![]() The Big Island was built by five different volcanoes. Lo’ihi, an island-in-progress growing off the southern shore of the Big Island, is currently underwater and should emerge in about ten thousand years. The island of Hawaii is the youngest in the Hawaiian chain-at least, of those above the waves. The oldest islands in the long archipelago (at least, the ones that are still above the water’s surface), about 3,000 miles to the northwest, were born about 60 million years ago. The older islands of Hawaii-like Kauai and Ni’ihau-used to sit where Kilauea is today about five million years ago. At that point, the volcanoes on those islands go extinct. As it drifts, it drags the islands far enough away that they’re cut off from the magma source below. The hot spot seems to be fixed in place, percolating like a constantly boiling kettle that provides a steady supply of magma coursing upward toward Earth’s surface.īut the tectonic plate that sits on top of the mantle drifts slowly on geologic timescales-currently, it’s moving a few inches northwest every year. The magma comes from a “ hot spot” deep in Earth’s mantle. ![]() The new mound of hot rock kept growing a few inches taller each year until, after 50,000 or 100,000 years, it breached the surface of the Pacific Ocean. A fountain of hot melted rock-magma-from deep in the mantle, streamed upward until lava bubbled up into the sea. The first glimmer of the very first Hawaiian island poked up out of the ocean floor over 60 million years ago.
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