What is the basis of God's Goodness/Righteousness?

I would like an Answer from a Reformed/Calvinist Perspective. There are many instances in scripture that affirm GOD is good (Psalm 119:68, 1 Tim 4:4). And that God is Righteous (Psalm 48:10, Jeremiah 12:1). I was considering God's Sovereignty - that all things move according to his will. Which means, earthquakes, disease, death etc... And he has the right to - for example, Kill a person, because all people are his possessions. So a person sins if he kills another person because he has no right to the lives of other people. But if a person were to kill a character in his/her books - is is not a sin, since the author has the right to do whatever he wants in his book. Because God owns all the earth, he has all rights to do whatever he wants. And cannot be guilty of sin- since there are no bounds for him to overstep. This is the only way I have thought of to reconcile 'God is Good' and 'God caused the earthquake'. However, If I was an author who killed a character in my book - you would not necessarily regard it as a 'good' action, just that the author cannot be condemned for it. So is the Righteousness of God based on the nature of his position over the world? or is God just defined as Righteous. Thanks.