The tectonic plates of power are moving.

「世界のパワー構造を覆う巨大な岩板であるプレートが動きつつある」。

tectonic platesは、「地球の表面を覆っているプレートと呼ばれる何枚かの巨大な岩板」のことですが、ここでは比喩的に「ある構造を構成している要素」という意味で使われています。The tectonic plates of 〜として、〜に別の名詞を入れて応用してもいいですね。

例文は、BBCの記事、'US and China: Powerplays and mistrust' By Damian Grammaticasからです。

'The United States and China, West and East, the superpower and its rising rival.

There are countless ways of characterising the relationship between these two nations, but almost every one is animated by the idea that we are witnessing an historic shift. The tectonic plates of power are moving, and the results are unpredictable.

So the eve of Hu Jintao's state visit to America seems a pretty fortuitous place to begin what aims to be an occasional column from China.

How the future balance between Washington and Beijing plays out will go far in shaping the world in the coming decades. Will these two be friends or enemies? Will they be rivals or partners?

Will they co-operate or find themselves in conflict? The answer could have far-reaching effects on all our lives.'

ちなみに、fortuitousは、「偶然の、思いがけない」という意味の形容詞です。

続きはBBCのサイトで。