Seabed collapse

The seabed collapse north of Deltora led to the combination of Deltora and Pirra, and changed Deltora's landscape significantly. The event had a significant effect in Deltora, causing the island to become fruitful and more liveable, and allowing for trade.

History
The fearsome sea monsters burrowing deep into the seabed weakened the rocky ground of the sea, not knowing what fiery doom lay behind it. One day, the dragons took flight and blocked out the sun. The earth quaked beneath the people’s feet, the sea boiled, and the land changed. In Dorne, the centre of the island swelled and fire burst forth. The people thought that the world was ending, but it merely changed. Once it was over, it revealed that the north shores were now rocky mountains, forced up as the land between the Twin and the Land of Dragons collided and merged, sealed by melted rock.

Eight days after the event, the skies cleared and the people found a wondrous gem in each of their territories, their own talisman. The land blossomed and the people were able to leave their land, for many of the sea monsters died in the clash of fire and water. The people of the Land of Dragons tried to explore the new land, but the mountains separating the lands were full of the deadly creatures that once lived in the sea. Their attempts to sail around the mountains were blocked by powerful magic, and so they forgot about the Twin and guarded their own talismans.

The event was told by a blackbird to Tenna and recorded in the Tenna Birdsong Tales in the stories The Land of Dragons and Fire and Water.

Aftermath
The event had a huge impact on Deltora, specifically its trading. The island became fruitful and no longer did tribes fear the oceans. This allowed for trading between islands.