Subterranean concrete vault constructed to house seismic equipment, which has since been removed. There is evidence of the original surrounding fence on site, using old rail line as posts. The only known remaining 1950s Seismic Vault, located adjacent to Spencer Hill in Alice Springs, represents a tangible part of the original `Top Secret’ United States Air Force Seismic Installation established after World War II to monitor nuclear test activities during the Cold War.