Scientists say the Pacific plate is moving toward the northwest, while the North American plate is moving more to the southeast. Where these two huge plates come together is called a fault line.
The name of this line between the plates in California is the San Andreas Fault. It is along or near this line that most of California's earthquakes take place, as the two tectonic plates move in different directions.
The city of Los Angeles in Southern California is about fifty kilometers from the San Andreas Fault. Many smaller fault lines can be found throughout the area around Los Angeles. A major earthquake in nineteen ninety-four was centered along one of these smaller fault lines.
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VOICE TWO:
The story of plate tectonics begins with the German scientist Alfred Wegener in the early part of the twentieth century. He first proposed that the continents had moved and were still moving.
He said the idea came to him when he observed that the coasts of South America and Africa could fit together like two pieces of a puzzle. He proposed that the two continents might have been one, then split apart.
Later, Alfred Wegener said the continents had once been part of a huge area of land he called Pangaea. He said the huge continent had split more than two hundred million years ago. He said the pieces were still floating apart.
VOICE ONE:
Wegener investigated the idea that continents move. He pointed out a line of mountains that appears from east to west in South Africa. Then he pointed out another line of mountains that looks almost exactly the same in Argentina, on the other side of the Atlantic Ocean. He found fossil remains of the same kind of an early plant in areas of Africa, South America, India, Australia and even Antarctica.
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2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25