Magnetometers

Magnetometers are instruments for observing the Earth's magnetic field. The following equipment is available in section S1:

Proton Precession Magnetometers
Three Proton Precession Magnetometers from Geometrics Inc. type G-856. These portable instruments detect the Earth’s magnetic total field with a resolution of 0.1 nT. Supplementary equipment (sensor G-866, data logger, external battery) enables these instruments to also run as base-stations.

Portable caesium Magnetometer
(with true simultaneous gradiometer option). Scintrex Smartmag SM-4G. Sensitivity 0.01 nT for all sampling rates. This instrument is mainly used for the detection of small amplitudes anomalies on a local scale.