A Seismic Experiment Using Quarry Blasts Near Sydney

Abstract

The seismic waves generated by quarry blasts from 2 to 6 tons in weight, over an interval of 7 months, at Prospect, about 30 kIn west of Sydney, are examined. Shot times at the quarry were measured from radio time signals. The waves were recorded by seismographs at 10 seismological stations ranging in distance from 20 kIn (Riverview) to 380 kIn (Geehi in the Snowy Mountains). Analysis of the seismograms indicated two main bodily-wave phases, called PI and S1" The SI waves, which possess considerable energy relative to the compressional first-arrivals PI' appear to be shear waves generated in part by the unsymmetrical nature of the source.