The final event:
Back to Revelation 16:21
21 And there fell upon men a great hail out of heaven, every stone about the weight of a talent: and men blasphemed God because of the plague of the hail; for the plague thereof was exceeding great.
The Holy Bible : King James Version. 1995 (Re 16:20). Oak Harbor, WA: Logos Research Systems, Inc.

How would this event of an earthquake result in a great hail of stones? First off notice that people still survive because they are blaspheming God for the plague of the hail. If the mountains were shaken flat as mentioned at the beginning of this article, the waves would wash over the continents and there wouldn't be any men left to curse at all.

Most of these mountain ranges are along coastal borders. The rocky mountains and the pacific range are all close to the Pacific Ocean. If they collapse, the fractures and collapse itself will probably occur beneath the waters surface, causing billions of gallons of water to meet and mix with rock and molten lava. It The coastal areas will actually become a cauldron of rock, lava at extremely high temperatures, and water all mixing together in the profuse shaking. If you have ever had the pleasure of being around a deep frier at 450° F when someone intentionally drops a couple drops of water into it, you know the explosive power of water, even with only a couple drops. A few drops almost becomes like a July 4th Firework going off, and any more than that, you don't want to be around.