Thanks Brian. Well, the faults under Los Angeles had been previously inferred after the Whittier quake (Davis et a 1989) and something similar by Shaw and Suppe 1996. The Puente Hills thrust is clearly imaged on industry seismic reflection as published by Shaw and Shearer 1999, and it projects down to the Whittier quake. But that one if just north and east of downtown, and not beneath it (although a M7 would be catastrophic). The deeper faults that may cross beneath Los Angeles basin are, I think, largly inferred. Our manuscript shows seismic reflection images of the offshore parts.

The deep faults are controversial. Many think you can explain the Palos Verdes Hills uplift by oblique slip on the otherwise right-lateral Palos Verdes fault. We document that the Palos Verdes Hills are the tip of the iceberg: the structure is much larger, and it has to grow above a subsiding base level.

Chris