Why would earthquakes occur at depths of over 700 kilometers?

If it is intermediate or deep below the crust-between 70 and 700 km (40 and 400 mi) deep-a deep-focus earthquake will be produced. More.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.