- last post: 01.01.0001 12:00 AM PDT
Basis is a moon that orbits the planet Threshold. Alpha Halo (Installation 04) was next to Threshold and Basis. When the Chief destroyed Alpha Halo, some of the wreckage landed on the Basis moon.
As for Beaver Creek and Coagulation, I'll assume that they are structures on Delta Halo (Installation 05) that are very similar to the Battle Creek and Blood Gulch structures of Alpha Halo.
As for Waterworks, I'll assume it's just some cavern on Delta Halo.