How deep into the earth can radio waves travel?

Question

What depth of metal can radio waves penetrate? Does that depth change with frequency? How about Gamma-Rays and X-Rays?

Answer 1

RF does not penetrate an electrical conductor very far at all because currents short out the electric field quickly. There is a skin depth relating frequency and conductivity to penetrations. It's in the NRL formulary (a surprisingly useful reference).

Ionizing radiation operates outside the conduction band, so penetration has more to do with atomic physics. The general rule is the shorter the wavelength, the deeper it penetrates. And it penetrates less as you increase the atomic number.

Answer 2

Not very far.The shorter the wavelength the easier it is for radio waves to be stopped.

Gama and X-rays are a different matter
The absorption of radiation starts as soon as the radiation enters a material. The process is progressive and continues as the radiation penetrates deeper into the material. Additional energy is absorbed through the various processes of ionization. At some point in the material, there is a level at which the radiation intensity becomes one half that at the surface of the material. This depth is known as the Half Value Layer, (HVL) for that material. Each material has its own specific HVL thickness. Not only is the HVL material dependent, but it is also energy dependent. This means that for a given material, if the radiation energy changes, the point at which the intensity decreases to half its original value will also change.

Answer 3

gamma rays can pass through almost anything, xrays are a little less, but radio waves cannot pass through the full length of the earth but are lucky to get a 1/4 of the way

Answer 4

Somewhere I read that sonar (which is a mechanical wave) can pass though the entire earth, the navy uses it, but I do not know what frequency.