Tube - John Seach
Lava tubes are natural conduits through
which lava travels beneath the surface of a lava flow.
Tubes form by the crusting over of
lava channels and pahoehoe flows.
When the supply of lava stops at
the end of an eruption or lava is diverted elsewhere,
lava in the tube system drains downslope
and leaves partially empty conduits beneath the ground.
Lava tubes are very common formations
of Lava Tubes
Thurston (Nahuku) lava tube near
summit caldera of Kilauea Volcano in Hawai`i Volcanoes National Park
Undara Lava Tubes, Queensland, Australia.
These are the largest in the world.
Copyright John Seach