The question is, would THOSE READERS have understood that to happen literally? The answer is no. Why? Because it was figurative language used over and over again and not ever intended to be literal.
In Micah 1:3 we are told that God “is COMING FORTH FROM HIS PLACE” to “COME DOWN and TREAD on the HIGH PLACES (mountains) of the earth.” Do you believe Jesus literally physically did this treading with his feet? How is this descriptive language different from the Lord standing on the Mount of Olives with the result that it will split?
Micah goes on to say “the MOUNTAINS will MELT UNDER HIM, and the valleys WILL BE SPLIT, like wax before the fire, like water poured down a steep place” (1:4). Did they literally split in this case? Did they literally melt? No they were apocalyptic language to describe the activity of God, usually in judgment or deliverance.
For instance, “And the LORD CAME DOWN to see the city and the tower which the sons of men had built. . . . Come, let Us GO DOWN and there confuse their language, that they may not understand one another’s speech” (Gen. 11:5, 7).
“So I HAVE COME DOWN TO DELIVER THEM from the power of the Egyptians, and to bring them up from that land to a good and spacious land, to a land flowing with milk and honey. . . (Ex. 3:8).
“Then Thou didst COME DOWN on Mount Sinai, and didst speak with them from heaven. . . (Neh. 9:13a).
The splitting of the mountain is reminiscent of the splitting of the Red Sea where the nation was delivered. It is a word picture of deliverance! So too in 70AD there was deliverance for the believing Jews while the apostate Jews were judged and scattered among the nations.
It was Jesus himself who said in Matthew 16:27-28,
"27 For the Son of Man will come in the glory of His Father with His angels, and then He will reward each according to his works. 28 “Assuredly, I say to you, there are some standing here who shall not taste death till they see the Son of Man coming in His kingdom.”
How did the Father come in the past to judge... in the same way that the Son would do as God... using other nations to bring judgment such as he did when Rome came to destroy Jerusalem while some of them were still living. This is how he "came down".