Multiple Seismic Events
Semiannual technical rept. no. 5
WISCONSIN UNIV-MILWAUKEE DEPT OF GEOLOGICAL SCIENCES
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This report, dealing with an investigation of multiple seismic events and first zone discriminants, provides results obtained from an investigation of the detection capability of various seismic networks. Such studies are necessary to quantitatively define the detection potential of a given network or to define the network necessary to achieve a required detection potential. The detection surface was determined at individual points by determining the minimum magnitude event necessary to yield an 80 percent probability of detection by at least 3 stations of the assumed network. By iterating the minimum magnitude calculation over a series of grid points spaced at an interval of 0.25 deg within the area of interest, a detection surface appropriate to that area and for the assumed station coverage was obtained. Since the program for calculating the detection surface uses station distribution, number and noise level, it was possible to investigate the effects, on the detection surface, of a change in one of these parameters while the others were held constant. The effect of station noise was also investigated by using several noise levels at a station 500 km from the grid center. The calculations were applied to the NTS area to demonstrate changes in the detection thresholds occurring in five year intervals since 1933. The results demonstrate the need for quantitative consideration of station placement to ensure maximum detection capability.
- Seismic Detection and Detectors