an earthquake happens when to of the earth's giant plats suddenly slip past each other, snap ,crack or make other rapid movement.

this is what happens after a earthquake.

An earthquake can last for just a few seconds - and might not do to much damage- but could last for several minutes .Vilontly

shaking for several minutes , or a series of shorter, more powerful shaking, can cause even the tallest sky scraper or the strongest bridge to collapse.