INJURY TEST. “A breach in the mound also alters the shape of the mound’s AC perturbation field. Whereas the undisturbed mound has a field that is distributed roughly uniformly with respect to the mound surface, the field in a damaged mound now has a focus at the site of injury, where wind-induced transient perturbations will be most intense. Once an unexpected AC perturbation has drawn a termite swarm from the nest into the mound, the distorted AC field must be interpreted so that repair efforts are ultimately focused at the site of injury.”
https://link.springer.com/article/10.1007/s12304-016-9256-5