Here's why:

* Fissure volcanoes erupt from long, narrow cracks in the Earth's crust. These cracks, called fissures, can be miles long.

* Laki's eruption in 1783 was a massive event that poured lava from a fissure around 25 kilometers long.

It's important to note that Laki is part of a larger volcanic system called the Grímsvötn volcanic system, which includes a caldera and other volcanic features. However, the 1783 eruption is specifically associated with the Laki fissure.