Geowarps are similar to warpgate's ability to transport you from planet to planet, but geowarps teleport you to the Caverns. A player may broadcast to these gates just as they can a warpgate. Teleporting directly into the caves from a warpgate is not possible, however. When broadcasting from a warpgate to a geowarp you must first exit the warp bubble, then re-enter it and travel through the central beam to teleport to the linked cavern.
Every planet possesses two Geowarps (except for the Oshur Battle Islands, which only contain one Geowarp located on Nexus, but it is presently always inactive), and two caverns are open at any time, meaning that 11 geowarps will be inactive at any given time (2 caverns x 4 geowarps per cavern - 9 planets x 2 geowarps per planet + 1 geowarp on Nexus = 11 inactive geowarps).
However, the programming intentionally makes it so that all the "Neutral" continents are always linked to a cave by a geowarp, even when the caves rotate. This means that one Home Continent of one empire will not have an active cavern link at any give time.