Electrode, profile and sand
ERT profile (Geoelectrical Resistance Tomography) Steel electrode in beach sand

Links
- https://www.ifgeo.uni-bonn.de/en/sections/geophysics/news/geophysikalische-messungen-auf-der-nordseeinsel-spiekeroog/spieker.jpg/image_view_fullscreen
- https://www.ifgeo.uni-bonn.de/en/sections/geophysics/news/geophysikalische-messungen-auf-der-nordseeinsel-spiekeroog/spieker.jpg/@@download/image/Spieker.jpg