
Observe the image of the individual walking through the lava tube. Why is it hollow there and not solid rock?
◦ When lava cools it contracts, leaving large gaps in the middle.
◦ Lava on the inside of the tube often remains molten while the outside crystallizes. Sometimes that molten lava flows out, leaving an empty interior.
◦ The inside of the lava tube was granite, but granite is not resistant to weathering, so has long since eroded away.
◦ There are no natural openings within a lava flow. This must be a manmade feature.