A Green Hawaiian Interlude

Helicopter overflight of Kīlauea Volcano’s lower East Rift zone on May 19, 2018, around 08.18 local non-imperial time. Photograph by USGS, used under Wikimedia Commons.

A little article while we happily wait for the USGS to confirm that Kilauea is about to sprout a green caldera lake, or not.

I normally do not write a lot about Kilauea, the reason for this is that it rarely does anything interesting. But, in 2018 it did quite a lot of interesting things, but for various reasons I wrote little publicly about it.

Before we get going on Thursday’s news, let us do a small recap on what happened. At least from a volcanically interesting standpoint, and that means that I will talk about plumbing. Most who read Volcanocafé have noticed that I often write that the edifice is just the erect end-product of the volcano. And that the volcano itself starts where magma is created, in the plumbing that carries the magma upwards.

It is down there in the warm depths that the interesting things happen. To understand a volcano, one must understand its bowel-movements.


Kilauea 2018 eruption

Halema’uma’u crater glowing in the night from incandescence in the lava lake in March 2013. Photograph by TimBray, used under Wikimedia Commons.

Kilauea had been pretty much in a steady state eruptive phase from the 3rd of January in 1983, when the eruption in Lower Puna started on the 3rd of May 2018.

The most famous parts of the 1983 eruption was the formation of the PuʻuʻŌʻō Cone and the 2008 rebirth of the Halema’uma’u Crater inside the caldera.

For being a medium sized eruption from a large volcano, 1983 was a fairly uneventful eruption, at least from a volcanological standpoint. For the residents it was a horrible event as large areas were devastated, and many lost their houses.

In early 2018 I became somewhat intrigued by the changes in the GPS trajectories on the stations facing seawards of the rift, because it indicated that a more radical change was possible.

I was obviously not the only one noticing this, so I quietly pondered what it might have as a result. As per usual the doom and gloom crowd and the Daily Mail crowed that half the island would slide out into the sea causing a megadeath tsunami.

Instead I focused upon what might cause it, and what the effects would be. I surmised that it was caused by magma pressure increase in the rift system leading towards Puna, and that soon the rate of spread would be higher than the magma influx from depth causing a rapid decrease in pressure. And that we would either see quite a bit of earthquakes, or even a large one.

The reason I believed that, was that I had already seen this happen at both El Hierro and at Holuhraun.

In the end I decided to not write that particular article, something that I have regretted since. During this period our commentator Jesper booked a trip to go and watch his beloved lava lake at Halema’uma’u, so I thought that I should write and tell him that it would most likely flush before he got there. He remained a bit incredulous about it for a few weeks, before nature served a particularly big bowel-movement proving my point.

Earthquake distribution map. The red dot is the Hilani Slump M6.9 earthquake. Image created by Phoenix7777 and used under Wikimedia Commons.

Even though the flushing of the magma out of Halema’uma’u and PuʻuʻŌʻō was quite dramatic, and the start of the eruption itself was intriguing, many tend to forget the most important part. The part that happened on the 4th of May at 00.33 local time (12.33 PM for the imperially handicapped Americans) in the form of a M6.9 earthquake.

The earthquake caused the Hilina Slump to move 60cm towards the ocean and slightly downwards. The earthquake happened at 5.8km depth in the intersection between volcanic rock and the old ocean crust.

Now, let us return to the bowels. Imagine that your colon became two feet wider all of a sudden, that would have some rather disturbing effects. For a rather long volcanic rift zone, it means that all of a sudden mother nature needs to fill in a dyke that is all of a sudden 60cm wider, and the only way it could do that was to suck in magma since nature abhors a vacuum. In other words, PuʻuʻŌʻō was doomed, and so was the magma reservoir under Halema’uma’u.

At the top of the rift the result was dramatic as it caused rapidly increased tension on the rift, forcing more and larger cracks to open, and the eruption quickly took off with a vengeance destroying parts of the Leilani Estates.

