Plate tectonics is a scientific theory that explains the structure and movement of the Earth's lithosphere, which is the rigid outer layer of the Earth. According to this theory, the lithosphere is divided into several large and rigid plates, known as tectonic plates, which float on the semi-fluid asthenosphere beneath them.
These tectonic plates interact at their boundaries, leading to various geological phenomena. There are three main types of plate boundaries:
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Divergent Boundaries: Here, two tectonic plates move away from each other. This movement can create new oceanic crust as magma rises to the surface, commonly seen at mid-ocean ridges.
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Convergent Boundaries: At these boundaries, two plates move toward each other. This can result in one plate being forced beneath another in a process called subduction, leading to the formation of mountain ranges, earthquakes, and volcanic activity.
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Transform Boundaries: In these areas, two plates slide past one another horizontally. This lateral movement can cause significant friction and lead to earthquakes, such as those that occur along the San Andreas Fault in California.
The theory of plate tectonics not only explains the distribution of earthquakes and volcanoes but also provides insights into the formation of continents and ocean basins, continental drift, and the geological evolution of the Earth over millions of years. It is fundamental to our understanding of Earth's geology and the processes that shape its surface.