Grease a 9 x 13 x 2 cake pan. Cover the bottom of the pan with the pecans and the coconut.
Prepare the German chocolate cake mix according to box directions.
Pour cake batter over coconut and pecans. Melt the butter together with the cream cheese in a saucepan. Stir in the powdered sugar and stir while cooking--this mixture scorches easily so use low heat. Pour this mixture on top of the cake batter. Bake at 350 degrees for 45-60 minutes. Test with a toothpick for doneness.
When you remove it from the oven it will have a large crack in the middle -- that's why it's called Earthquake Cake.