Obviously, the change means that it is far more likely that the next eruption will occur at the rift part, than in the caldera part, or for that matter around the top of the edifice. Rebuilding the destruction of the magma system that used to feed Halema’uma’u will take time.

It will also take quite some time before the systemic pressure is high enough that far up into the system. Especially since the rift is quite likely to break again as pressure goes up. It will though most likely occur higher up on the rift compared to Upper Puna.


Kilauea in the news

The Eastern Rift Zone of Kilauea. Photograph by USGS, happily stolen from Wikimedia Commons.

The hydrological system of Kilauea has been extensively researched, and that is also true for the area near the caldera. We know that there are aquifers leading to the caldera and the nowadays destroyed magma conduit that used to feed the Halema’uma’u lava lake.

As the caldera floor dropped into the void caused by the rapidly evacuating magma under the lava lake, it caused fresh contact surfaces to form on those aquifers causing a bit of sedate steaming.

Here comes the intriguing part. The general area is extremely hot, so all water should be boiled off for a substantial amount of time, unless of course there is a lot of water gushing forth. The last part is negated by the sedate steaming that we have seen.

This creates a conundrum in regards of the green little lake that is apparently forming at the bottom of the newly formed nested caldera. It should really evaporate faster than it could collect, at least for a few years more than might have happened. Obviously, the lake could be fed by rain, or a combination of rain and aquifer.

I love scientific mysteries, especially those I can’t readily solve. To quote Sherlock Holmes in the interpretation of Banderdick Cuminsnatch (admit it, you too can’t spell his real name); “The Game is Afoot!”.

Another newsworthy little item is that magma is accumulating at the southern end of the caldera at 2km depth. So far it is too little to give hope for the return of a more glowing lake than the green patch of water that we might have now.

Now, time to wait for nice pictures and for the USGS to confirm, or un-confirm the formation of Kōkā’nui’keokeoʻole’nā’honu.



The reason for this interlude from the series about Vatnafjöll is that Andrej has gotten married and started to learn Finnish to understand his computer. Apparently, a fair bit of vodka is involved in the process. In other words, he has installed Ubuntu and is trying to get to grips with how to produce plots on that system.

So, let us give him a week of marital bliss, before we start pestering him for plots of the bowels of Vatnafjöll.




74 thoughts on “A Green Hawaiian Interlude

  1. Speaking of Kilauea, on Sunday it will be one year since the end of the main phase of the eruption.

  2. Thank you for the article – and congratulations to Andrej. (I trust he has not married his computer?)

  3. The lava lake may be long gone …
    But the New Halemaumau pit haves now hot sulfurious fumaroles so magma is indeed accumulating at depth.
    The potential hot freshwater lake in the deepest parts of the caldera are still unclear but HVO says maybe= here is latest on that https://volcanoes.usgs.gov/volcanoes/kilauea/status.html
    Also the 2018 and 1920 s caldera collapse explosions are highly debatable if they where caused by groundwater and likley they where not.
    Halemaumau remains very hot and dangerous to go inside.

  4. Thank you Carl for this update.
    While Im very familiar with this volcano
    I still have a question =

    Do you know how much the 2008 – 2018 lava lake heated up the bedrock – conduit walls in 11 years?
    I knows these thoelite basalts are searingly hot but I also knows that rock have a very low heat conductivity…
    11 years of lava licking the walls and heating the bedrock. When the lava lake drained I looked at the webcameras but the very fluid lava left just a veneer on the shaft down to the magma chamber and that fell away revealing the bedrock behind…

    • I think we need to take into account that countless layers have been laid down under centuries inside the caldera, and that this was just the last lake. So, the combined ground heat would be substantial.

  5. I question how it is possible that a lava lake remains liquid when it clearly does not get a lot of new fresh material from below to bring in heat. Some gasses are boiling off.
    The heat los of a surface that hot (800 – 1000°C) is huge, several KW/m². This heat has to be replaced to remain liquid.
    There is also a serious amount of heat going into the sidewalls of the ducting going up.

