why do some volcanic eruptions consist mostly of lava flows
Lava Flows. The major eruptive product of Hawaiian volcanoes is lava. Lava flows can form during fountaining eruptions or they can well out of the ground with little or no pyroclastic activity. There are two major types of basaltic lava flow, ' a'a and pahoehoe.ava flows can form during fountaining eruptions or they can well out of the ground with little or no pyroclastic activity.
When magma reaches the surface of the earth, it is called lava. Since it its a liquid, it flows downhill in response to gravity as a lava flows. Different magma types behave differently as lava flows, depending on their temperature, viscosity, and gas content. Lava flows are produced on the surface, and these run like liquids down slope, along the lowest areas they can find. 2  If the magma emerges along a fracture, it results in a fissure eruption, often called a curtain of fire. 3  Lava flows produced by eruptions under water are called pillow lavas.