No: The L.A. array is not ready for prime time

Although much interest will focus upon the temporal behavior of observed deformation, the principal justification for the SCIGN array is that within a 5‐year interval it will provide an accurate and detailed determination of the velocity field in the Los Angeles basin that can be used to identify the active faults and estimate their secular slip rates. Obviously, the accuracy of the measurements will determine the success of the SCIGN array in reaching its objective. Over the past several years, Duncan Agnew, Hadley Johnson, and Frank Wyatt have developed arguments that quantify the accuracy likely to be obtained in the measurements and the accuracy that will be required to resolve slip rates on individual faults. In view of those arguments I do not believe that the SCIGN strategy can accomplish its objective. Instead, a mix of annual and continuous GPS surveys may be a more cost‐effective way to accomplish what actually can be achieved.