Hawaii’s Geology: Ridin’ the Hot Spot!

Boiling hot lava bursts through the crust of the earth and begins a new world, ecosystem, and provides a place for a new culture and lifestyle to form. Welcome to the formation of the Hawaiian Islands. I say that in present tense because it’s still going on 80 million years after it started. Now that sounds like a long time for 8 islands right? Well, that’s because there are technically 91 Hawaiian Islands and even that number is highly disputed among scientists. So to avoid confusion and arguments I’ll let you take a look at the Mejii seamount facts for yourself and form your own opinion.

However, this blog will be talking about the geology of the Hawaiian Islands. But to keep it under twenty pages I’m just going to focus on set of Hawaiian Islands that you’re most likely familiar with: Hawaii/“Big Island,” Kahoolawe, Maui, Molokai, Lanai, Oahu, Kauai, and Niihau. Now I’m likely going to destroy something that you’re probably sure of right away. Each of the islands does not have its own active volcano. Really, there is only one volcanic hot spot under the crust of the earth that made all the islands – one at a time. This is why on tours in Kauai when people asked me where the volcano on the island was I would respond, “Well you missed it by about 5 million years.” Ok, so relax – I know I’m probably destroying everything you think you know about Hawaii. I’m sorry for that but it’s better than you saying something ridiculous if you go to visit! I truly faced questions like this on a daily basis. As a guide I would get questions like “Can I tip you in U.S. money or do you only take Hawaiian?” I also heard “What time do they turn the waterfall on?” and “What elevation are we at?” – as we were kayaking in the ocean. I wish I was making this up, people!
However, let’s get back to the blog at hand. I have to educate you on the formation of the islands before I can “dive into” why Kauai is the best of them all. It’s mostly Kauai’s amazing landscape that makes it the best (this will be the topic of the next blog). To explain how the eight islands are formed, first remember that the world is always moving. Including the continents, the Earth’s top layer is just a bunch of tectonic plates. Movement of these tectonic plates is what causes earthquakes, tsunamis – and volcanoes. Throughout the blog I will refer to the tectonic plates as the “crust” of the Earth. So the crust of the Earth is always moving. The volcanic hot spot is under the crust so therefore it never moves – but remember the crust is always moving…slowly, of course! Millions of years ago the volcanic hot spot went active. While active it pushed hot lava through the crust and over the course of thousands and hundreds of thousands of years of being active, it created an island. After being active for a large period of time it then went dormant – leaving the island to weather and erode on the crust of the Earth. Remember though, just because the volcanic hot spot is dormant does not mean the crust stopped moving. While the hot spot was dormant the crust just kept on moving – taking the new island with it. Remember the hot spot is underneath, so it never moves – but the crust does. When the hot spot next went active it was now under a different part of the crust. So it began forming a new island. After being active for a while it created island number 2. Then it went dormant – and the crust kept moving. See a pattern? By the time it became active again, the island was no longer above the hot spot. So it started making island number 3 – and so on and so forth. This is how the Hawaiian Islands were formed. Now, after being a guide, I know that many people have this view that every island has a volcano spewing hot lava everywhere, all the time – but this is extremely inaccurate. So don’t go to Kahoolawe, Maui, Molokai, Lanai, Oahu, Kauai, and Niihau expecting to see lava or you’re headed for bitter disappointed. If you do want to see the active volcano, you have to go to Hawaii (the Big Island), since that is the part of the crust that the hot spot is currently underneath – it’s so cool (though really, really hot!).

So now you can deduce a couple of things. One – the Big Island is still growing, at roughly 40 acres a year, in fact, – and eating houses and roads up in the process. Two – the farther west the island the older it is (see the map below). This plays an important factor in what’s actually on the island. For example, think about beaches. There are not many beaches on the Big Island that have nice sand. Why? Because the Big Island is so young! It takes a long, long time for the ocean to break basaltic lava rock into nice, loose sand. So this is the beginning of the answer to “Why, in my opinion, is Kauai the best island?” It’s just had the long time to develop. Beautiful landscapes usually take time. So before you just jump on a plane and hop to an island, do your research on all of them and make sure you really know what you’re getting yourself into before you go. Otherwise, you could find yourself on a bunch of black, rough rock where you thought a sandy beach would be!

Traveler’s note- Basic travel research is important. The fact is that gone are the days where you have an excuse for complete ignorance about where you’re going. With the age of technology, you have no excuse. I’m not saying you need to be an expert on every place you travel otherwise there would be no point in going there. However, you should know things like the language spoken, what side of the road they drive on, the currency used, and maybe a few local customs to make sure you don’t offend anyone. However, the best thing to do is before you ask certain things just have a “quick think.” I am referring to questions like, “What time do they turn the waterfall on?” – or doing things like trying to put your baby on a seal on a New Zealand beach for a photo. Once again, I wish I was making these things up! I’m really not just saying this to complain about tourists because while down here in New Zealand, I am one. I am saying this for your safety and, in some cases, the safety of your child if there are seals or other wild animals involved. The fact is also that people overhearing you say things like this label you as someone who they can most likely mess with or take advantage of. Now in most places this is fine but in others, there is always that opportunist thief. This is a sad truth of traveling. Besides that, you make yourself a target for legal thieves – most call them “salesmen.” These people make commission on selling you things you probably don’t need. Just remember you can always just say “No” or walk away. Or better yet, never make yourself a target by just doing a little research on where you’re going and thinking before you speak. This also gives you the start to your game plan on what the unique place has to offer – so that you can see it to the fullest and hopefully travel as stress-free as possible.