    • Halemaumau lava lake was like all lava lakes directly connected with the magma resovair and Hawaii hotspot source below.
      Magma constantly circulated and convected in halemaumaus magma column keeping it open and active. With temperatures of 1240 C it only formed a thin insulating skinn that was rafted and recirculated into the lava lake. Halemaumau was a large lava lake too and that meant alot of heat streaming up from conduit.
      Rock is a poor heat conductor so halemaumaus slow convecting mass just keept open and active

    • Halemaumau just before draining: worlds largest lava lake when the photo was taken.

      Wonderful circulation here in this photo
      These crusts moves across the lake as minatyre plate tectonics “lava lake tectonics”.
      The lava lake haves a surface temperature of 400 c in the grey crust and over 1215 C n the molten lava.
      The lava wells up at the south end of the lake and then moves across the surface where it sinked down at the northen edge. Its a circulation convection that keeps these lava lakes open and permanent and keeps them mostly from spilling over. Its huge… here the lake is bigger than a large sport stadium.

      The lava is feed from the conduit and rise up in the lake
      Then it haves to recirculate sink down at the edges or in this case the lakes northen part where the webcam
      was. The whole thing is circulating

      • Jesper, not an expert but have observed steam heating water to boiling point. What if it’s not so much lava circulating up and down the volcano’s supply tubes but incandescent gas rising through the very hot lava at depth and transfering the heat as it expands in the relatively low pressure environment of the lava lake.?

        • Carl since Im acually a bit Dyslextic
          What does Graham try to say here?
          Maybe you can give an answer?

          Hmm gas heating a lava lake
          No the magma inflow itself is what heats kilaueas lava lakes

          The gas content/ magma supply may effect how fast it rises and how calm the lake surface is

          • Halemaumau was a very large lava lake with a mostly very calm surface with well developed crust

            But circulation in halemaumau was quite fast and the crust was very thin and flexible

        • I’m pretty sure that you will find the thermodynamics of gas heating the magma to be very unworkable. The specific heat capavity of the gases are vastly different than the magma.

          Due to the different densities, the gas is effectively lost to the system once it reaches the surface. It does however, contribute to the overturn of the lake.

          Opinion: The primary energy transport is the liquid magma, not the gases.

          • That is correct. The heat capacity of gasses are very low and even at very high temperature, they are inefficient at heating. However, heat capacity is much higher above the critical pressure. Liquid water, in contrast, has higher heat capacity than rock so that heats quite effectively. The fact that the new green lake is so hot may suggest it circulates through the rock.

    • The lava wells up at the south end of the lake from the conduit… then it moves across the lake.. looses gas and cools ever so little and sinks down at the overlook vents northen parts … returning to the magma column circulation and the chamber
      Whole thing was circulating : )

      • Jasper with the greatest of respect the lava lake is RIP for the foreseeable and has been for over a year now. No need to keep waffling about it bro.Thx

        • Yup its gone
          Now its a freshwater lake instead
          I never seen a volcanic water lake in Kilauea before

          • Is the term ‘Fresh Water Lake’ a bit generous. Is ‘Puddle’ more correct?!

          • I am dubious about all 3 words.
            The fresh part goes out the window since it contains so many things poisonous. Same goes for water, it is more a suspension of nasty crap.
            And lake… well, not so much.

            Stinkemulsion Piddle Puddle would be more correct. 🙂

          • It looks very much like seepage from the water table to me. Definitely not a lake: it is far too small. The next step down is a pond. But even that might be generous. Puddle may indeed be appropriate.

            The colour is quite spectacular. Probably Fe2+, at a pH of 1-3 but at moderate temperature (no hydrothermal activity). It is similar to Kelimutu:
            https://www.volcanocafe.org/kelimutu-the-magic-of-colour/ Rain will likely dilute colour. That is why I think this is ground seepage.

