Trouble in Paradise: awakening Mauna Loa

An eruption has started at the summit of Mauna Loa. It has been a long wait! The inflation over the past month was notable, though not exceptional, but it was the drip that made the volcanic bucket overflow. We now need to see what happens. Commonly, eruptions migrate down the rift zone, in this case most likely (but not certainly) towards the southwest. But it is also possible that the eruption will be a smaller one which remains in the summit region. We will add information as it becomes available. Below, we republish a post from 2016 on Mauna Loa

Albert

 Radar image of Mauna Loa taken from space shuttle Endeavour in 1994. Colour indicates surface roughness, where red is smooth  (pahoehoe lava) and white is rough (a'a lava).  source: JPL

Radar image of Mauna Loa taken from space shuttle Endeavour in 1994. Colour indicates surface roughness, where red is smooth (pahoehoe lava) and white is rough (a’a lava). source: JPL

Mauna Loa keeps paradise interesting. It has erupted 33 times since 1843, with large eruptions happening on average once every 8 years. Over that time it has covered its slopes with 4 km3 of new lava. But those are just the most recent stirrings. Its older lava flows cover over half of the island of Hawaii. But after the large eruption in 1950, Mauna Loa became remarkably quiet. There have been only two eruptions since, one of which (1975) lasted less than one day and was the second smallest eruption of the 20th century. There was one significant eruption in 1984, but nothing since. But now the largest volcano on Earth is stirring. Inflation shows that magma is accumulating, just south west of the peak. Earthquakes are a daily occurrence and HVO has raised the alert level. There is trouble brewing in paradise.

Mauna Loa is the world’s second tallest volcano on Earth, after Mauna Kea. It started 5 km below the sea, taking perhaps a million years to reach its current height of 4.17 km above sea level. The total height, from base to summit, is therefore over 9 km, more than Mount Everest. To compare, the highest volcano on Earth is Ojos del Salado, on the Chile/Argentina border, which reaches 6,893 m above sea level. Mauna Loa is slightly cheating since the part that is under water benefits from the upward pressure from the water – it floats a bit. I can correct for this, and calculate how high a mountain would be that has the same pressure at its base, without the aid of water: this reduces Mauna Loa by 1800 m, and gives an equivalent height of 7200 m, almost the same as Ojos de Salado. This may not be entirely accidental. There is only so much weight a rock can bear, and both volcanoes will consist of very similar types of rock at their base. Rocks at the bottom, 9 km below the summit, are in danger of being crushed by the weight. On Mars, gravity is three times less and the same weight corresponds to a mountain three times taller – 22.5 km tall. In fact, Olympus Mons stands 22 km above the surrounding plain, almost exactly this number. So it seems this is indeed about the tallest a volcano can get. Mauna Loa and Mauna Kea are almost the same height, differing by only 24 meter. They are running into their limits.

Although it is slightly lower, Mauna Loa is a lot bigger than Mauna Kea. Mauna Loa is a shield volcano: its fast flowing lava has spread far, building a large mountain with a shallow slope. It is much wider at its base than Mauna Kea, has much more volume and therefore much more mass. Mauna Loa, the largest volcano on Earth, is so large, it is very hard to see. You can’t see it above the horizon: it IS the horizon. I remember reading the story of someone in Africa trying to chase an elephant out of their garden at night. In the flash light she failed to see any elephant, just the greyish sky. Only then did she realize the sky was the elephant, so large the eye couldn’t see it. Mauna Loa is this proverbial elephant. The only place from where you can get a good feeling for its tremendous size is from the summit of Mauna Kea (not an easy place to get to either.) From here, at night sometimes you can see the distant, angry eye of Pu’u’O’o, but in the day Mauna Loa dominates the sky line. (Unexpectedly for an astronomical observatory, you can’t see the stars that well from Mauna Kea. It is too high and the eye and the brain are badly affected by the lack of oxygen. You become half blind and too dim to realize.)

