The earth's crust is made up of different tectonic plates that are constantly moving over the mantle. This process provides for the encounter between different tectonic plates that cause physical changes in the crust, such as, for example, the formation of mountains.
In the western portion of the United States, more precisely in the state of California, there is a tangential movement between two tectonic plates (the plate American plate and the Pacific plate), the first slides 14 millimeters per year in a southeast direction, while the Pacific plate moves 5 millimeters in the direction opposite of the first. This movement of plates generated one of the most famous faults on the planet, the San Andreas. The friction between these two plates generates frequent earthquakes in the region, making California one of the areas of greatest tectonic instability on the planet.
The West Coast of the USA, especially California, is one of the places with the greatest seismic activity on the planet. The San Andreas Fault is a gigantic visible crack approximately 1,300 kilometers long that marks the boundaries between the two largest tectonic plates on the planet: the North American plate and the North plate Pacific. The landslide between the plates causes great instability throughout the state of California, and was the main cause of the violent earthquake that shook the city of San Francisco in 1906.
According to the Geological Research Institute of the United States, the state of California has a 99% chance of being hit, in the next three decades, by an earthquake exceeding 6.7 degrees.
By Wagner de Cerqueira and Francisco
Graduated in Geography
Source: Brazil School - https://brasilescola.uol.com.br/geografia/falha-san-andreas.htm