          • Stink lake it is
            Carl what woud happen if one swimmed in it?
            It appears below boiling point and is probaly quite cool as this is the most solid part of the caldera rubble

          • There is quite a good chance of us getting a cooked Jesper that rapidly dissolves in the extremely low ph of the lake. Basically that is most likely sulphuric acid solution.

  6. Thanks for the article.
    Yours are very easy to read cause of the short clear paragraphs (my english is not that good, a necessary reread of the short paragraph makes it easy to understand the text). 🤔😊 Great!

    To Topic: How much rain mm or inches does fall at Hawaii in a year?
    And how large would the area be that could feed the sink/hole in the caldera?

      • Only example I found on thr Big Island is near Mauna Kea: Waiau Lake. Feeding area about 0,5 km2… annual rainfall 200 – 750 mm.

    • The village of Volcano, which is very close to Kilauea Caldera, gets over 122 inches/3098 mm. Which is certainly a lot.

      A lake could potentially form inside the newly sunken part of Halemaumau. I think lakes did indeed form in Halemaumau or even other parts of Kilauea Caldera in the past, probably as recently as a few hundred years before and maybe just before the explosive eruption in 1790. I can’t remember off the top of my head right now for sure.

      • A well is located just to the south of the crater and allows to measure the depth of the water table, it is usually around 600 masl. The view of HVO is that when the caldera falls below that level a lake of water forms and causes eruptions to be more explosive, geologic evidence supports this. It may have happened after the caldera formation around 1500 . Some publications suggest that a lake of water existed before the 1790 eruption, so it could be but I don’t know of any conclusive evidence.

        The deepest part of Halema’uma’u Crater has collapsed a bit below the water table of the nearby well, 50 m or so. I doubt though that the water table level is even around the caldera, a lot of dikes cross the area from W to E and SW to NE, since they are not permeable they can impound aquifers leaving diferent water table levels on each side so it ends up being quite complex.

        In any case the lake is probably going to stay, and likely fluctuate in size and grow a more until some eruption vaporizes it.

        • Can you say phreatic? I knew you could. 😀

          Unlesd, of course, the magma return is slow enough to evaporate it first.

          • If the magma rises through a dike into the floor of Halema’uma’u it would be fast and probably not give the lake much time to vanish before the eruption, and then I guess one does get a phreatic/phreatomagmatic eruption, maybe even toss some fridge-sized refrigerators around. HVO will probably explain some future scenarios soon.

            HVO has released a new volcano watch article, about the lake of course! https://volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html?fbclid=IwAR3YqyYj4TZP6ivu51v4oUV-tR1rxuO-Nvhz4ktt880il15n7zlhIfPEEj8

            He mentions the exact depth of the deepest part of the caldera is 68 m below the water table of the well and also talks of maybe a new webcam that will have the lake in sight.

            TS Erick dumping some heavy rain on the island right now, and Flossie is on its way. It also seems to me that the new lake is getting bluer day by day

    • Really close to Krakatau. Haven’t checked since last night.
      Was watching the Agung cam, they could feel it all the way in Bali as a weak quake but the epicenter was off Banten.

  7. RCOD, DAND are showing some indigestion. I am thinking that this might be due to the weather or waves from the storm.

    • Likely. During one of our past landfalling T Storms I set up an accelerometer to try and detect the waves battering the shore. All I got was an enhanced noise floor.

      I can now run dual sensors and can probably “aim” the set to dig out vibrations coming from the coast, but have no storms to try it out with… but I’m not complaining.

  8. I was doing a grav survey when remnants of a hurricane passed through. What I saw in the dial of the L&R was a low frequency oscillation very similar to the ones that happen from teleseisms of large quakes. Like in that situation, I got the day off.

  9. Ulawun seems to have a massive one, ash at 63000 ft according to Darwin?

      • 1 hour eruption to 63,000ft so strong but not a major VEI 4 this time. The ash cloud is already dissipating.

  10. New heat record on the Greenlandic icesheet (Summit weatherstation 3202m above sealevel) on Thursday the station recorded 2,7C beating the old 2,2C record from 2017. On friday (yesterday) however, that record was shattered when the temps reached 4,7C.

