Earthquakes

5 Pages 1255 Words

Until the 18th century, earthquakes were thought to be caused by air rushing out of caverns deep in the Earth's interior (Watson). But we all know that is not how an earthquake happens. The earth’s surface is broken into seven large plates (“Major plates in the world”). There are also many other little plates on the surface but seven main ones. Each one of these plates is approximately 50 miles thick and moves against each other a few inches a year (USGS). The seven main plates in the world are: Eurasian plate, Pacific plate, North American plate, Nazca plate, South American plate, Australian plate, and Antarctic plate (Major plates in the world). When the plates move against each other, it’s not just your average plate rubbing. There are three different types of movements at the boundaries of the plates: convergent, divergent and transform-fault (“Major plates in the world”).
A convergent movement is when plates move tword each other and colide. An example is when an oceanic plate collides with a continental plate. The oceanic plate slides under the continental plate making a huge ocean trench. This is called a subduction and you can find it where the Nazca plate and the continental Sout American plate (“Major plates in the world”). When continental plates collide, they form new major mountain systems such as the Himalyans (Watson). A divergent movement is when plates move away from each other. The mid-Atlantic ridge is from a divergent movement (“Major plates int the world”). When plates diverge, hot molten rock rises, cools, and fills in the emty spaces adding new formation to the edges of the oceanic plates (Watson). This is also known as sea-floor spreading. (“Major plates in the world”). A transform movement is when two plates move horizontal on each other A perfect example of this is the San Andreas fault (“Major plates in the world”). Los Angelas lies on the Pacific plate and is slowly moving...