I love the "ALL TRUE" on the sign. It must be hinting that the park revolves around some sort of Polynesian legend/ghost/god/event, the authenticity of which is up for debate. You'll just have to visit yourself to find out!
This seems like they are holding onto the story they created for the original WonderSea name. It was all about the natives (who have a name I cannot remember) and all the lore of the volcano.