The VC Bar

Welcome to the Volcano Café bar, a place for all things on or off topic and inane ramblings. There has been a need of late to find a place better suited to various theories, long comments and enthusiasm. This page will be less moderated than the main article pages and cleared out every month (this may change depending on use).

Have fun and don’t forget to tip the barman 😉

1,559 thoughts on “The VC Bar

  1. Video of someone walking to the top of fissure 8. Much hiking boots on pumice sound effects.
    Some plants growing already.

    • Wow look at the lava flow at 08: 44
      This stuff is extremely fluid as Kilaueas basalts tends to be. One of the lowest viscosities for any sillicate lava

      • So, corollary is that you’d find *no* lave tunnels / caves at eg Yellowstone, Toba, Ngorongoro etc calderas, unless upstream of a distinctive lava flow from later ‘flank’ eruption ? Very different ingredients, very different eruptive processes…

        Sorry, not being pedantic, just doing an ‘either / or / xor’ sanity check on a possible story plot-point…

        “Yeah, that big caldera would give us hot springs and lots of solar-facing slope with a couple of fresh springs, but forget about finding any lava caves. At least the wall is ‘breached’ so the lake has drainage, unlike the Big Ng…”

        OT: FWIW, I vaguely remember reading that Easter Island has a bunch of lava tunnels and caves along the coast…

    • The second most energetic event is a M 4.3, which is far below the main 5.5. This suggests a tectonic mainshock-aftershock distribution, as opposed to a volcano-tectonic swarm which usually produces a flurry of earthquakes where the most energetic events are close in magnitude to each other.

      The IGN estimates a depth of 20-29 km for the earthquakes, and the location just outside the volcanic edifice makes it very similar to hawaiian flexural earthquakes so probably it is the same process (the lithosphere sagging due to the load of the volcanoes).

    • IIRC, several bunches of now-separate Med islands were merged, sundry straights significantly narrowed. But, though depth over Gibraltar Sill was much, much reduced, it would still be a sea-way. Between the end-Messinian mega-flood’s old scour trench, Atlantic tides and storms, the gap stayed open.

      ( Um, don’t know about Red or Black Seas. IIRC, both are grimly disputed… )

      IIRC, Med currently needs equivalent of ~1 metre Atlantic water per year to balance river-fresh vs evaporation. Gib in-flow is significantly higher as there’s a briny bottom out-flow. Balance during glacial eras depends on so many factors across region I wouldn’t know where to start. Also, IIRC, several large-ish rivers cut across what is now Central Sahara…

      Harking back to the Messinian Event, when vast, kilometres-deep river canyons eroded (*) and were subsequently back-filled with sediments, I’d suggest each glacial low-stand probably carved into the top 100~~150 metres of sediment. There may be much ‘terrace’ info to be found, but my Google-Fu hath fallen short…

      One curious ‘gotcha’ may have been an up-tick in coastal Med volcanic eruptions, as coastal plains were ‘off-loaded’ by the low-stand…

      *) Nile’s mile-deep at Cairo ? The ‘Notch’ beneath Aswan High Dam ??

      • Mediterranean salinity crisis happened before the glaciations
        That was the end of Miocene
        The first cenozoic european glaciations happened at start of Pleistocene
        Lowering of the atmospheric CO2 is one reason for Pleistocene glaciations

        • “Mediterranean salinity crisis happened before the glaciations”

          Yes, yes, and the Messinian flood(s) created vast scour channels which would later help to keep the Med open…

          Likewise, the sediment in those Messinian river canyons was vulnerable to erosion during the glacial low-stands, hence my comment about terraces…

          • Mediterranean was much colder and more arid during the Glacials than today. Only 30 000 years ago

            It may have never frozen but..
            Northen Mediterranean probaly was as cold as Norway sea today.

            Sourthen Mediterranean Probaly was as cool as English Strait, South North Sea is today.

            The landscapes around, where temperate dry steepe
            and steppe tundra in the more northen parts.

          • Nik
            Glenveagh National Park In Northen Ireland, coud be a good analouge How example Spain and Greece looked like during the peak of the ice age in vegitation wise and temperature at least

            Imagine an open, windy landscape thats treeless and fairly dry.
            Summer + 18 C winter – 5 C
            Ice Age South Spain


    Wonderful video showing how extremely fluid Nyiragongos lava lake is.
    Watch it in HD.

    Nyiragongo is extremely fluid, notice the lava bubble gas bursts at 0:36 – 0:43
    Extremely fluid and runny this lava is.
    This is Nephelinite lava, an ultra-alkaline, ultrabasic magma composition.
    The sillica is only 35%for Nyiragongo and its around 1200 C.

    The most sillica poor- sillicate lava on this planet, and the worlds only erupting Nephelinite volcano.
    Very small ammounts of partial melting in the mantle is required to form souch alkaline sio2 poor lavas.


    Another good Nyiragongo video, filmed by the same person.
    Very fluid weird alkaline sillica poor lavas.

    Watch 4:23 – 4:34 waves of molten rock.
    This is now the worlds largest lava lake, since bit larger Halemaumau drained.
    But Nyiragongos lava lake seems to have stopped growing larger.

