[Retric]

The problem is if the entire west coast adds up to 1 million people at the beach it might make very little difference which state their in. A 7pm July 4th quake resulting in a massive Tsunami would be vastly more deadly than an identical 4am quake the next day.

[lambdasquirrel]

If there were ever 1 million people heading to the PNW coast collectively, even on 4 July, the PNW would know it. Routes like the 26 out of Portland or the redwood highway in Oregon / California cannot handle that much traffic. The road to Gerlach, NV gets jammed up by Burning Man traffic, so that should give a good estimate of how many people there can possibly be out there.

Also, unlike in California or the East Coast, these are not quick jaunts to the ocean.

[Retric]

You misunderstood, natural disasters don’t care about state lines or even national borders.

It’s likely no one state adds up to 1 million people, but collectively people at in or near pacific ocean in the US, Canada, and Mexico are at risk. So, if you want to understand the risk from such an earthquake you add everyone together.