Mokuaweoweo crater, with south west rift in the foreground

Mokuaweoweo crater, with south west rift in the foreground

The top of Mauna Loa has its crater, called Mokuaweoweo Caldera. It consists of three partly overlapping craters, of which the central one is the largest. Together they are 6 by 2.5 km in size. The caldera isn’t that old. It formed because of a large flank eruption which emptied the shallow magma reservoir. This was the eruption which formed the Panaewa flow field, which Hilo is build on.

 Lava flows from Mauna Loa. Hilo is front centre, Mauna Kea right. Red and orange are flows since 1832.

Lava flows from Mauna Loa. Hilo is front centre, Mauna Kea right. Red and orange are flows since 1832.

Mauna Loa is a very elongated mountain, much longer in the south west-north east direction. In fact, the name Mauna Loa means ‘long mountain’. The long ridge follows a double rift zone. There is a caldera at the top (showing the mountain used to be a little higher); the rifts extend from the caldera towards the south west and towards the east, running from the south eastern point of Hawaii to (almost) Hilo, a distance of close to 100 km. The south west rift bends by 40 degrees where it reaches an altitude of 2400 m. At this point a number of eruptions have build a satellite shield.

Mauna Loa eruptions tend to begin near the summit, but quickly migrate to the rift zones, down slope. Both rifts can erupt anywhere along their length. Individual rift eruptions can occur along a section as short as tens of meter, to a staggering 20 km (as happened during the large 1950 eruption). Individual eruptions typically last a week, erupt 0.2 km3 of lava and cover 20 km2. The lava moves fast, covering up to 5 km per hour on the steepest slopes, and can reach the sea (on the west and south side, at least), in less than a day.

>Map showing areas covered by `a`a lava flows erupted during the eruption of Mauna Loa between March 24 and April 15, 1984. Source: HVO

Map showing areas covered by `a`a lava flows erupted during the eruption of Mauna Loa between March 24 and April 15, 1984. Source: HVO

The 1984 eruption is a good example. It began three years earlier, with slowly increasing earthquake activity, culminating in an M6.6 event. About 5 months after this, 25 March 1984, the eruption began, after 2 hours of tremors, initially at the summit, but within hours the eruption migrated first to the south west rift zone, changed its mind and moved to the north east rift zone. A few hours later, lava curtains erupted 7 km from the summit, and later that day, the eruption moved to a 2 km section 10 km from the summit. From here lava flows quickly advanced to Hilo. Eventually the flow reached a length of 30 km, coming to within 7 km of Hilo. As the eruption diminished, the active lava stayed closer to the point of eruption. After some tense days, the eruption ended on April 15.

Hawaiian Archipelago: trail of a hot spot

Hawaii is at the end of a long chain of islands and sea mounts. Close to Hawaii are the Windward islands, or Hawaiian archipelago. Further away are the Leeward islands, terminating near Midway. Beyond that, the chain becomes a series of sea mounts, which makes an angle of 120 degrees with the other chain: these are called the Emperor sea mounts (named after Japanese emperors). The mounts get progressively older further from Hawaii, with the oldest one about 80 million years. The chain terminates at the Obruchev Rise, very close to the Aleutian subduction trench, where it meets Kamchatka. There may have been more, older sea mounts, now subducted into oblivion.

chainmap

The Hawaiian chain is the type specimen of a hot spot chain. The hot spot is supposed to have been stationary or near stationary, while the Pacific plate drifted over it. The sharp bend in the chain shows a sudden change of direction of the Pacific plate, about 45 million year ago. Previously, the plate was going north, but now it is moving to the north west. What caused this change? That is not really known. It happened at about the time India collided with Asia, and perhaps this is related although that was quite a distance away. It may also have been caused by the onset of subduction along the Asian plate boundary. After the change of direction, for a few million years no islands were formed.

timeline

Hot spots may come from plumes deep into the mantle, or they can be shallower, affecting mainly the upper mantle. Opinions differ. In the case of Hawaii, seismographs, used to map out the mantle, have detected the hot region to 1500 km depth, perhaps more. That is half the depth to the core-mantle boundary. It seems likely it extends to the bottom of the mantle. It came from the deep. But other data do not agree, and a more recent study has only found a pancake of heat, underneath the crust, not extending into the deep.

