Geofront
"Geofront" is the publicly used term to describe a massive subterranean cavity. In Neon Genesis Evangelion, it refers specifically the Geofront underneath Tokyo-3 (site of pre-Second Impact Hakone). Unknown to the public, the Geofront under Tokyo-3 is not a naturally occurring structure, but the Black Moon of the Angel Lilith. The Black Moon is a massive sphere, 13.75 km in diameter, though over time it filled with earth and debris. Production drawings reveal that the dome-shaped cavern which constitutes the Geofront in the present day is 6 km in diameter and 900 meters high in the center at its highest point. The very top of the cavern is either absent or has been removed by construction, resulting in a circular opening that accommodates the "Ceiling City" of Tokyo-3's movable buildings. These poke downwards as they are retracted below the surface, which is itself 1.5 km in diameter. The top of the cavern does not reach almost up to ground level, but is some distance below the surface; between the surface and the top of the cavern are 22 layers of plate armor, to defend the Nerv base below.
The Nerv Headquarters building complex was built in the center of the Geofront, and indeed the entire Nerv HQ complex and support city of Tokyo-3 were built in Hakone so that they could be constructed around the Geofront, containing Lilith. The construction led to further excavation deep underground, and the addition of numerous facilities for human habitation, such as access tunnels, trains, defense system and launching systems for Evangelions, among many other things. Reflecting mirror buildings on the surface channel sunlight through large windows in the surface of the cavern, which in turn is reflected by underground mirror buildings, resulting in real sunlight filtering down into the Geofront along with a day/night cycle.
The inside of the Geofront is filled with vegetation including entire forests of trees, possibly as part of the effort to make the Geofront inhabitable and simulate surface working conditions as closely as possible. It also possesses a large lake, at least 70 meters deep (from End of Evangelion) that has at least one Nerv warship present, although whether or not the lake is natural or artificial is unclear.
The Tokyo-3 Geofront was not the only one of its kind. There had been a second, identical Geofront in Antarctica, created by the White Moon of Adam. This Geofront was referred to in classified United Nations files (seen in Episode 21) as "GF-01", presumably for "Geofront-01". It is unclear if the Tokyo-3 Geofront ever had a number assigned to it.
The exact center of the cavern is actually the deep trench (shaped like an inverted pyramid) which levels of the Nerv HQ building descend into (Nerv HQ contains numerous levels below the "floor level" of the GeoFront cavern, thus forming underground installations below an already subterranean cavern). The above floor level pyramid-shaped Nerv HQ building is located slightly off-center, extending off of the central trench, towards the side of the cavern containing the artificial lake. The side of the cavern opposite the artificial lake was not fully excavated, so instead of the roof of the cavern smoothly curving to the floor, the ground level rises to meet it in a series of elevated hills. As a result, while the diameter of the cavern is 6 km along most cross-sections, the side with the hills is somewhat shortened so that the length of the cavern running from the hells to the lake-side wall is perhaps only 5 km.
Notes
- "Geofront" is a real-life term, an English word which was made in Japan. It means "underground space which the people can use for living, manufacturing, etc." by analogy to "waterfront" [Source needed] Because Japan is small and has overcrowding issues, research into the development of underground living and work space has been studied there.
