The epicentre is NOT "bang in the middle". It's the point on the Earth's surface directly above the centre (focus) of the earthquake; hence it is, by definition, not at the centre.
Towards the end of last year I heard an announcer on Radio4 reporting an earthquake. She said "the epicentre..........." and I thought "at last, the chance to use the word correctly", then she continued "...was 5km below the surface".