Boom! That was the sound of formation of the universe (about 13,8 billions of years ago) and about 9,26 billion years later, our pretty little planet formed. At first, it was very hot, with many volcanic eruptions and the place literally looked like hell. In time the volcanic eruptions got less frequent and smaller, the atmosphere formed and the Earth’s surface cooled down. This event, together with many other, led to the formation of life and eventually led to great diversity, that we still see today.
How the eruption occurs?
Well, it all starts with the movements of magma deep under the surface of the Earth’s crust (that we divide into 5 layers). The magma that is located deep is hot and is moving toward the surface because the density there is a lot lower. On the other hand, the colder magma is moving back to the center of the Earth, where the density is higher. This process is making the convection currents, that are responsible for movements of molten material and the tectonic plates.
The locations where the volcanoes will form are highly depending on the movements of the tectonic plates. They can occur on locations, where the two tectonic plates come together, drift apart or on so-called hot spots. Those are the spots, where magma is able to come close enough to the surface to penetrate it. This is greatly influenced by the amount of pressure as well as the rock layer structure under the surface.
How do we monitor this?
The answer to this questions is the seismic waves. For a long time we were detecting these waves and putting them on papers and the actual people were reading and evaluating them. These waves were picking up much un-useful information (like waves, normal sliding of continental plates etc.), that were sometimes misinterpreted also by an experienced human eye. There was also almost no chance of predicting the next eruption so that when it actually occurred, many lives were lost and the whole event created an overall chaos. So, since we are always seeking out to better ourselves and to predict everything, we took the step in developing new ideas.
Today these same waves are used to look under the Earth’s skin. By this, I am referring to pointing the waves at the Earth’s crust and collecting the data that gets back (from about max 60km of depth). The waves we send are of different wavelengths, which enables them to travel to different depths. It is also known, that the rays are traveling differently, through different states of matter (gas, liquid, plasma and solid). All of this enables us to get a very good and beautiful 3-D picture. Yes, the technology really is amazing (look at this!), but only until you see the movements of molten rock towards the surface, which then make these pictures just terrifying!
These pictures come to great use since we are able to see the movements soon after they happen. Because of this, we are now capable of making the necessary evacuations of people living in the areas that are potentially in danger from the eruption. Moreover, we are capable of doing this quite sometime before the danger strikes.
And after the eruption?
Being close to the volcanic eruption can be very dangerous, but not only because of the molten rock (at 800° C -1200° C) that can very easily turn you into ash. The danger also comes from the gases and falling ash that is released during the eruption as well as some other hazards.
The principal components of volcanic gases are water vapor (usually up to 60% (or more)), carbon (in forms of CO and CO2), sulfur ( in forms of SO2 or H2S), nitrogen, argon, helium, neon, methane, and hydrogen. There can also be traces of other elements, but this differs between the volcanoes. After the eruption, the gasses (as well as the ashes) are being distributed around the planet with the winds and may cause problems on places that are located far away from the place of the eruption.
Have you noticed, that I mentioned 2 greenhouse gasses (carbon dioxide (CO2) and methane (CH4)? We use to mention them when talking about climate change and burning the fossil fuels. These gases also have their natural sources, which are (besides the volcanic eruption) the geothermal and sedimental eruptions as well as the respiration of soil, animals, and plants.
Since the reasons, why molten rock is preventing the plant’s growth are quite obvious (heat and physical limitations), I would like to say some more words about the role of volcanic ash. How much of the effect it has, has a lot to do with the thickness of the ash blanket. Of course, it is hard to say what exactly is the magical thickness that makes everything die (due to lack of sunlight) since it also depends on the plant species. High concentrations of ash, can also have a great effect on the air quality and might present a health hazard to everything that breathes. The reason behind this is the presence of teeny-tiny glass-like particles, that form during the eruption as well as the increase of dust particles in the air.
With so many problems – why would someone like to live in a place like this?
You might be surprised to see this picture showing how many volcanoes there actually are on Earth. Of course not all of them are active, but still, take a moment to take it all in.
All right, but still, there is a lot of space that you can choose from where there are no volcanoes! I completely agree with you, and there are many stories of places like Pompeii (Italy) where many people died to back you up. Even though we know about these cases, some people still choose to live right under the volcanoes and many of them return right after the danger is over. Okay, but… Why would someone do this? There are actually many reasons for them to do so. The land is very cheap and unimaginably fertile, which makes the food production very easy. The volcanic rock is also a great building material and the steam and water from volcanoes can be used as heat and electricity supply. At this place, many valuable minerals and metals can be found (jobs) and since the volcanoes are pretty fascinating, it makes them a popular travel destination.
With research and technology, we already managed to save many lives and will continue to do so in the future. However, there is still a lot of things we don’t know and could do better. In time we could maybe be capable of looking even more into depth than ”only” 60 km. We could maybe also be able to predict the exact time of an eruption or the location of an earthquake, which would save a lot of lives and prevent some natural catastrophes.
What are your thoughts on this topic? Would you consider living close to the volcano? What kind of research would we need to do more of in your opinion? Please share your thoughts below, I would be very happy to read them!