Nahuku (Thurston Lava Tube)
Nahuku, also known as the Thurston Lava Tube is a 500-year old lava cave located within Hawaii Volcanoes National Park. Lava caves like this are formed when a river of lava gradually builds solid walls and a ceiling. When the lava flow stops and the last of it passes downhill, a cave is formed. These caves can be a few feet high and only yards long, or they can stretch for miles with high ceilings. There are several lava tubes you can visit around the island but Nahuku is the most easily accessible and is a fantastic example of a massive lava cave.
Lit by electric lights, with a flat rock floor and a ceiling high enough in the center to keep you from scraping your head, this is a great introduction to lava tube geology. The solidified drips and waves of once-liquid lava rock clearly show the molten forces that created this cave. Your flashlight reveals beautiful shapes and colors of minerals leeching from the rock. After strolling the short, lighted section of Nahuku, there’s another segment past the steps leading back up the trail that’s completely dark with an uneven floor, so don’t venture there unless you are sure-footed and have a strong flashlight.