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1 What makes the tectonic plates of the Earth's crust move?

Scientists believe that one of the primary forces behind plate movement is thermal convection. Thermal convection is when heat from the core of the Earth is transferred to the surface of the Earth by the mantle. The mantle is the thick, mostly solid layer of the Earth between the crust and the core. Thermal convection works a lot like a pot of boiling water. Liquid rock near the mantle is heated and rises toward the crust. The rock near the surface is cooler and sinks back down toward the core. This forms the same type of convection current that causes the plates to move.

2. Is the Earth solid or liquid?

The Earth has both solid and liquid components, but it is mostly solid. The Earth's interior is composed of four layers, three solid and one liquid — not magma but molten metal, nearly as hot as the surface of the sun.

3. How hot is the center of the Earth?

Scientists have determined the temperature near the Earth's centre to be 6000 degrees Celsius.

4. What kind of earthquakes do you know?

There are two main types of earthquakes: natural and man-made. Naturally occurring earthquakes occur along tectonic plate lines while man-made earthquakes are always related to explosions detonated by man.

Sometimes people distinguish four different types of earthquakes: tectonic, volcanic, collapse and explosion.

    A tectonic earthquake occurs when the earth's crust breaks due to geological forces on rocks and adjoining plates that cause physical and chemical changes.

   A volcanic earthquake is any earthquake that results from tectonic forces which occur in conjunction with volcanic activity.

   Collapse earthquakes are small earthquakes in underground caverns and mines that are caused by seismic waves produced from the explosion of rock on the surface.

   An explosion earthquake is an earthquake that is the result of the detonation of a nuclear and/or chemical device.