Vibration Basics

Ground vibration and air overpressure are normal by-products of the blasting process. In a blast, the vast majority of the explosive energy is used in rock breakage and movement. However, there will always be some residual energy present. This leftover energy is manifested as ground vibration and air overpressure.

As ground and air waves reach a structure, each will cause it to vibrate or respond. This structure response is dependent on the vibration characteristics (frequency and amplitude) and structure type. The response characteristics are primarily related to structure mass and the stiffness.  A structure may not only respond as a whole, but may also have components (walls and windows) with its own response characteristics. However, structure response is not an indicator that damage will occur. All materials have the ability to resist deformation from dynamic forces. It is only when those forces cause strains that exceed the strength of the material that damage occurs.