of subsurface archaeological
features. Features are the non-portable part of the archaeological record,
whether standing structures or traces of human activities left in the soil.
Geophysical instruments can detect buried features when their electrical or
magnetic properties contrast measurably with their surroundings. In some
cases individual artifacts, especially metal, may be detected as well.
Readings taken in a systematic pattern become a dataset that can be rendered
as image maps. Survey results can be used to guide excavation and to give
archaeologists insight into the patterning of non-excavated parts of the
site. Unlike other archaeological methods, geophysical surveys are not
invasive or destructive. For this reason, they are often used where
preservation (rather than excavation) is the goal.

Geophysics has been applied in the past with intermittent success, good
results are very likely when it is applied appropriately. It is most useful
when it is used in a well-integrated research design where interpretations
can be tested and refined. Interpretation requires a knowledge both of the
archaeological record, and of the way it is expressed geophysically.
Appropriate instrumentation, survey design, and data processing are
essential for success, and must be adapted to the unique geology and
archaeological record of each site. In the field, control of data quality
and spatial accuracy are critical.