We thank Art Frankel for his continuing interest in unraveling the details of the complicated source process of the 1987 Superstition Hills earthquake. His insightful comments and subsequent modeling on our part has helped to resolve some of the differences between the rupture model presented in Wald et al. (1990), hereafter referred to as WEA, and that published by Frankel and Wennerberg (1989), hereafter F&W
