Kaua`i is the northernmost of the major islands in the Hawai`ian chain. As with the other islands, Kaua`i is really the top of a very tall volcanic mountain, rising from the seabed more than three miles below.
Geologists tell us that these islands were created as a huge subsea plate of the earth's crust slowly passed over a hot spot in the earth's mantle. As the plate gradually moved toward the northwest, each of the islands in the chain was formed in succession by volcanic activity over the hot spot. Of the major islands, Kaua`i is therefore the oldest. The "Big Island" of Hawai`i, being furthest to the southeast, is currently over the hotspot and is still in the process of being formed, although geologists haven't completely written off the possibility of lingering volcanic activity on neighboring Maui as well.
Current theories not withstanding, Hawai`ians know the islands were actually created by Mistress Pele, the Goddess of Fire. And even in ancient times, they didn't need a geologist to tell them that Pele made Kaua`i first.