Determining resonant frequencies and magnetic influence factors of materials in the earth

An apparatus comprising:

• a magnetometer configured to determine a current magnetic field strength at a test location above a quantity of material buried at the test location, wherein the current magnetic field strength at the test location is a current strength of the earth's magnetic field at the test location;
• a direct current (“DC”) source;
• an antenna comprising a rod and a coil wrapped around the rod, wherein a DC current from the DC source transmitted through the coil induces a coil magnetic field in the antenna, wherein a magnitude of the coil magnetic field strength is within a range comprising the determined current magnetic field strength of the test location;
• a transmission circuit configured to transmit a test signal from the antenna, wherein the antenna is positioned at or above a ground level at the test location, the test signal comprising a test fundamental frequency;
• a wave detector configured to detect, at the test location, a reflected wave comprising the test fundamental frequency on the antenna;
• and
• a depth calculator configured to vary the test fundamental frequency while the transmission circuit retransmits the test signal and the wave detector detects a reflected wave until reflected waves of various test frequencies are detected and a resonant frequency calculator is configured to identify from the detected reflected waves a resonant frequency corresponding to a maximum magnitude of the detected reflected waves, wherein the material comprises molecules with a resonant atom and at least one atom different than the resonant atom, the resonant frequency derived from the current magnetic field strength.