Echoes of Ceshunai

Ceshunai was a Naiathel Sorceress that created a massive tsunami to hit the northern coast of what is now the Naiathel Empire, and part of Tensun Trading Company territory. Riding the tsunami into battle was the vanguard of the Aventi invading force. Ceshunai's magic was so powerful, that it echoes still, creating tsunamis to hit the same coast again and again. These tsunamis happen every 4-7 years, and the time gaps between them keep increasing, as their strength keeps decreasing. Despite this, they are still devastatingly powerful. Cities still on the coast have built large seawalls, and carefully planned gutters and waterways to deal with the surge. As this is a problem that has lasted generations now, the affected lands have adapted well, and each purge (as the locals call it) becomes less and less devastating.
The Logicmasters of Meridian have setup various devices to analyze and possibly harness power from the next purge. The Aventi allow these Logicmasters to stay in their empire and record the results in order to remain in their good graces.