Why are earthquakes shallow?

Question

using the concepts of elastic and ductile deformation

Answer 1

Earth quakes are created by the sudden slip of tectonic plates. The tectonic plates are moving at the rate of about 50 to 100 mm per year due to the convection of heat under those plates at asthenosphere. The earthquake depth may vary from 5 k/m to even 450 k/m at some places.It depends upon the thickness of tectonic plate at that area. Visit my site to see the earth section.

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Answer 2

waiting for food

Answer 3

Earthquakes are not always shallow.  They seem that way because they became strong enough to produce surface waves.  What you are feeling are the surface waves.

Answer 4

Not all Earthquakes are shallow, but the most powerful are. This is because at depth, where the rock is hotter, the rocks can more easily pass each other and dissipate pressure by ductile flow.

At shallower depths, where the rock is cool, are plates try to pass each other, they are rigid and so fracture or release pressure elastically  in a single event. This is an Earthquake.