The Blue Dragon Flow erupted from a fissure at the base of Big Craters and the Spatter Cones. The Blue Dragon Flow is one of the youngest flows in the park. Lava tubes are like a giant underground plumbing system for an eruption. They move the lava away from the vent and out onto the plain. Later eruptions can also flow into existing lava tubes if they are still open.
Many different events can cause a lava tube to collapse.
Lava tubes often collapse during the final stages of an eruption as the lava begins to drain from the tube. If the lava drains from the tube while the roof is still soft and plastic, the roof may simply sink as it loses its support from the lava beneath. Another cause of collapse in lava tubes is the shrinking and cracking that occurs as lava cools. This cooling process can shatter the roof of a tube. Over long periods of time, the forces of erosion can also cause lava tubes to collapse.