      • It appears that July 2019 was just about the hottest ever. This ties it with July 2016. However, 2016 was a strong El Nino which raised temperatures worldwide. This time there is no excuse. Global warming is here. Older people have little to worry about, but our children will live in a very different world from ours. I just hope that some people will come to their senses before it is too late.

        • Co2 is Rising at alarming rates
          We humans release as much co2 as a Siberian Traps did every year through industrial activities

          • How things aught to be? To be alive is dangerous, I might cure the world of CO2 and in the mean time get hit by a runaway milk truck. Maybe this is the doom we we set out from the beginning to encounter that or something far more sinister. Science doesn’t say anything about humanity continuing forever does it? I doubt it will. Pick your poison, if failure doesn’t kill us success surely will.

          • We need 800ppm to maximise plant productivity. The small amount of warming it causes still probably won’t be enough to stop us plunging into the next ice age.

          • Turning part of the planet into desert hardly increases plant productivity. Models show that the effect of rising CO2 is more than offset by the lack of water, as ground dries out though higher evaporation. Dream on.

          • Let’s not forget the effect of temperature on the enzyme activity in the various temperature dependent reactions and cycles of photosynthesis. If it gets too high the enzymes denature.

          • [Just] “as much co2 as a Siberian Traps did every year”

            But no where near the amount of fly ash…

          • As the world gets warmer the seas warm and humidity rises and rainfall increase
            During greenhouse eras before man, earth is covered by forests.

            Its during the Ice Ages the deserts are most happy: cold and dry
            Rainforests almost dissapeared in the glacials

            But now man is destroying the forests
            I think this is better in a VC Bar diskussion too

          • This is only true up to a point. During the hot houses of the Earth climate, large parts of the continents were sand deserts. Rainfall increases, but so does evaporation, and whereas rain may increase in some places, evaporation increases everywhere. You have to look at the predicted weather maps: where do the rain belts move to (the Amazon is predicted to become drier; the Middle East already is), how much of the rain is episodic (a single tropical storm is not helpful – you need rain over a longer period), and (in the temperature zone) is it summer or winter rainfall? How fast are the changes?: if it is too fast, the local vegetation can’t adjust: forests take a long time to grow.

            I am an optimist: global warming is a solvable problem, by mitigation and adjustment. But it can only be solved if people are willing to open their eyes.

        • During the PETM
          There where no deserts Albert
          Eocene was a humid steamhouse bath
          A climate that I enjoys

          Eocene was a world of rainforests

    • “Never underestimate the bandwidth of a station wagon hurtling down the interstate loaded with mag tape”

      I’m just impressed with the heat shield.

  11. For those of you who do not live in Britain you have to understand the headlong crash into trying to reduce CO2 emissions which we are doing but at high cost. Better than most in fact. However the mindset of journalists, the public and politicians is that we (in Britain) can have any significant effect on world CO2 production and we really cannot. The big players are asia and south america (and africa is doing its bit too).

    Really most of it is down to increased populations combined with new industrialisation and that isn’t going to slow any time soon, fact.

    The result, possibly much more quickly than even the doomsayers think, is going to be mass population movements combined with massive famines (hopefully not pestilence as well). Rising sea levels will remove big chunks of the best arable land and destroy major cities worldwide.

    So in my opinion it is at least as important to prepare for much higher sea levels and climate changes that mean current local farming methods may not be effective. The latter means variable and lower harvests simply because the crops planted are no longer well matched to the new environment.

    I’m afraid I am probably in the small group of humans who have had the best life since the dawn of time, born in europe circa 1950 we have had rising disposable income and a nanny state looking after us from birth to death and we have had no wars we couldn’t avoid by not signing up. Our children and definitely our grandchildren, will live more challenging times.

    So Albert is, sadly, almost certainly correct.

