That looked like an dinosaur extinction event level of meteor and I thought maybe this was some new way of axing a manga.
I'm amazed there was no crater of molten rock, no massive earthquakes as the mantle gets forcefully rearranged, nor dust getting sent up in the atmosphere and blocking all sunlight for years. This isn't some dude making a big splash in a pool, it's an island getting wiped by a giant rock several times its size.
The only consequences were apparently a few big waves and the sea was completely calm after. Even with just that, Cain only appeared to block the waves on the shore near him, so what about in every other direction?