- "What the hell, man. Those holes could pop up anywhere?"
"You'd think we would have figured out some kind of goddamn defense by now."
"Yeah. Command's tried everything, but nothing works. If the Locust want to come up, they come up."" - —Pvt. Anthony Carmine, Cpl. Dominic Santiago, and Pvt. Marcus Fenix discussing emergence holes.
Emergence holes, otherwise known as E-holes, were ground-level openings into subterranean tunnels dug by the Locust Horde to allow military units to breach and invade the planet's surface. The Locust were capable of digging into most substrata, including natural and artificial stone formations. While Drones were capable of digging smaller E-Holes, Hollow animals enslaved by the Locust, such as Corpsers and Seeders, were capable of producing massive E-holes to deliver hundreds or even thousands of troops.
The only area on Sera generally immune to these tunnels was the Jacinto Plateau, because of its solid granite bedrock.[1] Natural fissures and utility tunnels provided occasional access to emerge within cities located on the plateau, but Jacinto remained the only city unable for the Locust to emerge in. However, the granite base was weakened due to the Locust utilizing the Riftworm to sink cities on the plateau, allowing Jacinto to be vulnerable, as well. Other areas the Locust were unable to dig through were islands in the Serano Ocean because to the Abyssal Trench.
Vibrations and tremors usually precede the opening of an E-Hole. The tremors of an E-Hole could be so great it that could incapacitate those near it. The tunnels leading into surface are usually so tall that falling into one is often times fatal. Emergence Holes would spawn a set amount of Locust before collapsing naturally. E-Holes could be collapsed prematurely by explosives, usually by grenades or the Hammer of Dawn.