Chris Bravo, Department of Defense environmental prototype evaluator, uses a seismic receiver to collect seismic wave data at Fort Eustis, Va., Sept. 10, 2015. The receiver was remotely connected to a sensor that detected seismic and magnetic waves caused by foot traffic, cars and trains. (U.S. Air Force photo by Staff Sgt. Natasha Stannard/Released)

Department of Defense environmental prototype evaluators use a seismic sensor to collect seismic wave data for the DoD at Fort Eustis, Va., Sept. 10, 2015. The data will be used to determine natural phenomenology at military installations. (U.S. Air Force photo by Staff Sgt. Natasha Stannard/Released)

Chris Bravo, Department of Defense environmental prototype evaluator, uses a seismic receiver to collect seismic waves caused by a passing train at Fort Eustis, Va., Sept. 10, 2015. The DoD team coordinated with the 733rd Mission Support Group as well as U.S. Army Rail to gather readings caused by locomotive traffic. (U.S. Air Force photo by Staff Sgt. Natasha Stannard/Released)

Al Dempsey, Department of Defense environmental prototype evaluator, documents seismic sensor readings at Fort Eustis, Va., Sept. 10, 2015. The readings are used as part of an annual data collection of seismic and acoustic frequencies brought on by natural phenomena at military installations. (U.S. Air Force photo by Staff Sgt. Natasha Stannard/Released)

Al Dempsey, Department of Defense environmental prototype evaluator, moves a seismic sensor used to collect seismic wave data at Fort Eustis, Va., Sept. 10, 2015. The sensor was moved closer to shore to pick up a more accurate reading of seismic waves. (U.S. Air Force photo by Staff Sgt. Natasha Stannard/Released)