In any case, not all the lava it erupts comes from the deep mantle. It seems that over time, Mauna Loa has erupted a decreasing fraction of 3He, and that is a sign that a fraction of recycled crust is being included in the magma. Perhaps as the hot spot is moving away (and Mauna Loa is no longer directly over it, as it was when it began), the magma includes an increasing amount of shallower melt.

How and where did the hot spot get started? Its origins have sadly been lost in the subduction trench. Or perhaps not. Could the hot spot have started at the Obruchev Rise? The Rise is near an old spreading centre, abandoned in the Cretaceous when the centre jumped north. The ridge was at the western edge of the Fallaron plate, which has since largely been subducted underneath America. This puts the hot spot, at its earliest known location, directly underneath this spreading ridge. Much like Iceland! Did the spreading centre start the plume? Or did the plume split the plate? This is solidly in the realm of speculation. But it is interesting to think of tropical Hawaii starting off like Iceland. Perhaps there is hope for Reykjavik.

During its 80 million year history, the eruption rate has been remarkably constant, at about 0.015km3 per year. For comparison, over the past 200 years the eruption rate has been about 0.023km3 per year from Mauna Loa. Kilauea’s eruption rate should be added, which doubles the amount. So the current rate of activity is a bit above average for the hot spot.

Science

Volcanoes provide a very temporary surface and are not the best place to build expensive structures. A good example was the Etna volcano observatory, build too close and unfortunately destroyed by the lava they were trying to observe. They wisely relocated to Catania, for safer viewing. It is surprising to find a scientific institute located near the top of Mauna Loa, and even more surprising that it is not there to study the volcano. The Mauna Loa Observatory studies our air and our Sun – not the shaky ground underneath their feet.

>The Mauna Loa Observatory. In the background is Mauna Kea - Mauna Loa is behind you.

>The Mauna Loa Observatory. In the background is Mauna Kea – Mauna Loa is behind you.

The Observatory is located 5 km north of the summit, 700 meter below it. It is so high up in order to stay away from any pollution (natural or otherwise) coming up from below. The inversion layer in the atmosphere normally keeps that locked up. The air comes in from the sea, again as clean as anywhere on Earth. It is an ideal pace to measure how our air is changing. Since 1956 the amount of CO2 in our atmosphere has been measured. There are several places around the world where this is done, but Mauna Loa has the cleanest record. The buildings, offices and domes are build on stark, black lava fields and even after 50 years, gives an impression of a temporary incursion in an unforgiving land. The total lack of any vegetation is an advantage, as plants affect the local CO2. The famous Keeling curve, showing how rapidly we are changing our atmosphere, is measured here, a monument to our fragility and willingness to take inordinate risks. It fits the environment, but if Mauna Loa were to erupt this direction, the scientists may only have an hour to get away. There is also a solar observatory here. In general, only astronomers put their most expensive instruments on top of active volcanoes. A certain disregard of the world they live in may play a role. There is a massive astronomical observatory on Mauna Kea. Again, their only access road goes over the recent flows from Mauna Loa. One could question the wisdom of building the one escape route where it is most likely to be cut off.

The Keeling curve

The Keeling curve

The mid-life crisis of Mauna Loa

I mentioned that Mauna Loa seems to be losing its hot spot. How do we know? Part of the evidence comes from the changing isotopes, the reducing fraction of 3He compared to 4He. But there is a more direct indication. Mauna Loa has stopped growing.

Mauna Loa’s lava covers half of Hawaii, to the coast and into the sea. The eruptions still often reach the sea, at least on the west side of the island, but they only rarely reach the Hilo area, even though this area is entirely build on Mauna Loa’s lavas. Over the past 100,000 years, the lava flows have not been as vigorous and have not reached as far as previously. Still, Hilo should not be complacent. In 1880 lava reached with 2 km of Hilo Bay.

