Spreading centers have shallow earthquakes, while trenches have deep earthquakes.
Earthquake is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip, or by volcanic or magmatic activity, or other sudden stress changes in the earth
simply An earthquake is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves.
mainly Shallow earthquakes are between 0 and 70 km deep and are mainly associated with mid-ocean ridges, with mountain ranges in the interior of the continents of Europe and Asia, and with the mountains and ocean trenches that surround the Pacific Ocean.
The immediate cause of most shallow earthquakes is the sudden release of stress along a fault rupture (crack) in the earth's crust.
