Figure 6. Real-world ground vibration data for a brownfield infill site between
two existing buildings. With the adjacent factories running, ground
vibration levels were high enough to preclude high-end microelectronics
manufacturing at the infill site. During a planned factory shutdown, site
ground vibration levels fell to acceptable levels, illustrating the impact of
poorly isolated machinery. Note the large tones, each corresponding to a
specific shaft speed, in the factory-running condition.