FOUR MILE WIDE VOLCANO UNDER THE PACIFIC IS THE BIGGEST VOLCANO IN THE WORLD

TAMU MASSIF - HUFFINGTON POST  link to full article

"The entire volcano is bigger than the British Isles or New Mexico.

Despite Tamu's huge size, the ship surveys showed little evidence the volcano's top ever poked above the sea. The world's biggest volcano has been hidden because it sits on thin oceanic crust (or lithosphere), which can't support its weight. Its top is about 6,500 feet (1,980 meters) below the ocean surface today"