The concept of a large aperture seismic array

Abstract

Abstract Both British work at A.W.R.E. and American work in the A.R.P.A. Vela Uniform Program have demonstrated that arrays of seismometers may be used to enhance the signal/noise ratio of distant seismic events over the single instrument signal/noise ratio. In addition, arrays may have the virtue of suppressing signal-generated noise arising in the crust below the receiver. Other Vela research has demonstrated that buried instruments frequently have a lower noise environment than surface instruments. Borehole emplacement may be particularly effective against wind-generated seismic noise. In an attempt to exploit these possible improvements to the maximum extent we are now constructing a large aperture seismological array of buried seismometers. This instrument will consist of over 500 seismometers distributed in 21 clusters over a 200 km aperture. It will exploit modem array signalprocessing techniques. If it performs as expected it will have major implications for worldwide seismological detection systems. The status of and plans for the experimental array are described along with some of the world-wide system possibilities.