In their literal meanings, "to run away" means exactly to run away. "to get away" is a little more vague. It means to escape. But it can be done by running/driving/flying/etc. In more abstract meanings, "to run away" can mean to escape. e.g. "you can't run away from your problems. You have to face them!" "to get away" still means to escape. e.g. "let's get away from the bustle of the city and go somewhere peaceful." Take note however, that "to get away" when used in some contexts, can have a different meaning from "escape" e.g. "You're covered in mud. Get away from me! (this is asking that person to GO AWAY from you, not to escape from you)

No. To "run away" is to be in the process of fleeing something. To "get away" is the state of having fled something. Or, if you will: If you are running away, you're still doing it. If you have gotten away, you succeeded in escaping.