The surface directly above where an earthquake starts is called the epicenter, according to the United States Geological Survey. The location of the earthquake's origin is the fault or fault plane, and that is the place where two pieces of Earth move past each other, causing the ground to shake.
The fault plane is often miles below Earth's surface, according to the USGS. The surface below the fault is called the hypocenter. Scientists use seismographs to measure the intensity of an earthquake. Three seismographs placed in different locations are used to triangulate the earthquake's starting position, which reveals the location of the epicenter.