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TREX 2018 Day 3: Geology of Kilauea Iki Crater

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TREX 2018 Day 3: Geology of Kilauea Iki Crater

By James Pruegsanusak ’19

This is my first time writing a blog for CEE, so here’s a self-introduction. I’m James Pruegsanusak, a junior majoring in Electrical Engineering and Computer Science. Yes, that’s right – I’m a course 6!

TREX is a great opportunity to travel to this unique, beautiful island while learning a ton about environmental problems, not to mention fleeing away from the January snow in Boston.

A view of the Kilauea Iki Crater from the start of the trail

The downhill trail that led us into the crater.

We could often stop to look down into the crater.

Led by Prof Ben Kocar, we started off the third day by with a hike around – and within – the Kilauea Iki Crater. Since Kilauea is still an active volcano, it is not too surprising that the crater was just formed due to an eruption in 1959. The 4-mile trail began from the top, where we walked through rainforest (literally rain and forest) with dense vegetation, gradually down into the crater. Then we walked across crater for about 2.4 miles, on the ground which has undergone extreme geological processes in the past 60 years ago. Walking into rainforest again, but upward, completed the loop and finished the trail.

From inside the Kilauea Iki Crater, you can see vast, grey ground with very sparse plants, lichens, and blue green algae. However, within this wide area, the geological structures vary from one part to another. The first part was rougher, formed by hot lava “a’a” (it’s too hot you can’t touch it but cry “ah-ah”), while the second half was smoother due to the other type of lava “pahoehoe” which is more viscous. We could see different sizes of rocks and structures such as cracks in various scales. The heterogeneity can also be found within each piece of rock, because different minerals cool at different rates when rock cools down.

The Kilauea Iki Trail within the crater.

Prof Ben Kocar explained the geology of the crater in the middle of the rain.

The minerals found here are mainly composed of calcium and magnesium, but not silicon. Despite being more common in the Earth’s crust, silicon is found less in the magma due to lower density. Therefore, quartz (SiO2) should not be found in the crater. A chemical reaction between sulfuric acid (acid rain) and these minerals explains why there is white salt deposit on the surface of some rocks. The salt is gypsum, or calcium sulfate.

Panoramic view of the crater.

Right next to the Kilauea Iki Trail was the Thurston Lava Tube (Nahuku), which we went to see after finishing the crater trail. A lava tube is formed by a large river of lava flow. The edges cool down, while the hot central currents still move. This can create a lava tube when the center gets drained after the eruption stops. This particular tube is approximately 600 ft long with ceilings between 10 and 30 ft, and was formed about 400 years ago.

Entrance of the lava tube.

Towards the end of the lava tube.

Every year, a group of MIT students and professors travel to the Big Island of Hawaii to gain fieldwork experience through TREX (Traveling Research Environmental EXperiences). The first TREX trip was held in 2000, and since launching has taken students on research activities in domestic and international settings. For more undergraduate opportunities, click here.