There’s plenty to say on the matter of bad reporting and misinformation when it comes to volcanic eruptions. No, a supervolcano isn’t what you think it is. No, earthquakes on a volcano aren’t unusual and are often not a sign of an impending eruption. No, just because a powerful earthquake happened around the same time as a volcanic eruption it doesn’t mean the two are connected.
One particular thread is unnervingly ubiquitous. Whenever a sizeable, spectacular or potentially life-threatening volcano erupts somewhere in the world, some rather pesky tabloids tend to link this it to other ongoing or up-and-coming eruptions elsewhere.
Here’s a fun fact for you all: there are at least 20 volcanoes actively erupting on Earth at any given moment. Right now, fiery mountains all over the world are flinging ash and lava onto the surface. Guess what? They’re not connected.
Earth is a geologically active world because it contains two sources of internal heat: decaying radioactive elements, and the primordial embers retained from the planet’s frankly violent birth 4.5 billion years ago. This thermal energy is gradually escaping from the depths of the world and into space, which is why we get plate tectonics and everything that’s linked to, from mountain building and ocean basin formation to massive earthquakes and volcanic eruptions.
Eruptions are a pretty neat way for the planet to cool down, which is why they are always taking place. That’s really all there is to it – it’s just our pale, blue dot attempting to chill. Don’t take my word for it, though: courtesy of the United States Geological Survey (USGS) and the Smithsonian Institution’s Global Volcanism Program, you can find out for yourself which volcanoes are erupting right this very moment by clicking here to view a constantly updated list.
At the time of writing, 40 volcanoes are erupting. These include the little baby volcano within Indonesia’s Krakatau, the otherworldly Tanzanian volcano Ol Doinyo Lengai, and Antarctica’s Saunders volcano. This is normal, and fine.
Each volcano is idiosyncratic. They have their own eruption styles and eruption frequencies. Some, like Sicily’s Stromboli, produces multiple lava fountains every single day. Others, like Guatemala’s Volcan de Fuego, can be quiet for some time before a major explosive eruption suddenly takes place.
The volcanoes on this list are classified as having an ongoing or continuing eruption. This doesn’t necessarily mean that, right now, lava or ash is emerging from its vents or fissures. As the recent Kilauea eruption highlighted, it’s not easy to tell when an eruption has paused or stopped. Sometimes a volcano can calm down a little and go quiet before it engages in a quick follow up paroxysm; other times, an eruption can rapidly wind down and the volcano goes properly quiet.
In order to handle such uncertainty, the update classifies a volcano as erupting if “there have been at least some intermittent eruptive events at that volcano without a break of at least 3 months since it started.”
This site, which also comes with more detailed weekly updates on the volcano, also lets you know how explosive each ongoing eruption is. This is measured by the Volcanic Explosivity Index (VEI), a scale from 0-8 that’s largely based on how much new volcanic material is ejected during the eruption. The height of the ash column produced by the eruption is also taken into consideration.
In general, VEI value roughly correlates with an eruption’s frequency. VEI 0 eruptions take place where trapped gas and magma can easily make it to the surface, and the magma itself isn’t that viscous and gloopy. Think common Hawaiian or Icelandic lava flows – these eruption types are always happening somewhere in the world.
On the other end of the scale you have VEI 8 eruptions. These produce 1,000 cubic kilometers (240 cubic miles) of fresh volcanic material, and are often associated with climatic changes and widespread environmental devastation. It takes time to build up an eruption of this magnitude, though, which is why they only take place on timescales of tens of thousands of years.
Forecasting when a colossal eruption like this will take place is supremely difficult; they erupt so infrequently that any pattern, if it exists, isn’t discernable. Fortunately, any eruption this size will give clear warning signs before it does, so it wouldn’t simply spring up out of nowhere.
It’s worth remembering that explosivity isn’t a proxy to how dangerous an eruption may be. Remember, it’s people and infrastructure that make eruptions hazardous by simply being in their way. An eruption could be incredibly explosive but it might happen in a location so remote that it doesn’t affect anyone. Conversely, a non-explosive eruption involving just lava flows can prove devastating to the local population if it floods into their towns.
These points are worth keeping in mind as you peruse the database. Fortunately, even without them, the most important aspects of the site (to my mind, at least) come across quite clearly. It doesn’t just serve as a reminder that Earth is a world unrivalled in the Solar System for its volcanological diversity; it also underscores that volcanic eruptions aren’t unusual or, for the most part, anything to be feared.
They certainly aren’t harbingers of the end of days. A fireworks display in Russia doesn’t have any impact on a lava lake overflowing in eastern Africa. No matter what you may read elsewhere, volcanoes aren’t all linked up in some unholy, death-bringing alliance.
Volcanoes extremely close together may perhaps share a solitary magmatic source, but this hasn’t been convincingly demonstrated. Just take the recent eruption of Hawaii’s Kilauea: this volcano spent several months ejecting various types of lava all over the shop, but this had no effect whatsoever on Mauna Loa, the gigantic shield volcano it’s close neighbors with.
As noted by the USGS, both volcanoes have independent shallow magma reservoirs. In fact, even though it may be perhaps possible for two very closely spaced volcanoes to affect each other and trigger near-simultaneous eruptions, there’s no solid evidence as of yet that this is true.
Mauna Loa and Kilauea are pretty much butting up against each other. Most volcanoes, even if they’re part of a chain, are spaced further apart. They operate according to their own individual machinations, and they are not connected in any way. Whether they are in the same country or they simply share the same tectonic plate boundary, they will act alone.
Any eruptions happening at the same time are nothing more than coincidences, whether we’re talking about a pair of volcanoes or – as it the case right now – 40 of them.