Using the cube-root scaling law for explosive sources, I estimate the source time functions and yields of explosions directly from seismograms for two explosions in the same location. The path effect between source and receiver is eliminated by finding a ratio filter that shapes the seismogram of the smaller event to the seismogram of the larger. If the noise is small, the convolution of the filter with the source time function of the smaller event yields the source time function of the larger event. The two source time functions are also related by the well-known scaling law in which the injected volume is proportional to the yield and the time constant is proportional to the cube-root of the yield. These two independent equations are solved for the two source time functions, and the seismograms are then deconvolved to recover two estimates of the earth impulse response. The method is applied to seismograms from the North Korean (NK) underground nuclear tests, using measurements of Nevada Test Site tests for calibration, giving estimates of the source time functions and yields for all five events. The method can readily be applied to land seismic exploration with dynamite, for which the data processing is easier, because the locations, origin times and yields of the explosions are known.
Presentation Date: Tuesday, September 26, 2017
Start Time: 3:30 PM
Presentation Type: ORAL