These are electromagnetic in nature. One of the primary uses of ELFs is to communicate with our submarines. Dr. Andrija Puharich, a highly respected researcher, in an attempt to warn U.S. officials about Russian use of ELFs, set up an experiment. They were sealed in a metal room that could not be penetrated by a normal signal. Puharich then beamed ELF waves at the volunteers.
ELFs go right through the Earth and, of course, right through metal walls.
Those inside couldn't know if the signal was or was not being sent. John DiNardo Reposted from an original post by Thant Tessman.