Kohala (mountain)

About

Kohala (Hawaiian pronunciation: [koˈhɐlə]) is the oldest of five volcanoes that make up the island of Hawaii. Kohala is an estimated one million years old—so old that it experienced, and recorded, the reversal of Earth's magnetic field 780,000 years ago. It is believed to have breached sea level more than 500,000 years ago and to have last erupted 120,000 years ago. Kohala is 606 km2 (234 sq mi) in area and 14,000 km3 (3, 400 cu mi) in volume, and thus constitutes just under 6% of the island of Hawaii. Kohala is an extinct shield volcano cut by multiple deep gorges, which are the product of thousands of years of erosion. Unlike the typical symmetry of other Hawaiian volcanoes, Kohala is shaped like a foot. Toward the end of its shield-building stage 250,000 to 300,000 years ago, a volcanic landslide destroyed the northeast flank of the volcano, reducing its height by over 1,000 m (3, 300 ft) and traveling 130 km (81 mi) across the sea floor. This huge landslide may be partially responsible for the volcano's foot-like shape. Marine fossils have been found on the flank of the volcano, far too high to have been deposited by standard ocean waves. Analysis indicated that the fossils had been deposited by a massive tsunami approximately 120,000 years ago. Because it is so far from the nearest major landmass, the ecosystem of Kohala has experienced geographic isolation, resulting in a u

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