Original: The Armero tragedy , as the event came to be known , was the second-deadliest volcanic disaster in the 20th century , being surpassed only by the 1902 eruption of Mount Pelée , and is the fourth-deadliest volcanic eruption in recorded history .
Simplified: This was the second deadliest volcanic disaster in the 20th century , ousted only by the 1902 eruption of Mount Pelee , and the fourth deadliest eruption in recorded history .