Remote Sensing at Fort Lewis College, Department of Anthropology

Near-surface Remote Sensing in archaeology uses geophysical techniques to identify subsurface prehistoric and historic features in place of or prior to excavation. Remote sensing techniques save time and money because they have the potential to identify areas of archaeological significance before investing in labor-intensive excavations. They are also used to identify features that may have been overlooked by standard survey techniques.

The images created through remote sensing techniques are often used to assess occupational patterns and site integrity. Sampling can be done within single sites and over several sites. Comparing the data for numerous sites can reveal site types through the organization and intensity of the anomalies. Intra-site sampling complements survey data by establishing integrity of a site before excavation. Comparing data within a single site has the potential to identify features that may or may not have the same geophysical signatures. Inter-site sampling data along with excavation information helps archaeologists understand a single feature’s context within the greater site assemblage.

Fort Lewis College, Department of Anthropology currently owns and operates three remote sensing instruments; a an FM 36 fluxgate gradiometer, a RM15 resistance meter with a multiplexer, and a White’s LXT  spectrum E series metal detector.

The fluxgate gradiometer and the RM15 resistance meter are Geoscan products and are compatible with Geoplot analysis and interpretation software. The data from Geoplot can be easily imported to Surfer software for production of a variety of final maps (contour, shade plot, relief, etc). 

The FM36 fluxgate gradiometer has a built-in data logger, with memory capacity of 16,000 reading.  It is accurate, light weight, and can be operated by one person. Two sensors, independent of each other, are used to adjust the East-West and North-South alignments. Data are stored in a non-volatile memory and can be output via an internal interface to a portable computer or to a CPU. The memory may be portioned into grids (10 x 10 m, 20 x 20 m, 30 x 30 m) with readings interval at 1 m, 0.5 m, or .25 m. 

The RM15 Resistance Meter, another Geoscan product, is also portable and light weight.  The RM15 resistance meter is mounted on the mobile frame. This allows the instrument to be portable, increasing the number of data points over the more traditional resistivity meter. A MPX 15 multiplexer is designed specifically for use with the PA5 probe array and RM15 resistance meter. The multiplexer provides a much wider range of arrays and applications compared to the use of single adapters. This allows for much faster ground coverage or more detailed area coverage.

The success of the previous work, the monetary and temporal savings, and the necessity of non-intrusive techniques show the importance of remotes sensing to traditional archaeology. The combination of geophysical surveys to the more traditional techniques of pedestrian survey and excavation provide a more productive analysis and interpretation of archaeological field data.

For more information on remote sensing in archaeology go to: http://www.cast.uark.edu/nadag/