Question

What is the driving force behind plate tectonics?

Answer 1

Hint: The lithosphere is divided into several tectonic plates. These plates are a part of a thermal convection system.

Complete answer:
Plate tectonics is a scientific theory that describes how the large tectonic plates that make up the lithosphere of the Earth move and interact with each other.
Thus, we can also say that the tectonic plates are afloat on an ocean of magma.

There are 7 major plates and numerous minor and microplates. The major plates are;
1. African plate
2. Antarctic plate
3. Eurasian plate
4. Indo-Australian plate (Indian Plate + Australian Plate)
5. North American plate
6. Pacific Plate
7. South American plate
These plates cover both the continents and the ocean. While the continental plates are 200 kilometers thick, the oceanic plates are much thinner and are 50km to 100km thick.

We know that the Earth has three main layers in itself. The outermost layer is the crust or the lithosphere. The middle layer is the Mantle. The innermost layer is the core, which is also half liquid and half solid.

The outer or the liquid part of the mantle contains molten metals and is called lava or magma. It is the heat dissipated from this extremely hot mantle that is acknowledged as the driving force behind the plate tectonics. This heat creates convection currents through the liquid and semi-liquid parts of the earth. These currents in turn create upward pressure on the tectonic plates of the Earth, and hence the motion of these plates.

Note: The Juan de Fuca Plate is the smallest tectonic plate and is 2,50,000 square kilometers in area. The Pacific Plate is the largest tectonic plate and is 10,33,00,000 square kilometers in area.