On the relationship between seismic amplitude and charge of explosive fired in routine blasting operations

An account is given of an investigation into the relationship between charge of explosive fired and seismic amplitude in routine quarry blasting. By keeping the instrument fixed over the investigation and by choosing a suitable recording position the effects of site factor can be considered to have been reduced to a practical minimum. The observations, which were made at distances of approximately 400 feet, give a relation between first peak amplitude and charge of the type, C=Q⋅A1.242 where the factor Q varied between 1 and 3 approximately and would apparently be assignable to varying blasting conditions. The results have also been reviewed in the light of an amplitude square relation modified on the supposition that the energy loss involved in practical blasting is a function of the charge.