Apparently the maximum &#x27;plausible&#x27; (which is a generous modifier) earthquake on the San Andreas is about an 8.3, but the entire fault line from Mexico to Northern California would have to rupture simultaneously. You&#x27;re right that we&#x27;re unlikely to see an 8.5.<p><a href="http:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;science-nature&#x2F;what-will-really-happen-california-when-san-andreas-unleashes-big-one-180955432&#x2F;?no-ist" rel="nofollow">http:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;science-nature&#x2F;what-will-reall...</a>