Just to be clear, this is not a threat I am concerned with. It makes for an interesting conversation is all. There is a huge difference between the collapse of civilization and an extinction level event. A Yellowstone super volcano could collapse civilizations around the world and collapse populations worldwide, but it would not be an extinction level event. Out of the ashes a new civilization would eventually arise. Small pockets of civilization might make it through reasonably intact. Were I to be amongst the lucky few for whom travel/fleeing was an option, I would head to an equatorial region, perhaps someplace in Northern Australia or failing that to someplace like Costa Rica or Panama. .