William Sager’s 20-year hunch has paid off in a very big way.
In September, the University of Houston geophysicist and his team announced that Tamu Massif, an underwater volcano about a third of the way from Japan to Hawaii, is by far the largest volcano on the planet.
For two decades, using sonar and other undersea mapping methods, Sager has been studying an oceanic plateau in the northwestern Pacific called Shatsky Rise. Over several expeditions, he began to suspect that the subtly dome-shaped formation at Shatsky’s south end, which he named Tamu Massif, might be an enormous volcano.
To confirm his theory, Sager’s team drilled core samples and bounced seismic waves through Tamu’s layers to determine its composition. They discovered Tamu’s 120,000 square miles were made of massive lava sheets, up to 75 feet thick, that had erupted from a single summit about 145 million years ago.
In square miles, ...
