Geology

Geology of Hawaii


Hawaii’s volcanoes


Everybody knows Hawaii has volcanoes. In fact, the Hawaiian islands are completely built up from the ocean floor. A volcano-making machine seethes deep beneath the island of Hawaii that geologists call a hot spot. Over the past 44 million years it has churned out 82 volcanoes that today form a vast archipelago that stretches across the Pacific. As if on a colossal assembly line the islands were built in succession over the hot spot then borne away to the northwest by movement of the Pacific tectonic plate. Hot spot lava oozes slowly and builds huge, rounded mountains by slow accretion. Hawaii, the youngest island, is still under construction. Two of the world’s most active volcanoes, Mauna Loa and Kilauea, continue to pave over existing island real estate and create additional acreage. Lo’ihi, a new seamount 20 miles (32km) offshore about 3,000 ft. (915m) below sea level, and fired by the same hot-spot, is giving birth to the chain’s next island due to rise above the waves in another 60,000 years.

content-img