Guatemala, a destination you´re gonna lava. I mean, love.
I love Volcanoes. I think volcanoes are pretty neat. So neat that I decided to get my undergrad degree in geology. Every rock has a story to tell. However, the problem with geology is how slow and long the process takes to see any sort of change. We are talking in terms of millions of years. I don't have that much time. You probably don't either. What if I told you that you could see geology happen instantly in front of you, and feel the absolute raw destructive power that only planets can produce? Or maybe you just want to see rocks being born in the sky. The only place that can happen is at volcanoes. I have never seen a volcano erupt but I knew I had too. It is kind of hard to plan to see a volcano erupt on your schedule. Sometimes they are in remote and/or dangerous places or just 
On any given day about 20 volcanoes erupt. Guatemala has two volcanoes that erupt on a daily basis. Even better was that you could camp out and watch one erupt all night. I told myself that I am going to Guatemala just to see Fuego erupt. That was probably one of the best decisions I ever made. Fuego and Guatemala were incredible. So incredible that I went back 3 more times that year. I was not content with just watching OG fireworks. I needed to understand the geology of Guatemala and its volcanoes. It was way more complex and unique than imagined. We are talking love triangles and a country literally being torn in half.
Guatemala has 37 recognized volcanoes. 23 volcanoes have erupted in the past 10,000 years and are considered active. In 2021, 3 volcanoes were all erupting at the same time. That is crazy when you realize how relatively small Guatemala is. You will need 3.5 Guatemala's to make 1 Texas. Why are there so many volcanoes in Guatemala? Well just like the correct answer to every Geology 101 class test question, plate tectonics. Plate tectonics is the theory that the earth’s crust is not solid but broken into pieces, called plates. Think of pieces in a puzzle. The heat from the mantle causes the plates to move and crash into each other. Where these plates meet is called a plate boundary or fault. That sounds nice and all but if it is a convergent plate boundary then it is actually 2 plates fighting to the death. The losing plate gets forced underneath the winning plate then gets melted in the earth's mantle. These battles are so violent that when the plates move the earth literally quakes causing earthquakes. As the losing plate melts trapped gas is released and like an upset stomach that gas has to go somewhere. The gas and magma are forced up through the crust. When the molten material reaches the earth's surface it erupts. And boom goes the dynamite and you got yourself a volcano. A less common and more friendly plate boundary is the transform boundary. That is where two plates do a little bump and grind past each other and make earthquakes. The San Andreas Fault is a transform boundary. The final boundary type is the divergent boundary. That's where two plates go their separate ways in an amicable breakup. The most famous plate boundary makes a ring roughly around the Pacific Ocean. 90% of the world's earthquakes and 75% of all volcanoes are found in this boundary, so scientists decided to give it an awesome name. The Ring of Fire. As you might have already guessed it, Guatemala is on the Ring of Fire.
Most of the volcanism on the Ring of Fire is attributed to the Pacific Plate being subducted at the boundary. So, someone might assume that the volcanism in Guatemala is from the Pacific Plate subducting off the west coast underneath Guatemala. Yes and no, there is a plate subducting along the west coast but it is the Cocos Plate and not the Pacific Plate. If it was just two plates meeting then that would be the end of the story except there is one more plate and it is literally tearing Guatemala in half. Guatemala is in a plate tectonic love triangle or known geologically as a triple junction. Three plates meeting at one point is very rare. There are only 10 possible triple junctions on earth. Guatemala itself is located on two different plates. The northern half of Guatemala sits on
the North American Plate and is moving to the west. The southern half sits on the Caribbean Plate and is moving to the east. That creates a transform fault that horizontally splits Guatemala in two. While the transform fault does not create volcanoes it is important to know in order to understand the geology of Guatemala.
Then there is the other side of the tectonic love triangle. The Cocos and Caribbean subduction zone. The Cocos Plate is subducting underneath the Caribbean Plate. The melting creates a line of volcanoes starting in Guatemala extending down to Costa Rica. Some of Guatemala's notable hits include Pacaya, Santa Maria, and the super volcano Atitlán. But the whole reason I went to Guatemala was because of Fuego. Since 2002, The stratovolcano has erupted on average every 15 to 20 minutes. Fuego has Magmatic type eruptions simply meaning basaltic lava and pyroclastic material is being ejected during eruptions. Magmatic eruptions are further broken down into eruption style. Most of Fuego's eruptions are minor and classified as Strombolian style eruptions. The Volcanic explosivity index (VEI) is the scale from VEI-0 to VEI-8 used to determine how explosive an eruption was.
VEI-0 is a Hawaiian type eruption and VEI-8 is a supervolcano. Fuego's normal eruptions are VEI-1 or VEI-2. It is extremely rare for Fuego's eruptions to be greater than a VEI-2. Fuego does have some notable eruptions. The 2018 eruption was a VEI-3 the largest recorded eruption was VEI-4 in 1974. During the day Fuego's eruptions vary in color from light gray to black. Light gray eruptions are made up of mostly steam and other gasses and are pretty boring. The darker eruptions consist of pyroclastic rocks the size of fine ash up to the huge volcanic bombs with maybe a little dribble of lava down the side. When the sun goes down the eruptions become truly awe inspiring. If you're a fan of campfires then buddy you are in for a treat. What looks like smoke during the day is thousands of pyroclastic rocks and lava glowing bright orange at night. I really can't describe the feeling of seeing the sky light up with falling rocks.
I can talk about Fuego and plate tectonics for hours but then this post would be more of just me rambling on. I barely mentioned Fuego's older twin, Acatenango. But I did write a blog post about it here. Did you know that the Fuego/Acatenango complex isn't made of just two volcanoes but five volcanoes? I'll stop. I only just started to scratch the surface. That's why I keep going back to Fuego and Guatemala. I love it there. Antigua is a town unlike anywhere else that has an aesthetic that can only come from centuries of earthquakes and Spanish colonization. If learning about something to understand it beforehand makes an experience more enjoyable then maybe this post helped. If you just wanted to see a volcano erupt, I won't blame you because you will see that volcanoes are pretty neat.
Corey Wheeler
Geologist
Texas A&M University - Corpus Christi
