Geophysical Technique

Magnetic Susceptibility

When we collect magnetic susceptibility data, we’re measuring the ability of the soil and items in the soil to be magnetized. To do this, we use a transmitter coil to send electromagnetic waves into the ground. Objects in the soil produce a secondary electromagnetic field, which our conductivity meter picks up as we walk across the surface.

Magnetic susceptibility works at archaeological sites that have highly magnetic topsoil, which is caused by natural soil formation. Items with lower magnetic readings, such as disturbed soil or structures, stand out from the topsoil.

See What Meg Sees: Instructions for Interpreting the Data

Using the tool below, click on individual grids for a closer look at the Magnetic Susceptibility data Meg and her team gathered at the Camp Lawton. You can toggle between an arieal view of the landsape, the map of the data only, and then read Meg's interpertation of each of the data points as you learn more about what each grid reveals.  Each grid you click on will become highlighted.

 

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Conclusion

Camp Lawton may have been occupied for only six weeks, but with magnetic susceptibility we were able to map extremely ephemeral contrasts in soil properties over small areas. These could be either:

  • the slight change in soil properties resulting from 6 weeks occupation or
  • slight depressions in the earth caused by the compaction of soil under sleeping prisoners, that were then gradually filled in with secondary deposit soils 

The shebang features need to be ground-truthed before we know for sure.

INTERPRET MORE DATA

Ground-penetrating Radar

Ground-penetrating Radar

GPR maps features such as walls, trenches, pits, and more.

Magnetometry

Magnetometry

Magnetic survey measures the variation of magnetic fields of the earth.

Resistivity

Resistivity

Resistance survey measures the subsurface variation in soil.

MEET THE TEAM

Dr. Meg Watters

Dr. Meg Watters

Remote Sensing & Visualization Specialist

Bryan Haley

Bryan Haley

Archaeological Geophysist

Dr. Duncan McKinnon

Dr. Duncan McKinnon

Geophysics Specialist