By the way, the Susanville event on November 27, 1976 occurred only about half a day
after a Ms 6.8 earthquake off the Coast of Northern California on Nov. 26. It seems
likely that it was a regionally triggered event from that large earthquake. PDE shows
the No. Cal. event with Mb 5.0 (Ml 3.8).
Today's event doesn't appear to have been "triggered" in the same sense as there
have been no large regional earthquakes lately and it has been some time since the
last Mw 7 anywhere in the world. Other types of triggering may apply, however,
it appears that strain had built up in this area sufficient to produce rupture without
a triggering effect. That may mean that a larger localized earthquake can still be
expected in that region.