- Beneath the Surface
- Plate Borders & Mountain-Building
- Plate Borders & Earthquakes
- The Ring of Fire
- More Earthquakes, But Why No Tsunamis?
- The Asian Tsunami in Sri Lanka: A Personal Experience
- Geologic History of the Earth (animation)
- Plate Boundary Interactions (animation)
- Earthquake Epicenters (animation)
- The Asian Tsunami, 26 December 2004 (animation)
- Tsunami Simulator (animation)
- Glossary & References
The Earth A Living Planet
Earth is a living planet. Activity is constantly taking place not only on the surface, but also on the inside beneath our feet. We do not know exactly how our planet works. Compared to the age of the universe, the amount of time we have studied the Earth is very short. We do have theories about how continents form and change, but the scope of testing such theories is far too broad to be realistic. We continue to study evidence, but are not able to prove any theories beyond a doubt.
The coastlines of Africa and South America fit together like pieces of a jigsaw puzzle. This is one of many pieces of evidence to support the theory of continental drift.
Throughout history, several theories have tried to explain the behavior and evolution of the Earth. The most convincing of these, widely supported by scientists, is the plate tectonics theory.
Click on the image to see an animated history of the earth from 600,000,000 years ago to 200,000,000 years into the future.
Alfred Wegener, a German geologist and meteorologist, studied the close fit between the coastlines of Africa and South America. He observed that fossils were similar on both sides of the Atlantic. In 1912, he proposed the theory of continental drift. According to his theory, the two continents were once joined together.
Over the following years, the theory of continental drift was refined to become the theory of plate tectonics. Scientists studied how plant and animal fossils are dispersed throughout the world. They learned more about the nature of the ocean floor and distribution of volcanoes and earthquakes. They gained new information about Earth’s ancient magnetism and the flow of heat from the interior of the Earth.