Earth-probing tomography

Global tomographic surveillance - Ionospheric heaters as RADAR imaging systems

Earth-probing or Earth-penetrating tomography surveillance

Detection of underground weapon facilities

This reference from Popular Science magazine says how Earth-penetrating tomography can be conducted using ionospheric heaters located in high latitudes. This allows among other subsurface monitoring "depending on the geological makeup and subsurface water conditions in a targeted area" and possibly the detection of "underground weapon facilities".

Excerpts:

"Earth-penetrating tomography is a startling potential use of ionospheric heating. The method would work by beaming radio energy into the Auroral electroject."

"The radio energy then disperses over large areas through ductlike regions of the ionosphere, forming a virtual antenna that can be thousands of miles of length".

Note that this would be a virtual antenna generating ELF waves through complex interactions of the radio waves with the ionosphere.

"Such an ELF antenna can emit waves penetrating as deeply as several kilometers into the ground, depending on the geological makeup and subsurface water conditions in a targeted area."

"Aircraft or satellites stationed overhead would then collect the reflected ELF waves and relay them to computers at a processing station, where subsurface inhomogeneities that trace the outlines of structures such as underground weapon facilities can be detected. North Korea and Iraq, where buried nuclear weapons labs are believed to exist, would be prime candidates for earth-penetrating tomography surveillance."

Subterranean mapping - subsurface detection

As mentioned at the page of the Stanford ELF/VLF group, "ELF/VLF waves may in fact be the most reliable means of subterranean mapping, or detecting underground structures". More information is provided at the "Subsurface detection" page.

HAARP conducting Global Ground tomography for imaging of underground structures

https://youtu.be/7peh2Z6E3A0?si=awj4e36XWJadvpFO&t=4768