Which of the following volcanic hazards occurred from Mount Nyiragongo [nee-ir-uh-GON-goh] in 1977, killing 70 people in nearby villages?

W) Eruption of a pyroclastic flow [py-ruh-KLAS-tik]

X) Draining of a lava lake

Y) Eruption of a noxious gas cloud

Z) Creation of a large lahar
X) DRAINING OF A LAVA LAKE