Kauai History and Volcano Islands

According to the hotspot theory, the volcanoes of the Hawaiian chain that moved along this ‘geological conveyor belt’ should get progressively older and become more eroded the farther northwest they travel beyond the hotspot. And they do. The youngest volcanic rocks are found on the island of Hawaii, and the oldest volcanic rocks are on Kauai. Part of the Big Island still sits over the hot spot and taps the magma source to feed its currently active volcanoes. The other Hawaiian islands moved northwest beyond the hot spot and are no longer volcanically active. This progressive drift of the islands from their point of origin over the hot spot can by confirmed by the ages of the principal lava flows on the various Hawaiian Islands from southeast to northwest: Hawaii 0.5 million years old, Maui 1 million, Molokai 1.5, Oahu 3, and Kauai 5 million years old. The volcanic portion of the Midway and Kure Atolls at the northwest end of the chain are 28 million years old.

Following this line of progression, the next volcano in the Hawaiian chain should form southeast of the Big Island. And it is. Evidence shows that a new volcano exists at Loihi, a seamount located about 20 miles off the south coast of the Big Island. Loihi currently rises 10,100 feet above the ocean floor to within 3,100 feet of the water surface. It is similar in form to Kilauea and Mauna Loa with a relatively flat summit and a caldera about 3 miles across. Underwater eruptions at Loihi will eventually break the ocean’s surface to form the next Hawaiian island.

Kauai shows a dramatic history of eruptions, landslides and erosion. Eons of wind and rain have been creating knife-edged cliffs and steep valleys while pounding surf and currents are carving bays and points. Kauai is geologically the most mature of the main Hawaiian Islands with extensive development of broad, lush erosional valleys and coastal features such as fringing coral reefs and sandy beaches. Spectacular Waimea Canyon, at over 2500 feet deep, is Hawaii’s largest erosional valley. The Na Pali coast, on the northwest coast of Kauai, is simply one of the most spectacular wild places left on earth. All along the coast, huge cliffs covered by tenacious greenery form knife-edge ridges with deep canyons graced by waterfall cascades hundreds of feet high. Nearly fifty percent of Kauai’s 111 miles of coastline are lined with beautiful beaches, derived mainly from wave erosion of reef producing coral and algae.

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