Secret of The Hidden Underwater Continent

A phrase that quite accurately characterizes our time, has been floating around the internet for a long time. Born too late to explore the world, born too early to explore the Universe. Indeed, humanity hasn't flown beyond the limits of near-Earth orbit. But In terms of discovering new lands, the anonymous author clearly spoke too soon. As it turns out, in 2017 a new continent was discovered - Zealandia. A couple of years later, scientists discovered that it was directly connected to the most dangerous volcanos on the Earth.
What do this hidden continent and ring of fire have in common?