how do earthquakes start?

Answer 1

interplate or intraplate earthquakes?

Most commonly earthquakes are caused by plates moving relative to each other. There are 3 types of plate movement.

1) convergent
2) divergent
3) transform

1) plates move together, this caused ruptures, folds etc in the rocks causing seismic waves

2) As plates move apart, new rock comes up, causes displacement, sending out seismic waves

3) plates slide past each other causing seismic waves,

Answer 2

AS HAS BEEN ANSWERED THERE ARE THREE WAYS I WILL DEAL WITH THE WAY WHICH CAUSES THE MOST VIOLENT EARTHQUAKES. AS TECTONIC PLATES SLIDE PAST OR UNDER ANOTHER THERE COMES A TIME WHEN A "HANGUP" OCCURS AND AS THE FORCE PUSHING BUILDS UP IT STORES KINETIC ENERGY. THIS CONTINUES TO BUILD UNTIL THE FORCE BECOMES GREATER THAN THE HANG UP AND THE PLATE MOVES OR SUBMERGES AT ONCE ALL THE MOVEMENT THAT SHOULD HAVE OCCURRED OVER THE "HANGUP" TIME RELEASING ENORMOUS AMOUNTS OF KINETIC ENERGY AND RESULTING IN MOVEMENTS OF AS MUCH AS 25 OR MORE FEET AT ONCE.DEPENDING ON WHERE THE EPICENTER IS LOCATED IT CAN CAUSE ENORMOUS DAMAGE. CONSIDER THE SAN FRANCISCO QUAKE OF 1906 OR THE ONE IN THE MID 1990'S. ESPECIALLY CONSIDER THE SERIES OF QUAKES ALONG THE NEW MADRID FAULT IN 1811-12.

Answer 3

Amazing, Im working on an assignment about this right now. Its for Marine Science :)

The Earth is made up of plates, which look like this:

http://www.windows.ucar.edu/earth/images/earth_plates_usgs_L.jpg

http://www.dkimages.com/discover/previews/1244/597340.JPG

See the red stuff in the second image? That stuff is moving around all the time, which moves the plates. When the plates move, they sometimes force other plates to slide beside them, or to slide under or above them. When doing so, that is an earthquake.

http://www.ce.washington.edu/~liquefaction/selectpiclique/kobe95/expressway.jpg

http://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Chuetsu_earthquake-earthquake_liquefaction1.jpg/799px-Chuetsu_earthquake-earthquake_liquefaction1.jpg

Imagine the plates as puzzle pieces, all forming together.

Answer 4

My science teacher says the plates get "stuck" and build up pressure. They keep building pressure over years and then when the rock finally moves it makes a whole lot of damage which what you see in pics.

Hope i helped.