Why are there earthquakes?

Answer 1

Most of the stresses that cause earthquakes can be explained by the theory of plate tectonics.

Answer 2

We have earthquakes because of plate movement. There are several types of plate movements.

1. Divergence/Divergence: where two plates move away from each other. Like in the Atlantic Ocean.

2. Transform fault: This is like the San Andreas fault in California. Transform faults slide past each other in opposite directions.

3. Continent/Continent: An example of this is the African and Indian plates. The result of theses 2 plates bumping into each other is the Himalayan Mountain Range, which continues to grow this very day.

4. Oceanic/Continental: This is when the ocean floor subducts under the continental plate. As a result magma rises to the crust and forms volcanoes. For example, the Hawaiian Islands. This is also a good example of the "pacific ring of fire."

Also, earthquakes can be caused by explosions and things in that area.

There are some I missed I think, but these are some good examples of what creates earthquakes. If you need more info contact me at my 360.

Answer 3

Actually, noone here is quite right. Ultimately, the movement of the Earth's tectonic plates are what makes earthquakes happen - but the actual shaking is more complex than you'd think.

For simplicity, assume earthquakes can only occur where there are already faults. When stress builds up along a fault, the rocks either side are strained (deformed) gradually. Eventually, the stress on the fault exceeds the frictional strength and the rocks either side of the fault move past each other. When this happens, a lot of the stress is released. The rocks are able to elastically rebound to how they were before stress built up. It is the elastic rebound which causes seismic waves.

Earthquakes are the surface expression of seismic waves, or put another way, the product of surface waves.

Answer 4

Most of the earthquakes happen because of the tectonic plates movement.But,it could be caused an earthquake by the falling of rocks to a big cave which exist underneath a location.

Answer 5

To the point: The earth's plates are always moving. Either into each other, or breaking apart from itself and cause pressure. Thus- earthquakes start.

Answer 6

Because molten substance rises from the inner earth. The movement of the molten substance shifts the relative thin surface which 'floats' on the molten substance.
The heat within the earth is thought to be a leftover from billion years ago. Others think there's thermonuclear activity or even fusion in the inner earth.

Answer 7

There are numerous reasons why earthquakes occur, it can be due to..

--Volcanic Erruptions
--Sudden Movement of the tectonic plates in the pacific ocean
--Soil Errosion.
--Land Instability.

Hope this helps you out.

Answer 8

its called plate tectonics, the earth is made up of many plates of surface crust, and they are always moving one way or another, usually when one moves violently and catches on another plate thats called an earthquake

Answer 9

Parts of the Earth always in motion. This can cause stresses which after they build up significantly can move tectonic plates.

Answer 10

because it shakes...lol

there are plates in the earth crust and sometimes it shifts due to certain preassure either from above or gas inside making the surface above it move or shake causing displacement both under and above.