Recent technological innovations in magnetometer design has produced a generation of machines capable of rapid survey at fine sensitivity levels. A small scale resistivity survey was initiated in May of 1992 in an attempt to trace the line of the inner stockade wall. The north-south transects were spaced about three meters apart and the southwestern corner of this survey area was located at N15,E120. The remaining two transects were each fifteen meter long and three meters apart with the southwest corner at N17,E145. The magnetic survey was largely unsuccessful in detecting the stockade trench due to the relatively shallow nature of the trench and the low quantities of magnetically susceptible materials in the trench.
Resistivity surveys measure the ability of a volume of soil to conduct an electrical current.
The primary factor in a soil's ability to conduct electricity is its ability to retain water, a property which is heavily influenced by the amount of organic matter it incorporates. Both the pit features and the trench were composed of a more highly organic soil than the surrounding soil matrix. Due to a miscalculation as to the probable path of the stockade walls many of the resistivity transects completely missed the stockade trench. References Cited Weymouth, John W.1986 Geophysical Methods of Archaeological site Surveying. In Advances in Archaeological Method and Theory 9.