[[Image:240px-Epicenter&Hypocenter.png|240px|thumb|کانون ژرفی در جایگاه رخداد [[زمینلرزه]] و زیر [[مرکز سطحی زمینلرزه]] در رویهٔ زمین، قرار گرفته است.]]
کانون ژرفی یا کانون زمینلرزه (به انگلیسی ''hypocenter'' یا ''seismic focus'')
An earthquake's hypocenter, the position where the [[Strain (materials science)|strain]] energy stored in the rock is first released, marking the point where the [[fault (geology)|fault]] begins to rupture. This occurs at the focal depth below the [[epicentre]].
The focal depth can be calculated from measurements based on [[seismic wave]] phenomena. As with all [[wave]] phenomena in [[physics]], there is uncertainty in such measurements that grows with the [[wavelength]] so the focal depth of the source of these long-wavelength (low frequency) waves is difficult to determine exactly. Very strong earthquakes radiate a large fraction of their released energy in seismic waves with very long wavelengths and therefore a stronger earthquake involves the release of energy from a larger mass of rock.