Nearly 200,000 people in Southern California felt shaking after hundreds of earthquakes rattled the Imperial County desert over the weekend, with the strongest earthquake reported as a magnitude 4.7.

A 2.7 magnitude micro earthquake occurred near Brawley, California on Saturday evening, with the shake being felt in nearby areas such as Westmorland, Imperial, Calipatria and El Centro.

Earthquakes usually occur along fracture zones in Earth's crust, where large tectonic plates slide past one another and become locked. Stress builds up over long periods and is suddenly released in the form of an earthquake.