Human Perception

Beginning in the 1930s, research was conducted with volunteers to determine sensitivities to vibrations. Although people are sensitive to sounds and vibrations, it is difficult to quantify perceptions. Inside a structure, people will feel the building shake and hear the objects around them rattle such as windows and knick-knacks on walls. When an event is perceived, some people will say that they felt very strong vibrations, even if the vibration was too low to be felt outside. The reactions of people are best understood when observed in their own homes during times of real-life events. These reactions may not be the same as those of volunteers under controlled conditions.

Human response to blasting is subjective, as two people will react differently to the same vibration event depending on where they are in a structure, their frame of mind and their personality.  Unfavorable reactions to vibrations may often result in complaints. When residents feel a blast, they may become concerned about damage to their home.

The threshold peak particle velocity of ground vibration perception is about 0.51 mm/s (0.02 in/s) for most people. This is 1/100 of the limit of 50 mm/s (2 in/s) commonly used for construction blasting or in reference to below the chart bounds.

People in different living environments will perceive blasting as either positive or negative.  If a project is not perceived as beneficial to a community, blasting on the project may be unwelcome. On the other hand, blasting on a project that is highly desired may be favorably viewed. Long-term projects near communities are often viewed unfavorably as opposed to short-term projects. While the physical effects of vibrations do not change over time, the social attitudes may change greatly over time.

During a blast vibration event, people inside a building tend to perceive\experience\feel the vibrations differently than people outside a building. People inside a structure are immersed in the vibration event and often cannot tell the source of the vibration. The windows may rattle and there may be other structure responses that enhance their perception of the event. They can perceive structure vibrations that are well below levels that could possibly cause threshold damage. On the other hand, a person outside a structure will not notice any of the structure responses. Therefore, their perception of the event will generally be much less.