Thursday, August 18, 2016
The Dumbest Thing We Did in Korea, and the Smartest
It was, I don't know, 1800 yards high. That doesn't sound like a lot, I guess, but it means a whole lot of stairs. Did I mention it was about 100 degrees hot out there in the sun?
This is inside the caldera all green and pretty.
Back to the steep sided seafront.
So even two, icy drinks at Starbucks (black tea and green grapes, extraordinarily delicious and not available here in the states) after the climb down did not restore my usual core body temperature and it was pretty miserable even in the air conditioned car. But then we made a good choice. Let's go see the huge complex of lava tubes in the interior of the island, we said. (Oh, we were on Jeju, a teardrop shaped semi-tropic island in the Yellow Sea off the southwest corner of Korea).
Lava tubes, as the name might suggest, are tubes of solid stone through which lava has flowed (and cooled and solidified on the outside creating the tube in the first place) so they are long, slightly meandering caves with black rock flowstone insides, very like the walls inside of the alien space ships in Alien and Prometheus.
Here's the entrance from the surface.
Every step down into the tube cooled down about two degrees. So we went from 100 to about 45 American degrees. It was a very heaven below ground.
Sometimes the ceiling collapses creating a high dome like ceiling. The ceiling shown here is of other rock than solidified lava and had that not been there the ceiling collapse would have created a different entrance to the tube.
Details of the walls of the tube.
I'm not certain, because the floor of the tube is rough and could be original cooled last run of lava, but I tend to think it's man-made disguised to look like it's cooled lava. It certainly was at a very useful height for human visitors. Last two.
Sometimes, cooled lava rocks fall into the stream of lava but are not re-melted and create rafts. This one is remarkable for its similarity to the whole island of Jeju. You can see cooled lava adding to the edge of the raft on the left.
It's very common for tubes to be on top of each other and sometimes lava leaks from above, like here.
This tube was the only one we went in but there are about a dozen there, some of which they let you enter, with very different features (like ground water stalagmites and stalactites, etc.).
Apparently the best lava tubes in continental America are the Ape Cave (or Caves) on the south slope of Mt. St. Helens north east of Portland, OR in Washington state. I'm so interested in these tubes because of some knowledge of them from the "color" Mars book series by Kim Stanley Robinson. Because of the difference in gravity, the tubes would be even larger on Mars. Good place for the doomed volunteers to spend their last days a few decades from now. You could seal one end and pump in an atmosphere and heat. Perhaps even put in some skylight windows and create a greenhouse. Just an idea (from author Robinson).
Labels: Korean Calderas and Lava Tubes