RECEDED> To go or move away; retreat; go to or toward a more distant point; withdraw.
Here John sees the sky being what is referred to as Receded , it appears the sky has changed and the every Mountain and Island moved from its previous position, this could have something to do with the Great Earthquake mentioned earlier in this paragraph
We had a wonderful lighting show here in Leavenworth the other night. The sky over the western side of the Village , over the Cascade Mountians was blue and cloudy , but in the eastern sky the scene was quite different . grey skys with abundant lighting strikes and a beautiful rainbow surrounded by pink sky right in the middle of it all . It was breathtakingly beautiful as you moved your eyes around from east to west . As we read about the Great Earthquake earlier in verse 6 , I can imagine earth landscape to be forever changed as we see here in this verse .
The picture I used for todays reading is a sunset on the beach at a town called Seaside Oregon, it was so beautiful and colorful . Enjoy !