An active volcano may erupt at any time.

活火山会随时喷发。

《牛津词典》

Doing that in many of the forests of the western US is like building homes on the side of an active volcano.

在美国西部的许多森林里那样做就像在活火山边上建房子一样。

youdao

Vesuvius is an active volcano.

维苏威山是一座活火山。

youdao

Visitors can see how an active volcano adds mass to the island.

VOA: special.2010.09.08

The island has an active volcano, Mount Pelee, which erupted in 1902, razing the town of Saint-Pierre and killing its 30, 000 residents.

BBC: Martinique profile

Mount Rainier is also an active volcano - although there has been no activity since the 1850s and geologists say there is no imminent threat of eruption.

BBC: Seattle side trips in every direction

We pass a white wall of mountains off to the left and, on the right, an active volcano with steam curling out of the vent.

NPR: Penguins Helped and Hurt by Changing Climate