So How Do We Know About Historic Earthquakes?

So I’m convinced that Dr. Know has been reading my posts. And the fact that this week’s question (AGAIN!) focuses on disaster is his super secret way of saying that my love is not unrequited. Check it out:

A colleague gave me this “WWsomething” rag, and I had the misfortune of opening it to your column. So, there was a big coastal earthquake 300 years ago, huh? How do they know? Who was in Oregon in roughly 1711 to know there was “a big one”?—Bill T.