Amniphon was a Federation colony world located near the Federation-Cardassian Union border in the Alpha Quadrant Demilitarized Zone. In early 2371, a massive rockslide suspected to have been triggered by Cardassian agents caused casualties in the thousands, as well as the destruction of much of the planet's computerized record system.
When Starfleet Lieutenant Tuvok began his undercover infiltration into Maquis, his records were altered to indicate he and his family had moved to Amniphon in 2368, and that his mate and their children were killed in this tragedy. (VOY - The Brave and the Bold, Book Two novella: The Third Artifact)