Canie, there is a kind of mutant sea floor spreading under southern Salton Sea; no active subduction. There has been some talk over the decades that the subduction zone off of south-Central California, that stopped subducting probably at 19 million years, is being overridden by thrust faults, so could be a little like subduction, but very little. I've worked on some of the thrust faults way out near the top of the escarpment above the paleo-trench. There have been thrust earthquakes way out there in the mid 20th century...I think 5s or 6s.

Chris