Revelation 16:18

there were noises and thunderings and lightnings
Noises is φωναὶ [phōnai] which could also be translated as “voices.” Initially, these sounds of judgment and power were manifested in heaven (Rev. Rev. 4:5+). There, they were a warning of what has now finally come to the earth. See commentary on Revelation 4:5. In the prelude to the seven trumpet judgments, the angel of the altar threw his censer full of fire to the earth with similar results (Rev. Rev. 8:5+). Together with the earthquake and the great hail, these manifestations of judgment point to the ark of the covenant containing the Ten Commandments (the “testimony”) by which the godless behavior of the earth dwellers is rightfully judged. See commentary on Revelation 16:21.

there was a great earthquake
There are numerous earthquakes associated with the time of the end.

1. Jesus taught that earthquakes were an indicator of “the beginning of sorrows” (Mtt. Mat. 24:8).
2. A tremendous earthquake results from the opening of the sixth seal, attended by cosmic signs (Rev. Rev. 6:12+).
3. There was an earthquake after the seventh seal, but before the first trumpet, when the angel of the altar took the censer, filled it with fire, and threw it to the earth (Rev. Rev. 8:7-10+).
4. At the ascension of the two witnesses a great earthquake leveled one tenth of Jerusalem contributing to the conversion of those who remained alive (Rev. Rev. 11:13+).

This earthquake surpasses them all.

Haggai prophesied of a great shaking which would involve all nations prior to their recognition of Christ and the return of the shekinah glory of God to the Millennial Temple:

For thus says the LORD of hosts: ‘Once more (it is a little while) I will shake heaven and earth, the sea and dry land; and I will shake all nations, and they shall come to the Desire of All Nations, and I will fill this temple with glory,’ says the LORD of hosts. (Hag. Hag. 2:6-7)

as had not occurred since men were on the earth
This earthquake is the most powerful earthquake since the sixth day when Adam and Eve were created. Although some tie it to the earthquake which attends Gog’s attack upon Israel, it is not the same earthquake. The attack by Gog upon Israel (Eze. Eze. 38:1, Eze. 39:1) is not part of the Tribulation events associated with the Campaign of Armageddon. Also, that earthquake, although felt all around the world, is localized in its immediate effects to the “land of Israel” (Eze. Eze. 38:19). The mountains that are thrown down, in the context, are the mountains of Israel where Gog will be defeated (Eze. Eze. 39:2). This may be the earthquake which attends the pressure of Messiah’s foot upon the Mount of Olives and results in its being split in two (Zec. Zec. 14:4).