Guest Videos: The Source of Lava

Magma chambers are hot news this month (sorry, couldn’t resist).

  • Yellowstone reportedly contains more liquid magma than they thought (but still isn’t expected to let loose with it any time soon).
  • A study has found that changes in its internal plumbing are “rejuvenating” Stromboli, in Italy.
  • About ten minutes into its big BOOM! last January, a “magmatic hammer” might have struck the base of erupting Hunga-Tonga Hunga-Ha’apai four times.

    Japan Meteorological Agency/NASA SPoRT via Wikimedia.

And something down there under the surface of Hawaii Island — perhaps stress field changes on their individual storage reservoirs — shut down eruptions at both Kilauea and Mauna Loa.

None of this means that volcanoes are getting unusually active, despite what we sometimes read in the online news.

The whole thread is interesting.

The news coverage just means that scientists are getting better at various chemical and geophysical ways to “see” through the miles of rocky crust that separate us from magma until circumstances are right for it to erupt as lava.

And they’re making some amazing new discoveries that help them to understand how volcanoes work and that also may improve hazard management at active volcanoes.


But what’s a magma chamber?

The short answer: It’s not simply a heat source sitting in the crust, waiting to run a geologic version of our lava lamps when the local lid comes off.

This isn’t exactly wrong, but volcano plumbing is so much more amazing!

We laypeople have that basic “bubbling pot” impression because it’s the easiest way to diagram a volcano’s plumbing when trying to explain eruptions — and also because that’s what we see when it’s possible to visit one:

Why Iceland? By the way, Thrihnukagigur is said to be the only known place on Earth where you can do this, but it isn’t Iceland’s only “basaltic cannibal“.

The long answer is actually a work in progress.

Some of the best minds on this planet have dedicated their whole careers to answering the deceptively simple-sounding question: “What is a magma chamber?”

It gets quite arcane, but I like Huff and Owen’s definition in this list:

Magma chambers are subterranean reservoirs containing molten silicate fluid. Some are staging areas for volcanic eruptions, whereas others have no link to Earth’s surface but instead undergo cooling and solidification to form coarse-grained plutons.

Even better, I like some of the brief, trippy videos and images of hypothesized volcanic plumbing systems that have come out of this ongoing research, for instance:

At Yellowstone (2015):

Associated article.

At Iceland (a 2022 Twitter thread):

And at a Pleistocene/Holocene Mexican volcano

Lucci et al., Figure 12, CC BY-SA 4.0.


But this is not unusual. From the very little bit that I’ve been able to read and understand, more recent research has shown that volcanic plumbing typically is very complicated.

PBS Digital Studios via Giphy.

Well, what else can we expect? Earth is shedding a lot of heat out into space, and that has to work its way up through almost two thousand miles of blanketing mantle rock to the surface somehow.

That heat runs plate tectonics. It makes life possible on the planet’s surface.

And every volcano that has ever existed is the unique end product of the heat transfer process, one that, although localized, took a sizable chunk of geologic time to complete.

It all begins at the same place: our planet’s largest magma chamber, the outer core. (Marsh, in that list)

Let’s drop in for a visit.


Meanwhile, in the real world, WATCH OUT!

Rocks from great depth have emerged, taking on protective seasonal coloration!

Eclogite is cool and so is the geology of Ring Mountain.

Featured image: Enken/Shutterstock

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