Typed out long comment and then lost it. Look at the second figure in your link....the San Andreas comes right through there...see seismicity in NW-SE alignment across eastern Salton Sea. They may call the fault something different at Obsidian Butte....but it is the same motion. As far as I am concerned, there is a large swarm going on right up against the main strand of the San Andreas fault. We proposed 4 times to acquire seismic reflection data from a portable raft in Salton Sea but were rejected and finally gave up. We would know more about that link had we been funded....but NSF can't fund everything, and this proposal was not cheap.
Chris