The opening in the Earth's crust through which volcanic materials pass to the surface is called a vent.

Here's a little more detail:

* Vent: The main opening through which lava, ash, and gases erupt from a volcano.

* Crater: A bowl-shaped depression at the summit of a volcano, often formed by explosions or collapses. It often contains the vent.

* Fissure: A long, narrow crack in the Earth's surface through which volcanic materials can erupt. These are more common in shield volcanoes.

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