When the Lamb broke the sixth seal, John looked and saw (and may have experienced) a great earthquake. There have been many earthquakes recorded in the bible, and many more in this present day. But this one and also the one at the very end of the Tribulation (Rev. 16:18) will be the greatest in world history. In fact, they will be more than earthquakes. MacArthur writes, “All the earth’s faults will begin to fracture simultaneously, resulting in a cataclysmic, global earthquake.”
Another author, Hal Lindsey, in his commentary of Revelation, There’s A New World Coming, says of this passage that this quake will be “the granddaddy of them all.”
And he believes, because of the description here (verses 12-14), that the quake will be set off by a nuclear explosion. Lindsey comments particularly on verse fourteen:
Do you know what happens in a nuclear explosion? The atmosphere rolls back on itself! It’s this tremendous rush of air back into the vacuum that causes much of the destruction of a nuclear explosion. John’s words in this verse are a perfect picture of an all-out nuclear exchange.
It is also quite obvious that, whereas the judgments in the first four seals were by human jurisdiction; from this seal onward, they will come to the earth directly by God through nature. With that being said, we must believe that God can use any means He wants to move the heavens and the earth, whether by nuclear power or by a single word.
The results of the earthquake. Here are four results from this great quake:
1. Ash in the atmosphere. There is no doubt that this great, global earthquake will result in many volcanic eruptions where ash and debris will be blown into the earth’s atmosphere, blocking the sun and giving the moon a blood-red color. I imagine that the entire earth will be quite dark and eerie and also loud with volcanic eruptions.
2. Asteroid or meteor showers. Most bible scholars take the reading “stars” to mean any celestial body, and the meaning here would suggest asteroid or meteor showers. This phenomenon would be dramatic and dangerous, especially if they strike the earth, which I think many will.
3. The sky will split apart like a scroll. We don’t know the details of what will happen, but it seems that the earth’s atmosphere will be dramatically changed and the sky as we know it will be rolled up and disappear.
4. Every mountain and island will be moved. Here it is apparent that the earthquake will so shake the globe that great segments of the earth will be moved around. In the last great quake of the Tribulation (Rev. 16:20) we read that “every island fled away, and the mountains were not found.” So it seems that the quake here in this sixth seal will be the first stage of what will eventually happen to the earth. Here the earth is cracked open or loosened up; later, at the end of the Tribulation the earth will be radically changed, pretty much flattened in preparation of the Millennial kingdom.
How people will respond
Everyone on earth, from the greatest to the lowliest, will be terrified—mostly of the presence of God. They will have an acute awareness of His presence and His wrath against them; so much so that they will hide themselves in caves and among the rocks of the mountains—or any place they can find to be safe. And because they will not be able to be comforted, they will pray to the rocks to fall on them and hide them. It is interesting that they will wish and pray not so much to be saved from all the cataclysmic events, but from God—from His terrible, wrathful presence. And they will wonder who, if any will be able to survive His great wrath.
 John MacArthur, John MacArthur’s notes of Revelation 6:12-17.
 Hal Lindsey, There’s A New World Coming (Vision House Publishers: Santa Ana, California) 1973, p. 94.
 Ibid., p. 95.