Ghosts: Vibratory Conveyors

Symptoms of Problem: In a small Midwestern town, the residents complained that they felt movement of their houses, particularly at night. One of the residents stated that her sister would no longer come and visit her because she thought the house was haunted with ghosts. She felt this way because lampshades would move, pictures would rattle and rocking chairs would rock without anyone being in them. Test Procedure: In an attempt to identify the cause of the above problem, vibration measurements were made at several of the houses in the community, along the sidewalks and at a factory located near the [...]