National Geographic : 1954 Jan
Myojin Lifts a Shattered Dome of Water, Steam, and Ash, Then a Mushroom Cloud The sea was calm on September 23 when Shinyo Maru, another Japanese research vessel, arrived off Myojin. Suddenly a black, angry dome arched out of the water five miles ahead. A second ex plosion occurred when the ship was a mile away. Prof. H. Niino of the Tokyo College of Fish eries requested the crew to go forward to pick up pieces of floating pumice, an exploded lava so honeycombed with gas spaces that it becomes buoyant. As he lowered a dip net over the rail, the sea welled up several hundred yards ahead. "In the next moment," he recalled, "the swell looked like a boil on the surface. Then it bloomed, like a monstrous flower, 20 feet high and 600 feet across. Instantly water began to fall like a cata ract while the dome's center pushed up to a height of 100 feet. "Suddenly a black mass burst out from the dome's right side. Volcanic bombs (incandescent chunks of lava) sailed into the sky. Steam from the lower part of the cloud swirled across the sea to meet the boat. Hot pumice fell like rain, hiss ing as it dropped into the water." The explosion filled the air with a roar. Air borne concussions buffeted the crew. Shinyo Maru retreated at full speed. A wave like a tidal bore's overtook the ship and tossed her like a canoe in rapids. A small part of the ocean around Myojin may have been composed of new or "juvenile" water just liberated from the earth's interior. Some sci entists believe that such water, squeezed out bil lions of years ago when the crust began to cool, created the oceans and built them to their present levels. New waters from volcanoes increase the sea's volume yearly. These pictures were taken as Shinyo Maru stood five miles from Myojin. Top: Fifty seconds old, the cloud spreads across 1.500 feet. Lower: Five minutes later the initial blast is spent. Surface winds rushing into the partial vacuum lift the cloud skyward to an even tual 15,000 feet. Unseen by the camera, an under ground chamber stands open. Molten rock spews out, boils the sea water, and feeds steam into the cloud.