    • It is not Britain alone that are seeking to reduce CO2 emissions. The whole of western Europe is doing the same. China too is on the way there (albeit from a dreadful start). I don’t see Africa as much of a problem (limited industrialisation) but Brazil is having a good attempt at destroying what was the largest rain forest in the world. I believe that Homo Sultis will die but some of Homo sapiens have a chance of some form of survival.

      • California is restricting emissions (we have a zero emissions law and a lot of electric cars and solar power) never mind what the rest of the country is doing.

    • I hear you, but others not doing something good and sane is not an argument for not doing it yourself when you know it’s the right course. Knowing there’s a big problem and ignoring until its too late is never a good idea, and we’re setting an example for the countries that are behind us on the curve.

      In addition, the “headlong crash” is already having benefits. Fewer people are dying of coal lung and associated diseases, to give one example. Fewer people have to live with the awful air, ash waste and water pollution that the old power stations pumped out. I personally have seen primary schools near a large coal-fired power station (thankfully now closed) where almost every kid had an asthma huffer, and that was a modern one that was touted as being “clean coal”. Power cuts for me have become even more rare than they were.

      There’s also a much bigger future benefit. I believe and hope that each region and country will have its own wake-up moment, when the light goes on and they realise they do need to do something. When that happens, it’s unarguably better to be amongst the countries that have the experience, expertise and manufacturing capacity ready to sell the solution to them.

      Always remember too, the money spent doing this, on top of the examples above, doesn’t disappear. People are employed to study, plan, implement and manage this stuff. Roads are better in rural areas near me because installing wind farms needed them. The electrical grid is being expanded and invested in to handle the newer, different supplies and demands.

      I also want my daughter to know that my generation did something different and better than the boomers, to give her generation at least a fighting chance of a decent future.

      • I agree with you on coal.

        The rest of the response is in the bar.

    • Follow-up, now I’ve had a coffee and a chance to read your post more carefully…

      Sorry if it seemed like a rant to you. I feel strongly about this, and get frustrated with people justifying getting in the way of progress based on whatabout-isms.

      • Please take a AGW pontificating, casting downward glances at your neighbors and smug criticisms to the bar and relax. We’re all going to die sometime no matter what. 😇

  12. HVO has a new update on the puddles at the bottom of Halema‘uma‘u – definitely not a place to go for a swim (or splash):

    This video shows steaming from the main pond of water at the bottom of Halema‘uma‘u as captured on Sunday, August 4. Two smaller areas of ponded water were present a short distance east of this spot. Thermal images indicate that the water surface is roughly 70 degrees Celsius (158 degrees Fahrenheit). USGS video by M. Patrick, 08-04-2019.


      • That is quite revealing. Note the evidence for steam also a bit in the foreground. The sides look like collapse, so probably fairly lose. i think it is water seeping down within the collapse. The colour shows it is picking up minerals on the way, and the steam from the side shows a bit of water underground there. It may be collecting because the rocks along the slope have cooled down a bit, so water no longer fully evaporates while it percolates through. Depending on the weather, we may expect that the lake will grow a bit more.

        The rocks underneath are probably still too hot to allow the water to penetrate down, so that should be ok. The biggest risk is, I think, that there is a further collapse which buries the lake. That would increase the risk of a steam explosion. It would take a big explosion to hurl rocks over the edge of the caldera, but I wouldn’t feel fully confident that it can’t happen.

        • Most Keanakākoʻi eruptions (the explosive events ~1500-1790) involved fresh lava, with the notable exception of 1790 which was almost purely wall-rock material. That suggests most of them were driven by magma reaching the surface through a lake or groundwater.

          Another hazard are pyroclastic surges, many of the Keanakākoʻi eruptions included these, they were usually weak, usually not going very far from the west and south rims of the caldera, but a pyroclastic surge killed many native hawaiians in the November 1790 eruption so they are not to be underestimated.

          Meanwhile the lake is certainly growing. now with multiple small ponds probably about to merge.

  13. The geothermal hot green lake grows larger and larger

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