How far lava can flow depends on the cooling rate. The flow stops where the lava solidifies. The higher the flow rate, the slower the cooling (large bodies stay warm for longer), and the further the lava flows reach. This process is very clear in Kilauea. When the eruption rates go up, the lava flows extend, as they did last year. When they decline, lava stays closer to the point of eruption, mostly less than 5 km this year. Holuhraun did the same thing: when the flow began to diminish, the flow field stopped expanding. Lava from Mauna Loa now rarely reaches Hilo Bay, perhaps only once per 4000 year. It mostly stops 5-10 km from Hilo. One flow did cover the entire urban area and the bay, perhaps 1000 year ago, but this one erupted from a vent very close to Hilo to begin with. Most of the lava now flows closer to the rift, and less lava reaches the sea. This makes the mountain grow steeper: it is beginning to enter its post-shield phase. This may be related to the growth of Kilauea, competing with it for lava resources.

The weight of the mountain pushes the crust below down. The whole island subsides, at around 2 mm per year. So far lava deposition has just about kept up with this, but it may not for much longer. The baton is being passed and Mauna Loa will sink.

The 30-year silence of Mauna Loa has coincided with the continuing eruption of Kileauea at Pu’u’O’o. This eruption started in 1984 and is still going. But eruption rates have slowly declined. The central crater of Kilauea shows inflation and this may be due to an ebbing flow through to Pu’u o’o. It is argued that Mauna Loa and Kilauea are separate volcanoes, from two different hotspot tracks, Kilauea connecting to Mauna Kea. This seems less likely, and although the feed systems are not identical, they are not independent either – they are too close together. The question will be settled soon: if they are independent, a Mauna Loa eruption would not affect Kilauea. If there is connection between them, you would see Kilauea changing when Mauna Loa erupts. Will in the future Kilauea take over and rival Mauna Loa in size? Perhaps they really are too close. There is another candidate waiting out at sea, which is more likely to become the next giant.

Towards eruption?

magma_chamber

After 20 years, activity underneath Mauna Loa resumed in 2004, with a series of deep earthquakes. The mountain began to inflate at the same time. Things calmed down again, but in 2014 earthquakes moved to shallower levels, and inflation increased. Magma is now accumulating at 3-5 km depth, below the south west rift. Activity is continuing at an elevated but non-critical level: it has all the appearance of building up to an eruption, but it does not appear to be imminent. Will it be a year, five years, longer? After the previous burst, in 2004, nothing happened for a decade. The current episode could equally go off the boiler. But the magma is now shallower, and the inflation more focussed. This is beginning to look as if it is closer to deciding to erupt.

Inflation and earthqauke activity at Mauna Loa. Source: HVO

Inflation and earthquake activity at Mauna Loa. Source: HVO

An eruption is likely to start within hours of strong tremors. Initially it will be close to or at the summit, before rapidly migrating. As the current inflation is a little south west, the most likely migration is in this direction. The lava could flow either side of the ridge. For a normal-size eruption, Highway 11 will be cut within one or two days, possibly at several locations if the eruption is large, and lava will flow into the ocean shortly after. Judging from the time line of the various flows since 1843, Kealakekua Bay would seem next but this is guess work – Mauna Loa does not work like that. As the magma chamber empties, the risk of larger, possibly damaging earthquakes increases. The south side of the mountain is prone to slipping and the risk of this increases when the pressure changes. Conversely, earthquakes can also affect internal magma flows and an earthquake can hasten or stop an imminent eruption. The double 1868 earthquake (M7.1, M7.9) disrupted the magma supply for decades.

Purely based on the past record, there is a 50% chance of an eruption within 8 years. I would expect something within a decade, most likely from the south west rift zone. When it happens, it would be advisable to run away, and not, as Hawaiians normally do, run towards the eruption to get a better view. Mauna Loa is not like Kilauea. It is fast and furious, best viewed from a large distance. Paradise can wait.

