Don, the offsets were probably only for the 1857 and 1906 earthquakes. But, these are probably maximum offsets-the offset is not that big everywhere on the fault rupture-I think the 1906 offset in the Santa Cruz Mountains was only a couple meters, so it was ready again by 1989....The maximum offset for 1857 was in Carrizo (sp?) plain, and that may be characteristic of that area.