Dave took us on another excursion today. The park is about 30 miles north of Hilo. It was a rainy day so the view of Kilauea Crater wasn’t as clear as it is on a sunny day. It was dramatic nevertheless. In the background you can see big steam which comes from Halema’uma’u Crater.
Down a steep trail,
through lush rainforest,
to Thurston Lava Tube.
A natural "pipe" through which lava can flow.
This picture is especially posted for B-in-L Tom the Geologist to analyze.
Steam Vent. As rain water seeps into the ground, it is heated and rised up through the cracks as water vapor. 4 feet down, the temperature is 160°, at the surface it’s 120°.
Kilauea Iki Crater. Hard to see but there is a hiking trail down there and, in the center of the picture, a healthy steam vent.
Another view of Halema’uma’u Crater.
On the way back to Hilo we stopped for lunch at Hilo Coffee Mill. After lunch, Dave spent some time feeding the free range chickens and talking to them.
Meanwhile Dick munched on some banana bread while one particular chicken walked all around him, craning her neck upwards as if to say, “Please, mister, just a crumb or two.” I’m afraid she was disappointed.
Again, Dave, thank you for the excellent tour. You are also being thanked by some of my blog followers for taking us to places that can't be reached by bicycle.
It is more difficult without reference for three dimensions but here is my best shot on your picture. After lava flows out of a tube the walls get cooler. If the lava level then rises again, but not all the way to the top, a layer of new lava will form against the cool edge leaving the tube a little narrower below the maximum height the lava reached.
ReplyDeleteThe vertical crack I presume is just a shrinkage crack. the light color stuff is perplexing because I wouldn't think the tube was old enough for deposits to form from water seeping through, mostly because I would assume the water has little mineralization.
The other perplexing thing, and what makes me think my analysis of the picture is wrong, is that I expected the inside of a lava tube to be rougher. I have never been in one but hope to remedy that when Kev and I go up to Lava Beds National Monument in August.
Tom
Tom, what a great analysis. I'm so glad you can do this on the blog. Perfect! Thanks. Hey, why you ALL come to Hawaii to see the lava?
ReplyDelete