Kohala

Kohala 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, a reversal of 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 km (234 sq mi) in area and 14,000 km (3,400 cu mi) in volume, and thus constitutes just under 6% of the island of Hawaii.