Early on the morning of November 14, 1963, a small fishing boat was sailing off the south coast of Iceland. The boat's cook, Olafur Vestmann, noticed a plume of dark smoke far on the horizon as dawn broke on the sea. At first he was alarmed, because he thought that another boat might be on fire. But when he called the other fishermen on the boat, they soon realized that the plume of smoke was not from a fire. It was a black column of volcanic ash. A volcano was erupting from beneath the sea. By 11:30 A.M., the eruption was in full force. In Volcanoes, Barbara and Robert Decker describe the eruption: Explosions from the vents [on the ocean floor] were occurring every few seconds, shooting jets of dense black ash to heights of 100 to 150 meters. By 3:00 P.M. the separate...