The Earth’s crust consists of seven giant lithospheric plates and diverse smaller plates. These plates move towards one another (a focussed boundary), apart (a divergent boundary) or past one another (a remodel boundary)
Earthquakes square measure caused by a sharp unharness of stress on faults within the layer. the continual motion of tectonic plates causes a gentle build-up of pressure within the rock strata on either side of a fault till the strain is sufficiently nice that it’s discharged in a very sharp, jerky movement. The ensuing waves of unstable energy propagate through the bottom and over its surface, inflicting the shaking we have a tendency to understand as earthquakes.
Earthquakes caused by plate tectonics are called tectonic quakes. They account for most earthquakes worldwide and usually occur at the boundaries of tectonic plates.
Induced quakes are caused by human activity, like tunnel construction, filling reservoirs and implementing geothermal or fracking projects.
Volcanic quakes are associated with active volcanism. They are generally not as powerful as tectonic quakes and often occur relatively near the surface. Consequently, they are usually only felt in the vicinity of the hypocentre.