A long crack from which lava flows through is called a fissure.

Here's why:

* Fissure: A fissure is a linear crack or fracture in the Earth's crust. These cracks can range in size from a few inches to several miles long.

* Lava Flow: When magma (molten rock beneath the Earth's surface) rises to the surface and erupts through a fissure, it creates a lava flow.

Important Note: Fissure eruptions are often associated with vast outpourings of lava, covering large areas. They are distinct from volcanic eruptions that occur from a central vent, like a cone-shaped volcano.