From Leon's observation, the Abyssal Scar was truly dangerous, but it was not like he didn't know about that before his personal observations.
Before his observation, he already did his research.
Since waking up from his coma, apart from focusing on his construction projects, his side project had been gathering and compiling more information about the Abyssal Scar that what he already knew.
Leon did his homework.
A long time ago, he learned that Neo-Tokara was not as big as he expected. This is Earth, but the Endless Ocean already devoured more than 90% of the total landmass of the planet, devouring all 7 continents and leaving just one combined continent remaining.
That combined continent is what is called Neo-Tokara today, and it spans just 2 million square kilometers across.
Leon learned this through the map that he created long ago.
