Directing Lava West of Grindavik? a Topographic Perspective

[@MHarenArt]

Excellent visuals, thank you. This stuff is all pretty fascinating! Yes, seeing the topography makes it self explanatory. I personally don't see how the town can be safe for a very long time. The situation is just to volatile and unpredictable.

[@geomechanic]

Glad you enjoyed it!

[@Jeo81]

Thank you for the update!

[@geomechanic]

Our pleasure!

[@MariaM-fc8pp]

very insightful - thank you !

[@geomechanic]

Glad it was helpful!

[@williamlloyd3769]

The towers you mentioned were US Navy LF and HF communication towers that were associated with Naval Air Station (NAS) Keflavik that was decommissioned several years ago. Surprised the towers are still standing but perhaps still in use.

[@geomechanic]

Thanks for the information on the towers.

[@skippern666]

The infrastructure west of town is a Navy Radio site, it is most likely remotely operated, but a lava flaw through it will pull it offline until antennas are repaired and re-connected.

[@geomechanic]

Thanks for informing us.

[@jimjimgl3]

Thanks for the post. So interesting how you can manipulate google earth data! I think, though, one of the bigger issues for Grindavik, besides the direction of lava flow, is the non-eruptive fissures opening up in town. I would not be surprised if the town is, sadly, condemned for residents.

[@geomechanic]

The open fractures (non eruption fissures) will be a big challenge for the future as their location underground is difficult to determine.

[@MVargic]

What website/software do you use for the topographic view?

[@geomechanic]

I used this source to get a nice coloured image for the video: en-us.topographic-map.com/map-f2xd3l/Grindav%C3%ADk/

[@matsdeurell7347]

Thanks, excellent pedagogical! According to Bard AI, Icelandic and Japanese researchers have experimented with water-filled (non-nanotubed) ceramic 6-10m high barrier sections for use in towns to divert lava, but that no decisions are made about production. Do you know anything about what start up time with infinite funding would be needed for such an attempt to flow divert through Grindavik, and thus in any such situation in the future?

[@geomechanic]

Very interesting. I am not sure what it would cost. I would have to look into it.

[@benjaminhanke79]

That Transmitter has an Wikipedia entry. The "Naval Radio Transmitter Facility Grindavik is a transmission facility of the US Navy"

[@geomechanic]

Thanks Benjamin.

[@orelonsidney724]

How much lava would have to flow into the harbor before it becomes compromised?

[@geomechanic]

I would have to look at the Bathymetry (underwater topographic information) and make an estimate. Depends on the depth and the size of the ships that currently use it.

[@krisslarson443]

The communications towers are for maritime comms. The highest tower is a low frequency comms tower for submarines at 37 kHz operated by the Icelandic Navy withe the US Navy The lower tower to the east of it is a NAVTEX 518 kHz station that broadcasts maritime weather by radio teletype. The smaller towers to the south are HF comms either to the NATO navies or civil merchant marine.

[@geomechanic]

Thanks for the information on the towers Kriss Larson.

[@WalterWeakley]

Did everybody miss something, the eruption started in the north and erupted to the south in very short intervals. next will be inside Grindavik and then further into the sea. these tectonic plates are very huge and will move apart in an area of 18,000 km. it is also likely that the crack closer to the airport will open soon. the main fault entering Iceland in the south is between Grindavik and the airport. the town is built exactly in the wrong place. next eruption will be inside the town. we all hope this will not happen. eruptions are creeping closer and closer to town and this will not stop just because there is a town. one lesson is that the barriers can burst open as in the case of the greenhouse near miss. barriers are supposed to be built in line with the eruptions with a slight left or right offset, not to be built as a direct stop.

[@williamlloyd3769]

The Iceland, The Book of Settlements, mentions that Grindavik was founded by two settlers in 934. It was a natural harbor. Over 1000 years is a pretty good run for any town. Agree that it is likely the next eruption will probably wipe out town and harbor in the future. PS - the earthquakes and the hidden crevasses that are now exposed will probably make the majority of the town uninhabitable.

[@MrKorton]

Nope, the eruptions are pretty unpredictable according to icelandic geologist, so inside the town is not a sure thing like you're saying.

[@geomechanic]

I agree with Mr. Korton, the exact location is hard to predict. As the town is on the coast, the geology, topography, and other factors that influence the magma pathway to surface also change from that where the other fissures opened. It is really hard to predict until ground uplift and earthquakes begin to occur.

[@WalterWeakley]

over the medium term,, we have more evidence of the locations of eruptions, starting in the north and systematically erupting southwards, currently, Grindavik has earthquakes as we speak including the opening of the cracks in the town itself@@MrKorton

[@WalterWeakley]

there is opinions and there is facts@@MrKorton

[@confucious_of_babbel8481]

You gotta make a ditch then use extra dirt for berms on the ditch. It should then funnel lava where you want.

[@geomechanic]

A ditch in town could be helpful with protective berms as well. It would work for a short eruption at least and perhaps that would save some homes.

[@silvasdamata]

The reason berms are better than ditches is that lava can extend in the direction opposite the berm as long as topography allows. A ditch is always extremely limited in volume, it will fill up very quickly. Lava doesn't flow like water - it solidifies even as it moves downhill, and by the time it reached the ocean (or the end of the ditch) it would be overflowing upstream.

[@silvasdamata]

@@geomechanic Considering the entire free space that goes across town, downstream from where the fissure erupted, it could be possible to scrape the ground from the middle to the sides, in effect creating a wide ditch with side berms that could allow, as you say, a limited amount of lava to flow through in a short eruption. The problem is that you can't guess where a fissure will erupt, such as the one that erupted in town this time. The berm they built proved its worth, as for fissures erupting closer to town, or inside the built area, there's just no sensible thing to do, is there?

[@Justme--]

I believe from reports the ground itself in Grindavik is to unstable to dig , with sinkholes and fissures and cracks appearing throughout the town.

[@robertslugg8361]

I posted this idea on Shawn's site about 6 weeks ago, but as an angled ditch from Hagafell down to the small Bay to the east of Grindavik. My opinion is that the dyke they built was a short term option that will end up having long term implications since they are simply putting new lava behind a barrier as opposed to directing it to the sea in the first place. At some point I envision the lava backing into Blue Lagoon and the Power Station. Once lava is directed, it will use that inertia to keep going, as we witnessed at Litli-Hruter where it flowed 10M above the surrounding terrain because it continued to flow and reinforce the initial channel. Slowing it down with a perpendicular wall and allowing it to cool in place worked once and mostly because the flow stopped when it did. If the northern area erupts again and that lava has any momentum it will top the new walls and continue into town, whereas an angled trench/berm would redirect to the Sea.

[@samiatobdjli2149]

À Alger la température était de 12 degrés, mais en 3 jours , elle est passée à plus de 25 degrés. Les climatologues ont expliqué , que c'etait dû aux effets de ce qui de passe en Islande ...

[@geomechanic]

The fissure eruptions recently in Iceland has not produced a lot of ash. A lot of ash can cause a decrease in temperatures.

[@danduzenski3597]

1957 photo a fake? Walter Weakley.