These techniques provide a measure of the strain induced in the rock by the detonation front of the explosive plus the kinetic energy applied by the expanding gasses of the detonating explosive.
Bauer et al (1984) state that the actual VOD can be used to calculate the volume fraction of the explosive involved in the reaction at the detonation front.
As the detonation front passes each target location a voltage 'spike' is generated.
There is a loss of shock energy at the interface between the detonation front and the wall of the charge as the shock pulse is propagated into the surrounding material.
The pressure in the detonation front of a column of explosive is related to the initial shock pulse in the rock mass.