Happy Thought for 7 August 2026

 Have a Happy Thought:

I’m just going to spew some volcano facts at you today (like a volcano spews lava, get it?).

There are around 1,350 active volcanoes on the Earth.

4 of those active volcanoes are in Antarctica (there are another 15 on the continent, but they’re not considered active)

There might be over a hundred more volcanoes (active or not) under the ice sheets in Antarctica.

When a volcano erupts under a literal kilometer of ice, it actually doesn’t really melt a lot of the ice. It might melt a little bit of the bottom of a glacier, which might speed up a glacier moving (think of a frozen ice cube on a dry table. Now think of putting an ice cube on a patch of water on a table on a slight slope. Oops! That ice cube is off the side of the table now.)

If it does melt a significant amount of water, a sub-glacial volcano can cause a jökulhlaup – basically a massive and sudden flood coming out of the bottom of a glacier.

Image: Cartoons illustrating the two generic types of glaciovolcanic sequences that are found in the Antarctic Peninsula. The sequences are very different and were created during eruptions under different ice thicknesses. A. Lava-fed delta sequence. B. Sheet-like sequence. Source: Subglacial Volcanoes

 

What about when volcanoes erupt on the surface and lava flows out onto an ice sheet? Again, that ice pretty much wins out – not much melts. Basically, the lava just cools really quickly, so you end up with a solidified lava flow on top of a glacier!

Even weirder, the lava can only travel so far before cooling enough to solidify. And this creates a solid wall that traps the rest of the lava behind it. This creates a lava dam, which thousands of years later we can go visit.

Image: The Barrier, a typical ice-marginal lava flow in the Garibaldi Volcanic Belt of southwestern British Columbia, Canada. By JohnHarvey - http://en.wikipedia.org/wiki/File:RockSlide_1200W.jpg, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=25019688

 

The Earth isn’t the only place we’ve found volcanoes. We know there are active volcanoes on Io (a moon of Jupiter), Triton (a moon of Neptune), and Enceladus (a moon of Saturn).

Image: Volcanoes on Io: Io, a moon of Jupiter, is the most volcanically active body in our solar system. It has over 100 active volcanic centers, many of which have multiple active vents. Eruptions recurrently resurface large parts of the moon. NASA image.

 

Io is basically being stretched and compressed by Jupiter’s gravity, and this heats up its insides and also breaks the crust… so volcanoes happen. Triton and Enceladus are also being kneaded by gravity, but in both of these moons it’s surface ice that is acting as a volcano: cryovolcanoes.

 

Meanwhile, the largest volcano, active or extinct, that we know of is on Mars – Olympus Mons.

Horizontal comparison of Olympus Mons with France. By © Sémhur / Wikimedia Commons, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=6374855

Image: comparison of Olympus Mons to Mauna Kea and Mt Everest. Solved Comparison of Olympus Mons to Mauna Kea (Hawaiian | Chegg.com

 

 

 

Thanks to the volcanologists in Antarctica and around the globe for letting us know about this really cool feature of (some) planets (and moons!) https://www.rnz.co.nz/national/programmes/saturday/audio/2019044849/antarctica-s-volcanic-landscape