Zechariah 14:4-5

4And his feet shall stand in that day upon the mount of Olives, which is before Jerusalem on the east, and the mount of Olives shall cleave in the midst of it toward the east and toward the west, and there shall be a very great valley; and half of the mountain shall remove toward the north, and half of it toward the south.

5And ye shall flee to the valley of the mountains; for the valley of the mountains shall reach to Azal: yea, ye shall flee, as ye fled from before the earthquake in the days of Uzziah king of Judah: and the LORD my God shall come, and all the saints with thee.12