Roberta Olsen, age 10, of Rowayton, Connecticut, for her question:
How were the Hawaiian Islands formed?
The planet earth never stops remodeling its geography. The major work goes on slowly; very slowly. Inch by inch, through countless ages, massive mountains arise and wear down. Even the big sturdy continents gradually creep around the globe. These changes occur in the restless, rocky crust. And most of the global crust is down below oceans of sea water. The formation of the Hawaiian Islands began in the deep sea bed below the Pacific.
This geography story started who knows how many millions of years ago. Even if there had been people around at that time, they would not have noticed it. For it began below three miles of sea water, way out there near the center of the vast North Pacific Ocean. The seabed erupted and left a pile of ashes and volcanic lava. Perhaps the eruption triggered a tidal wave that swept outward for hundreds of miles and doused the distant shores. But no people were there to notice it.
This first volcano was born in a weak, restless region of the earth's crust, deep under the sea. Others erupted and in time it had a row of neighbors. Time after time these volcanoes erupted and each time their piles of lava grew bigger. Gradually they grew a mile, then two miles and three miles high. At last they were tall enough to reach the surface.
The sunlit surface teemed with sea creatures. Some of them crusted the underwater slopes with stoney corals. After a few more eruptions, first one, then another volcano lifted its peak above the water and islands were born. Time after time, the winds, the rains and the pounding waves tried to smash them back down. But each time they grew taller and at last, the new islands were tall enough to stand securely out there in the lonely ocean.
These were the western islands of Hawaii. As they grew, other volcanoes began erupting from the sea bed. Gradually, one by one they formed a long chain of islands toward the southeast. Their volcanoes erupted masses of lava from deep down in the earth's crust, and all the islands grew bigger. But at last, the oldest volcanoes on the western islands grew old and died. Then the winds, the rains and the pounding waves wore down their slopes. Now these older islands at the western end of the chain are little islets of sand and coral.
Toward the southeast end of the chain, some of the younger islands still have active volcanoes. They still are growing too fast for the waves and weather to wear them down. But all the Hawaiian Islands large and small, young and old are massive volcanic mountains, standing on the sea bed three miles or more below the surface.
The birth of an ocean island is a great event and from far away, other dry lands send gifts to the new arrival. Coconuts wash up on its shores, take root and become trees. The winds bring seeds, spores and perhaps a few insects. Perhaps a few small animals, drifting on floating logs; get shipwrecked on the shores. Globe traveling birds bring seeds and other small gifts. It took millions of years for each island to climb above the water. But in only 50 years or so, its dry land is clothed in green plants and populated with animals from afar.