Crimson hues flushed across the early morning skies over the Kingdom of Tonga as Grace Frontin-Rollet spotted a pair of small rocky islands from the bow of the RV Tangaroa. Though the scene was picturesque, a tinge of sulfur in the air reminded the marine geologist what she and a team of scientists had traveled for six days over rough waters to see. In the expansive gap between the two bits of land, hidden on the ocean floor, lay the crater of a massive volcano that erupted just months before in one of the largest and strangest blasts ever seen.

"I don't think the scale of what had happened hit us until we reached the site," says