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#lava

3 posts3 participants0 posts today
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Nicole Sharp

Reclaiming the Land

Lava floods human-made infrastructure on Iceland’s Reykjanes peninsula in this aerial image from photographer Ael Kermarec. Protecting roads and buildings from lava flows is a formidable challenge, but it’s one that researchers are tackling. But the larger and faster the lava flow, the harder infrastructure is to protect. Sometimes our best efforts are simply overwhelmed by nature’s power. (Image credit: A. Kermarec/WNPA; via Colossal)

Aerial view of lava overflowing a road and the surrounding landscape in Iceland.
#fluidDynamics#fluidsAsArt#geophysics
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MediaFaro News Digest

Icelandic fishing village evacuated as lava spews from volcanic eruption.

Iceland's famous Blue Lagoon spa also closed after the Sundhnúksgígar volcano started spouting lava on Tuesday and the village Grindavík was evacuated, apart from eight residents who refused to leave.

mediafaro.org/article/20250401

Le Monde · Icelandic fishing village evacuated as lava spews from volcanic eruption.By Le Monde
#Iceland#Volcano#Lava
Continued thread
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Giuseppe Bilotta

Why does this all matter for #lava flow #modeling? Because most probably lava is non-Newtonian. This means that in our wish to determine how its viscosity depends on the chemical and physical properties of the melt, we're not looking for ONE functional relationship (the viscosity coefficient), but multiple ones: for example, assuming a Herschel–Bulkley model we'd need to find THREE such functional relationship: one for the yield strength, one for the exponent, and one for the coefficient. All of these measured on the actual lava flows across different volcanoes at different times and in completely uncontrolled conditions.

As you can see, not exactly the simplest of tasks.

And of course, if we don't have these functional relationship we can't actually model lava flows.

Or can we?

8/

Continued thread
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Giuseppe Bilotta

So, I mentioned already that we cannot really model #lava flows. The main reasons for that is that we don't actually know how lava behaves, at least not in sufficient detail.

Of course, lava is a fluid, and a (very) viscous one at that, so we know that it follows the Navier–Stokes equations. We also know that its behavior is heavily dependent on temperature, so we know that we also need the heat equation, with both kinds of boundary conditions (conduction to ground, and radiation on the free surface).

And that's all we know. Seriously.

OK, not really, but everything else is extremely uncertain. When modeling a viscous fluid (like lava, or any other geophysical flow for the matter), the first thing you need to know is what the viscosity is. And for lava, we don't know. There's a lot of things we do know, but not enough.
For example, we know that the viscosity depends on temperature, chemical composition, degree of crystalization, amount and types of volatiles in the melt, and so on and so forth. But we don't exactly know the laws relating the viscosity to all of these chemical and physical properties.

2/

#NavierStokes#NavierStokesEquations
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Giuseppe Bilotta

I'm going to take advantage of the current #eruption on Mt #Etna to discuss some of the challenges of #modelling #lava flows. Buckle up (or just silence me) because this is going to be a long thread.

First of all, why do we want to model lava flows? The answer most definitely isn't «because we can», since —as I'm going to explain momentarily— we actually cannot. Still having an idea about how lava flows and sets in place is a powerful tool for the assessment (and possibly mitigation) of the associated #hazard and #risk: if we can tell how lava flows, we can tell which areas are going to be reached by the lava, and hopefully also improve the design of tactical and strategic actions that can be taken to minimize the damage.

(Of course, whether or not those actions will then be taken is an entirely different matter, but that's mostly politics, not science.)

1/

#MtEtna#simulation#CFD
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naddel aloha
I love hanging by the ocean on stormy or rainy days 🩶
When the sky is full of dark & scary clouds and the waves go crazy and fill the air with salty sea spray, and the energy is so raw, rough, pure... Makes you feel refreshed, recharged, alive 🤍

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#hawaii #bigisland #ocean #sea #oceanlove #vitaminsea #waves #roughsea #highsurf #surf #water #raw_waters #storm #stormy #stormclouds #energy #pure #refreshing #lava #nature #hawaiistagram
#hawaiistagram
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