Supplemental Figure 1 for the Kamerling-Sorlien 1999 AGU abstract. Mapping in onshore Ventura basin is from Hopps et al., 1995, and is on several subsurface horizons. Offshore mapping is by Sorlien and is on Miocene horizons, except south and east of the Northern Channel Islands faults are mapped at the seafloor. Mapping in northern Santa Barbara Channel is by Kamerling and is projected upwards to near the seafloor. Other mapping from Jennings (1994). The area outlined in red has been mapped by us on the top Lower Pico horizon (~1.8 Ma).