Günter, on Monday 02 December 2013, raised the interesting question of the difference between rubble and wreckage.

To answer that fully and to check the meanings more precisely so I was sure of myself I did some quick searches on www.duckduckgo.com.

Remember to do good searches remember that the search engines give priority to the first three words so in this case my searches were first rubble meaning and then wreckage meaning

Here are a portion of the results:

rubble (rŭbˈəl)

• n. A loose mass of angular fragments of rock or masonry crumbled by natural or human forces.
• n. Irregular fragments or pieces of rock used in masonry.
• n. The masonry made with such rocks.

and

wreckage (rĕkˈĭj)

• (noun) The act of wrecking or the state of being wrecked.
• (noun) Something wrecked.
• (noun) The debris of something wrecked.

along with a lot more information – you can see that rubble is the result of rock / masonry so by extension applies to buildings and wreckage implies that something has been wrecked or is a wreck like a ship, a car or a plane.

I hope that clarifies the situation.