[sixothree]

This may be a dumb question but near me is a cement factory that (incidentally) makes stackable concrete blocks the size of a car. They stack them multiple stories high and multiple blocks deep, at least while being stored at the factory.

What about lava makes it so we can’t redirect the flow around neighborhoods with these things?

[meheleventyone]

There is a berm that got built around the north of the town but unfortunately the fissures go under the town. The initial eruption came across the barrier so a lot of the lava has been diverted. The second eruption was inside the barrier so not a lot can be done. If you scroll down the linked page there’s a map of the flow and barriers.

There’s footage of them saving the machinery being used to build the barriers.

[fanf2]

Look at this webcam feed overlooking Grindavík https://www.youtube.com/live/hvcP4kVVOnk

Go to about 11:58 on the timestamp in the bottom right corner, you will see the lava flowing along the berm (which is doing a good job of protecting a large building) while workers with bulldozers and diggers close the gap in the berm that the road goes through.

The fissure close to the town opens up at about 12:20. The lava flowing behind the berm reaches the road at about 12:50.

[yownie]

fun lil video from a friend here of the evacuation of the heavy earth machinery that almost got swallowed up this morning by the flow.

https://xn--lofll-1sat.is/@briansuda/111753899635044640

[sixothree]

Thank you

[ceejayoz]

They did exactly that. It worked great, but this new fissure is lava that went under.

See https://imgur.com/a/7WGO9M6 ; yellow are the defensive lines. Red are the fissures. Black is the lava; you can see how well it was redirected.

[fanf2]

Working link — https://en.vedur.is/media/uncategorized/Kort_StadsetningGoss...

From https://en.vedur.is/about-imo/news/a-seismic-swarm-started-n...

[ceejayoz]

Sorry, fixed my link. The semicolon broke it. https://imgur.com/a/7WGO9M6

[sixothree]

This thread is really the closest I get to lava or lava knowledge so this is very helpful actually.

[dahart]

In this case, I believe it’s that the eruption is getting bigger and lava is seeping out of new & unexpected places in the ground, thwarting the existing redirection barriers. They do have some flow barriers, but the lava is oozing around them. They were hoping it wouldn’t come to this, but at some point, if the eruption gets big enough, lava barriers become pointless.

[kabouseng]

Lava is molten rock. Concrete blocks are rock.

[ceejayoz]

So is the ground it comes out of and runs over. It doesn’t instantly melt rock it comes into contact with.

[ygra]

Also from the blog:

> Benedikt Halldórsson of the Met Office says houses are not designed to withstand lava flow.

> »... You can expect the walls to give way from the load, and the heat in the lava is such that it burns everything in its path.«

Apart from the heat, since it's molten rock it also has considerable mass, and the lava flow continues pushing from behind.

[jon_richards]

One weird realization I had is that lava is over three times as dense as water, so if you tired to “swim” in it, you’d basically just sit on top.

[s1artibartfast]

it is less about density and more about viscosity, which depends on the type and temperature.

I had an opportunity to interact with lava during a Hawaii eruption, and people could run/walk across red hot and flowing lava, but it would start melting the bottom of your shoes. This lava was definitely on the colder end of the spectrum, with a consistency like bread dough.

On the the other end of the specturm, there are very hot low viscosity lavas similar in consistency to soup. If you tried to step on that, it would be like falling into a pool.

[BenjiWiebe]

You'd only keep sinking in until you had displaced your mass in lava. Which would happen sooner than in water.

[ceejayoz]

“Sit” might not be the right verb here.

[dylan604]

That's not what happened to Gollum

[sixothree]

I'm not really sure what you mean by this. But I'm guessing that you really have no clue what would happen.