Santorini / Thera
SpeculativeProposed by Spyridon Marinatos; Galanopoulos & Bacon
The Late Bronze Age Minoan eruption was a real VEI-7 catastrophe that devastated a sea-trading culture — the closest thing to a historical kernel. But it is in the Aegean (not beyond Gibraltar), ~1600 BCE (not 9600), and far too small. Proponents must "divide Plato’s numbers by 10" to make it fit.
The caldera is real and the catastrophe was real — this is a flooded volcanic crater 12 km across, left by a VEI-7 eruption. What it is not is Atlantic, 9600 BCE, or continent-sized.