<P> The volcano usually generates Plinian eruptions , which produce swift - moving currents of hot gas and rock called pyroclastic flows . These eruptions often cause massive lahars ( mud and debris flows ) , which pose a threat to human life and the environment . The impact of such an eruption is increased as the hot gas and lava melt the mountain 's snowcap , adding large quantities of water to the flow . On November 13 , 1985 , a small eruption produced an enormous lahar that buried and destroyed the town of Armero in Tolima , causing an estimated 25,000 deaths . This event later became known as the Armero tragedy -- the deadliest lahar in recorded history . Similar but less deadly incidents occurred in 1595 and 1845 , consisting of a small explosive eruption followed by a large lahar . </P>
<P> The volcano usually generates Plinian eruptions , which produce swift - moving currents of hot gas and rock called pyroclastic flows . These eruptions often cause massive lahars ( mud and debris flows ) , which pose a threat to human life and the environment . The impact of such an eruption is increased as the hot gas and lava melt the mountain 's snowcap , adding large quantities of water to the flow . On November 13 , 1985 , a small eruption produced an enormous lahar that buried and destroyed the town of Armero in Tolima , causing an estimated 25,000 deaths . This event later became known as the Armero tragedy -- the deadliest lahar in recorded history . Similar but less deadly incidents occurred in 1595 and 1845 , consisting of a small explosive eruption followed by a large lahar . </P>
what type of eruption does nevado del ruiz produce
what type of eruption does nevado del ruiz produce
Plinian eruptions
Plinian eruptions