Regional studies with broadband data

An experiment was performed in which broadband waveform data were recorded by a seismic network surrounding a series of 8 chemical explosions in a quarry. The experiment is described and all of the waveform data are presented. A velocity model was obtained from the travel time readings and this was used to estimate moment rate tensors for 5 of the events which were single explosions. The results indicate simple source mechanisms for these single explosions, particularly the deeper events. The efficiency with which chemical energy is converted to seismic waves shows a strong dependence upon the depth of the source and this is caused primarily by a decrease in the corner frequency of the source time function as the source depth decreases. When scaled by the size of the explosion, the results for these small chemical explosions are in reasonable agreement with similar results for much larger nuclear explosions.