Range limitation for seismic footstep detection

Abstract

Seismic methods for footstep detection exploit low frequency vibration waves, typically below 100 Hz. There are two limiting factors for detection of human footsteps at these frequencies: walking styles and the background noise floor. The walking style changes the dynamic footstep force on the ground and, therefore, limits the maximum distance at which walkers may be detected. For seismic frequencies, the background vibration noise floor is higher in urban areas than in quiet areas. This article presents and discusses test results of human footstep measurements as a function of distance using the seismic method in quiet and urban areas.