I’m halfway through Simon Winchester’s new book, “A Crack In The Edge of The World: America and the Great California Earthquake of 1906”.
Since we live with the SAF (San Andreas Fault) this is good reading: 
Winchester has written an enjoyable synthesis of California history, northern California history–but having much earlier read John McPhee’s “Assembling California”, I find echoes of that great author’s work.
I’m not a geologist and I don’t pretend to understand all of what I’m reading.
Although I’m not done with Winchester’s book, I’ve become aware of one of the main points. Since 1906 most experts believed the quake’s epicenter (the point where the quake started) was in the town of Olema in northern California. That’s because there was so much visible movement of fences and roads there. The Olemans are proud to be at the epicenter–but it turns out the truth is Olema is not the epicenter. Mussel Rock in Daly City is! Well, Mussel Rock is very much within driving distance of El Granada. You can reach it by driving through Pacifica and it’s a beautiful, jagged cliffy beach (forget about the dump that’s nearby) where people hangglide.
Unlike Olema, which is really not the epicenter but the proud pretender, Daly City is the epicenter but Daly City doesn’t want anyone to know.
Experts say Mussel Rock, and not Olema, 
was the epicenter of the 1906 quake but locals don’t want the blame or fame.
If you look at earthquake maps, the land west of the famous San Andreas Fault is on what is called the Pacific Plate–this is the “coast” of California where there sure isn’t a lot of land there compared to what’s on the other side, the east side of the San Andreas Fault which is located on what is called the North American Plate. And the rest of the US is sits on the North American Plate. Are you with me?
In El Granada we are living on the Pacific Plate.
That’s just part of the story. The San Andreas Fault has three parts–briefly, the northern and southern parts are locked in to the North American Plate but there is a 125 mile stretch in the center (at Parkview, California) that is not “locked in” and is always nervously fidgeting, caushing, if you think about it, immense stresses on the northern and southern parts. Pushing and pulling to free itself from the north and south. That’s the way I understand it.
Did I get it right?