What does an earthquake do?

Answer 1

1. they shake the ground ... up and down or sidewise

2. the relieve the internal pressure that builds up as the tectonic plates move.

Here effects of an earthquakes: Tsunami A tsunami is a series of huge waves caused by an earthquake under the sea. These waves travel at about 800 km per hour. Before a tsunami reaches the shore, it slows down. The water along the shore recedes as if there were a very low tide. When the water comes back, the height of its waves may reach up to 30 m. It can destroy houses, crops and people as it goes inland and then back to the sea. Seiche An underwater earthquake can also generate a big wave in an enclosed body of water like a lake or a pond. This big wave which can be about 3 m high is called a seiche. A seiche can cause immediate flooding of areas near the lake. Faulting Strong earthquakes can also change the earth's surface. Cracks may form on the crust. When this happens, part of the crust may be displaced horizontally or vertically. In some cases, a section of the crust is raised above the section near it. Shallow gaps may also be formed on the crudt. Landslide Some earthquakes affect hilly or mountainous areas. Continiuous shaking of the ground changes the psition of some rocks or dislodges them. When these rocks roll downhill, they can destroy houses on their path or kill people. Sand Blows When an earthquake occurs in a place where there is much ground water, water is forced out of the ground in the form of an earthquake fountain. When this happens, sand is forced out and deposited on the ground in the form of volcanolike mounds. These are called sand blows. Fire Earthquakes can also cause fire. This happens when electric wires are destroyed and electric posts are upturned. Fire can easily spread to residential houses and other buildings.