Modern Site Discovery Techniques
While most archaeological sites are discovered by on-the-ground study of the landscape, researchers have turned to other methods, such as aerial photography and geophysical techniques, to find and learn about sites.
The Earthwalker site was visible to European-Americans who moved to Clark County in the late 1700s, but by the 1900s, it was difficult to see. It was only through examining aerial photographs - that showed differences in vegetation growth - and magnetic gradiometry that archaeologists rediscovered the site.
Magnetic gradiometry measures differences in Earth’s naturally-occuring magnetic field. Magnetometers map these differences to identify the magnetic signature and location of certain human-altered deposits, like refilled ditches, hearths, storage pits, houses, and other remnants of human-made features.