One the tube is formed, lava from later eruptions may find its way through the tube. The line on the wall of the tube shows the height of a later flow.
Kilauea's lava erupted from a vent in May, 2016 and slowly made its way to the ocean, 16 miles away. The lava began to enter the ocean in late July. Lava tubes have formed in some areas and molten lava can be seen through "skylights", as seen here.
|Photo courtesy of atlantic.com "The Atlantic Photo" site|
|Another photo courtesy of atlantic.com "The Atlantic Photo" site|