In authors previous publications the methods, that were developed at the University of Auckland, NZ, for recording and analyzing microtremors, were described. In this paper, the applications of microtremor measurements to earthquake resistant design of structures are critically examined. Specific applications are discussed and compared with results obtained by the authors. Finally, it is shown that, using computer techniques, it is possible to simulate ground motions which have the characteristics of recorded microtremor motions.