eruption, irruption

Eruption or eruption means the explosion of ash and lava that comes from a volcano--
Everyone on the west coast still remembers the eruption of Mount Saint Helens.
The most famous volcanic eruption was Vesuvius, which left behind Pompeii and Herculaneum.
Eruption may be used figuratively, as a violent outburst--
His patience finally ended in an eruption of shouting and emotion.

Irruption or irruption ( rhymes with eruption ) means a sudden or violent invasion or breaking in--
The meeting ended with an irruption by the protesters from outside the building.
Irruption may also mean a sudden burst of noise or activity by a crowd of people--
The peaceful crowd gave way to a violent irruption.

Now that you know that, you can say--
"News of the volcanic eruption was cut off by the irruption of a group trying to get to the news cameras."

Note--either "eruption" or "irruption "  might mean a violent outburst from a crowd.
Only "eruption" means an explosion by a volcano, spewing ash or lava.
Only "irruption" means a noisy invasion or interruption.