The Submersion

The Submersion, often referred to as the "Solari Cataclysm," was a world altering event, marked the heavy meteor bombardment of during the semi-millennial Starfall across the Sun Sea. This in turn caused many instances of vulcanism across the northern coast of the Great Sea -- from Wessa to Aishelon -- and massive flooding across half the planet.
Earthquakes and eruptions created a tsunami-force force wave which destroyed much of the ancient Solari Empire, causing great devestation to the Island of Kiersea, the land of Menoris and the whole southern coast of Wessa. It also sent shock waves east to the land of Aishelon where tectonic forces caused a sudden shift of the minor Serendi Sub-Plate, and collapse of a great swath of land that later became submerged under the Sea of Serendi.