Jeju Islands Gorgeous Geology

 

In a lot of ways Jeju Island is Korea's answer to Hawaii. Both are getaway islands where you can visit someplace exotic without leaving your home country. Both are also massive shield volcanoes looming out of the sea.  In fact, geologically Jeju shares many traits with the Big Island of Hawaii. The Big Island is still active, erupting even as I write this.  Halle-San, the volcano that makes up the bulk of Jeju Island, is sleeping for now.

It last erupted about a thousand years ago, which is only an eyeblink in geological terms. During one of those past eruptions in carved out a few fantastic lava tubes. Lava tubes are formed when the top of a lava flow cools and hardens, insulating the center of the flow. This allows the molten rock to travel further down the flanks of the volcano, and leaves behind some pretty interesting caves. Jeju has two lava tubes of note, one the longest known specimen. The other is one of very few lava tubes to feature stalactites and stalagmites.

 

Stalactites and stalagmites are formed in limestone caves, but the black basalt of Jeju (or Hawaii) holds none of the minerals required for them to form. Except one of the lava tubes spent some time under the sea, and a layer of dead shellfish formed over the lava. After it surfaced, rainwater filtered through the shells and into the cave, bringing with it the lime needed to make the stalactites formations.  

 

For lunch we went for a local specialty, pan grilled black pork. It was heaven. You layer tender strips of pork, some kimchee, some garlic and some hot sauce on a lettuce leaf and make your own Korean fajita burrito. Everything but the pork has free refills, which encourages eating a lot of veggies. I can really get behind vegetables that have been dosed with plenty of garlic and chili pepper. 

On the other side of the island looms Sunrise Peak, a tuff cone built from the explosive meeting of lava and seawater. It was formed about 5,000 years ago, and is one of the most famous and beautiful spots on the island.

The hike up was short but steep, and the late summer heat left us all soaked in sweat. But as always, the view was worth it. It was very, very worth it.