The Japan-kalifornia linkage theory is pretty much toast. Big earth, complex tectonics in between.
But quakes on one fault line can and do cause quakes on others. In many instances multiple faults release as part of the same event. Other times there are delays, but the connection is clear. The Ridgecrest quake a number of years ago is example of the latter, one set of faults in the first quake upset the locked Garlock fault which then broke a few days later.
Thanks - that makes sense.