Reply #7: My theory is that..

[SnoopDog]

the polar caps are melting significantly. With the melting, the consolidation of ice, and therefore the weight of the ice, is being removed. With the weight of the ice no longer at the polls, the tectonic plates are seeking equilibrium. Therefore more and larger earthquakes.

Over millions of years (or hundreds of thousands of years), the polar caps have accumulated ice. The weight of the ice exerts a force and in those days I imagine many earthquakes happened as well. In recent times, things basically achieved a 'steady-state'. Not earthquake free obviously but a basic equilibrium of tectonic plate movement held in check by the polar caps. Now, that ice is melting, weight being reduced, - allows for more movement.

I picture it as a balloon (not a great analogy but it my might work): blow up a balloon. At the top and the bottom, with your hands, push down at the 'poles'. The middle gets pushed out. Now release your hands - the middle bulge moves back into position.

Edit:
Global Warming/Climate Change just doing its 'thing'.