Eileen Walter, age 12, of Milwaukee, Wisconsin, for her question:

Can the sea floor erupt as the land does?

Compared with tine seabed, the land is calm and almost motionless. The fact that enormous eruptions go on under the ocean has been discovered only during the past two decades. The news shook the whole world of science and experts had trouble getting used to the upsetting idea. Now they are probing for patterns that reveal how the seabed erupts and what this does to global geography.

On the world map, we notice that the two sides of the Atlantic Ocean resemble parts of a giant jigsaw puzzle. Loop, ago, it was suggested that these and perhaps other continents once were joined together and then drifted apart. Most earth scientists pooh poohed this theory because nobody could figure out how the oceans and continents could move around and remodel the map. Then in 1956, marine researchers took a more profound look at some startling events on the ocean floor.

Already some 40,000 miles of massive submerged mountain ridges and ranges and been charted through the world oceans. The new look revealed that these ridges are far from calm. In fact, they are enormous cracks in the solid crust, where masses of molten lava erupt up from below. These undersea eruptions out perform all the volcanos on the dry land. It now is thought that the total crust is made of huge slabs called tectonic plates, fitted together in a global shell. The undersea eruptions occur along the cracks between these plates.

At present, we cannot estimate the enormous amount of material that erupts from below the seabeds. But obviously the lava piles up the mid ocean ridges. And the growing evidence suggests that it also forms new crustal material that pushes the plates apart. All the sea beds are spreading, pushing, outward from the mid ocean ridges cohere these underwater eruptions are occurring.

As the seabed spreads along a crack down the mid Atlantic, obviously it is pushing the map of the New World farther from Europe and Africa. This explained how land masses can drift around the globe and made it possible for earth scientists to believe the old theory of drifting continents. Every year, researchers find more evidence to prove that this really is happening in the global map occur very, very slowly. But they have been traced back through millions of years to a time when all the land apparently was in one continent.

The next problem is to find out what causes this spreading to happen, host experts agree that the needed energy comes from convection currents, deep down below the crust in the plastic mantle,layer. The erupting ridges most likely are the result of rising heat currents. Other evidence suggests that these are the result of descending currents, thousands of miles away, near lines of plunging trenches in the ocean floor.