    But its rising with the years, the lava lake have now reached platform 2 ( terrace 2 ) and soon will reach platform 1.
    Every overflow raises the crater floor in Nyiragongo.

      • I recommend that you don’t try.. It is possible to walk on viscous lava flows, but you need to be fast as shoes do melt. (And you need solid boots to start with.) Imaging walking on the lava river of Leilani. You can’t.

        • Nyiragongo and Halema’uma’u are fluid as heck .. very runny
          These you sinks down in instantly a bit, despite the density
          Impossible to walk over!

          Albert another question: the extremely fluid lavas at Halemaumau and Nyiragongo woud make excellent ash trays right?
          Souch runny lavas must mold itself into details very easly indeed.
          Smooth molds?

          Etnas lava molds and ash trays always comes out rough and poor in detail

          • Albert woud it be possible to blow glass with example Nyiragongo and Halemaumau? These lavas are extremely fluid and often spatters into huge glassy sheets.
            Ocean entries forms nice glass bubbles sheets called Limou – Pele

            Nyiragongo and Kilauea are very smooth and runny
            Woud it be a good glass blowing stuff? or is it too much inpurities and too little sillica ?

          • The extremely fluid smooth lava in Halemaumau: is that a good glass blowing material?
            I imagines it to be that

            But its probaly rather brittle because of the low sillica and lots of inpurities

  4. Nice little group of quakes near Magna Utah Looks like aftershocks from the 5.7 (bottom of the list)

    5km NNE of Magna, Utah
    2020-03-18 14:07:53 (UTC)
    8.8 km
    2km NNE of Magna, Utah
    2020-03-18 14:06:12 (UTC)
    -2.5 km
    5km NNE of Magna, Utah
    2020-03-18 14:05:04 (UTC)
    7.5 km
    7km NNE of Magna, Utah
    2020-03-18 14:01:46 (UTC)
    6.7 km
    2km ENE of Magna, Utah
    2020-03-18 13:48:01 (UTC)
    9.3 km
    6km NE of Magna, Utah
    2020-03-18 13:47:44 (UTC)
    -0.5 km
    5km NE of Magna, Utah
    2020-03-18 13:36:38 (UTC)
    10.6 km
    7km NNE of Magna, Utah
    2020-03-18 13:36:24 (UTC)
    9.3 km
    7km NE of Magna, Utah
    2020-03-18 13:32:29 (UTC)
    3.0 km
    7km NNW of West Valley City, Utah
    2020-03-18 13:31:18 (UTC)
    8.9 km
    5km NE of Magna, Utah
    2020-03-18 13:29:55 (UTC)
    -3.2 km
    6km NE of Magna, Utah
    2020-03-18 13:27:20 (UTC)
    8.7 km
    3km NNE of Magna, Utah
    2020-03-18 13:23:20 (UTC)
    -1.6 km
    6km NE of Magna, Utah
    2020-03-18 13:22:01 (UTC)
    -3.2 km
    7km NE of Magna, Utah
    2020-03-18 13:18:28 (UTC)
    6.7 km
    5km ENE of Magna, Utah
    2020-03-18 13:15:55 (UTC)
    8.8 km
    6km NE of Magna, Utah
    2020-03-18 13:15:11 (UTC)
    7.8 km
    4km NNE of Magna, Utah
    2020-03-18 13:14:06 (UTC)
    8.4 km
    6km NNE of Magna, Utah
    2020-03-18 13:09:31 (UTC)
    10.6 km

  5. The tilt measure southwest of Kilauea is continuing to increase. And it is a large and fast change. I am wondering whether it is instrumental, as nothing else shows anything similar.

    • Albert
      Look at HOK between Kona and Mauna Loa. I have no idea what this means, this is the one of the few times I have ever looked at it. I see that IKI has turned its trend. Maybe a deep intrusion? I guess there is a reason that they installed this tilt meter there.


      • The tilting at SDH is enormous and doesn’t match with what the GPS and the 2 properly working summit tiltmeters are showing so I would say that it is instrumental.

        With HOK it is harder to tell since there is no other way to constrain deformation in that area but perhaps it is the same instrumental failure as in SDH because it looks similar, it shows a continuous rate of tilting that should not be there.

      • That one seems more plausible. It shows the inflation of Mauna Loa which is still continuing.

        • Yes but the tilting at HOK is unexpectedly strong. MOK and SLC are much closer to the summit where inflation is centered and show a more or less stable tilt with changes that do not exceed 2 microradians/month. Compared to the 6.5 microradians the 0 component of HOK has gone up in a month. Inflation at the summit is not enough to explain the rate of deformation down at HOK

          • It may be wrong. But the tilt is not inflation: it shows the difference in inflation between two points. Above the inflation magma chamber, inflation is uniform and tilt does not change. To the side, tilt changes much more. How far away you need to go for the tilt to be strongest depends on the depth of the magma chamber.

            The rift across Mauna Loa can also cause tilt changes, and some of the tilt instruments measure this. And the caldera can sink or rise and this affects local instruments. HOK is further away and would only see the larger-scale inflation.

