The deep earth isn't all that well studied, so while we know a fair amount about plate tectonics, there could be hidden factors influencing that action in ways we can't anticipate from recorded history. Who's to say there aren't 1000 or 10k year cycles of earthquakes? Something novel could happen too, but our records don't let us set probabilities for 10k year natural disasters the way we can with 100 year tropical storms, floods, or earthquakes.
reply> Who's to say there aren't 1000 or 10k year cycles of earthquakes?
replyThe Stratigraphy department of the International Union of Geological Sciences would be the obvious first port of call.
Follow that up with an off book chat with digital archivists for commercial oil and gas exploration geologists.
Or influence by the moon just as it pulls on oceans. Lot of liquid magma down there.
replyOr maybe some once in a rare incident involving coronal mass ejections somehow affecting the core of the planet. Could even be a delayed effect.