In Zechariah 14:4, which mountain will split in two when His feet stand on it?

Answer: The Mount of Olives

His feet will stand on the Mount of Olives, east of Jerusalem, and it will be split in two from east to west, forming a great valley.

“On that day His feet will stand on the Mount of Olives, east of Jerusalem, and the Mount of Olives will be split in two from east to west, forming a great valley, with half the mountain moving to the north and half to the south.”— Zechariah 14:4 (BSB)