            Because HOK follows the summit GPS movement fairly well, I am inclined to give it the benefit of the doubt.

          • An interferogram can shed some light into this, where the fringes are the closest to each other would be the area of strongest tilting, or it would be if the interferogram just showed the upward movement. Since east is also toward the satellite it complicates things but it can still be useful.

            HOK is outside the area of deformation created by summit inflation of Mauna Loa, so it actually shouldn’t be affected at all. SLC also seems to be outside the area of deformation but if the interferogram is displacing the inflation towards the east due to the looking angle then SLC might be slightly affected. The best positioned tiltmeter turns out to be and not suprisingly MOK.

            And lastly, the rifts would only create deformation if a dike is intruded into them, unlike the ERZ of Kilauea the rifts of Mauna Loa do not have permanent conduits within them, they depend on the summit sending dikes, except for the uppermost part of the SWRZ which does have some magma storage.

          • Good points. The southwest rift zone did have inflation up to last year (if I recall correctly), after which it moved to an area close the summit. There were earthquakes in the rift zone, so some intrusion has been happening. But it is like Hekla: first activity is at the summit and the rift zone follows some hours later.

        • The tilt at JKA has also made a move. I have not looked at this instrument in months. Looks like it started around the 15th/16th maybe with this quake.
          2020-03-16 07:16:37 3.2 -1

          At the beginning of March both 290 and 20 were about zero, now +2 and -2 microrad. Maybe some localized fresh magma in the rift zone with the uptick in activity in the area.


          • If it is inflation then it should become noticeable in the GPS JOKA in some days time.

          • The tilt would indicate downrift inflation so it would also result in westward movement if it turns out to be magmatic and not some other signal like weather

          • Well, If we needed to open up some rifts to allow some flow these last few over the last couple of days may have made some cracks. Most likely these would be local short lived intrusions, if anything. Aftershocks.

            2020-03-21 17:08:41 2.5 2.3
            2020-03-21 16:55:01 3.2 0.2
            2020-03-21 15:07:00 3.6 -0.5
            2020-03-20 23:45:19 2.1 4.2
            2020-03-20 21:51:36 2.2 2.4
            2020-03-20 12:04:58 3.3 6.5
            2020-03-19 16:48:10 2.6 6.2
            2020-03-18 04:20:49 3.2 6.1

            All off them kind of in line between the ocean and south of a line from Mauna ulu to Puuoo.

          • Those are in the south flank faults of Kilauea, it may just be the routine stress release.

          • JOKA is a little up and west, but we are talking a wee bit .02 meters. I will check back in a few days since this may move back toward the longer trend.

  6. Woud it be possible to blow glass with example Nyiragongo and Halemaumau? These lavas are extremely fluid and often spatters into huge glassy sheets. Ocean entries forms nice glass bubbles sheets called Limou – Pele and Peles hairs

    Nyiragongo and Kilauea are very smooth and runny
    Woud it be a good glass blowing stuff? or is it too much inpurities and too little sillica ?
    Woud Halema’uma’u s fluid lavas make good glass jars and kitchenware?

  7. Hi Folks,

    Do you have good details on Teide Volcano and Canary Hotspot, please?

    Would like to know if partial melting too small for formation of normal Thoelitic basalt in Canary Islands.


    • Tholeiitic basalts are extremely rare in the Canary Islands, as far as I know they are absent in the central volcanoes but can show up rarely in the rejuvenated volcanism, like the Timanfaya eruption of Lanzarote. But rejuvenated volcanism is not directly caused by the hotspot, it happens through crustal flexure and decompression melt created by loading of adjacent volcanic edifices.

    • Hi Philip Evans
      Yes the partial melting is generaly too small under Canaries to form Thoelitic Basalt

      Iceland and Hawaii, and Galapagos are the only oceanic hotspots that produce pure thoeltic melts.

      Iceland and Hawaii produce the purest Thoelitic Basalt
      Because they are the strongest oceanic hotspots

  8. just checking in: we are in pretty much lockdown due to virus and the good news is: the DIL and grandkids are in lockdown with us because they were visiting when everything stopped. 🙂 DIL does all shopping and picking up meds and post office i’m fine, just busy… carry on….. Best!motsfo

  9. What the lockdowns are trying to avoid.

    City of Bergamo, Italy (Pop:120,000). Historical and current monthly recorded deaths from city register. Charts compiled by Bergamo local newspaper. Data for this March obviously not complete. Data up to 26th March.

    Note this is just the city not the entire Bergamo region.

  10. Albert: is Nyiragongos lava cooler than most basalts?
    This is a lava lake bubble burst in daylight from Nyiragongo, and its hardly glowing at all.

    Nyiragongos magmas are formed by the very smallest ammounts of partial melting, and should be cooler than example Hawaii and Iceland where melting rates are much larger.
    Nyiragongos magmas cooler than normal basalts?
    Very dull colour here in daylight

    • Nyiragongo hardly glowing at all in daylight
      This is a Nephelinite – Melinilite magma
      Very very alkaline and sillica poor ( 36% sillicon )

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