Background reading

Hawaiian Volcano Observatory; Much of the material and several figures in this post came from them

Hawaii’s island chain, with exam questions at the end! Source of some of the figures and material used in this post

207 thoughts on “Trouble in Paradise: awakening Mauna Loa

  1. The latest from Big Island Video News, with video and commentary by USGS expert:

    • Looks alot like Holuhraun now
      Just like Baugur, it may end up forming a similar bathtub

    • fissure looks like doom in night.. like thermite reaction… loves it.. and probaly as large as Holuhraun Baugur as well in scale of output

  2. https://www.usgs.gov/volcanoes/mauna-loa/monitoring-data shows a change on the MOK electronic tiltmeter. Can we safely assume that there was a permanent change in the tilt due to intruded magma, or that the instrument is just settling back down to the old values, but offset a bit?

    Curious as to what this spike and setting is indicating?

    • There are a lot of instruments in the net–not just tiltmeters, but GPS, seismo, gas sampling, that seem to not register much of anything, and then there is an anomaly, there’s no context. I know that explaining to armchair enthusiasts like us isn’t high on USGS’ list of priorities, but aren’t they using these instruments, too?

  3. Mauna Loa eruption overflight footage by Andrew Hara, 11.29.22 at 6:30am (Hawai‘i PODD)

    • Try and get it right this time 🙂

      Mauna Loa eruption overflight footage by Andrew Hara, 11.29.22 at 6:30am (Hawai‘i PODD)

      • Seems to be going along the northwest side of the 1899 and 1935 flows. If it keeps up for a long time it will flow into the saddle near Pu’u Huluhulu. But that is a while off, the flow reached the flat ground now so will move much slower I expect.

        The wild card is if a lower vent opens. This could be on the rift zone as in 1984 but lava could also erupt out of the north flank, which happened in 1843 and 1935, and almost happened in 1855. There are a few recent prehistoric examples too. This would probably be as an entirely effusive vent, the existing fountaining vent would stop and become a glowing gas vent while lava flows silently from the lowest spot. If this happens all bets are off, and it would be unpredictable as these vents probably form from sills instead of dikes so are aseismic. Such a vent would also probably make a tube so can flow further.

    • That’s actually a great video and worth watching but obviously not the right URL 🙂

      • And now I can’t even reply to the right comment. Need sleep 🙂

    • If it is what looks like a satellite view, that is from Hawaii Tracker on FB. I think they got it from USGS

      • Wow pyrocumulus developing over the Warm surfaces

        I can just imagine what huge lava supercells that must have formed over CAMP vents or oven Siberian Traps perhaps even hypercanes over these

  4. https://www.youtube.com/watch?v=l1737luewGA

    Live by ApauHawaiiTours again, saddle road.

    Can see how far the lava has flowed now too, to the bottom of the mountain in this area. This really is the best spot the lava could have gone really, no dangerous SWRZ flows, and it would take an enormous eruption and a year at least for the lava to reach either Hilo or the north Kona coast. So basically this is a tourist eruption just a way bigger and more impressive one 🙂

    • You’ve been pretty fantastic with your predictions lately Chad. Wanna take a stab at a total maximum erupted volume for this event? You can give a range, precision not expected =P.

      • I mean in totality, when all is said and done and the eruption ends.

        What’s your estimate?

        • SO2 emissions given have been 250,000 tons/day, which is enormous. This is about the same as what was measured for the 2018 eruption for example, although that did sustain that rate for over 2 months so this is still far away by comparison. This seems to be pretty normal value for larger Mauna Loa eruptions though, Kilauea has the long term volume but Mauna Loa has bigger single eruptions, as expected when there are 40 year gaps between 🙂
          There is a very rough guide that the SO2 number is about 1000x the effusion rate in m3/s. This doesnt entirely work for open volcanoes like Kilauea (lava lake was 4 m3/s filling and 1500-3000 t/day SO2) but for fresh magma that has not degassed like we see from Mauna Loa that is not really a problem. There is probably a more accurate SO2 ratio but this works for now.

          These values are way higher than any number you will see before 2018 because up to then the sensors used were unknowingly being completely saturated, giving readings that were at least an order of magnitude too small, and this was apparently only discovered in 2018 at Kilauea… So basically whatever number you see on an old eruption before than, make it at least 10x bigger and that is probably more accurate… Laki was probably 1 million m3/day, the opening of many Mauna Loa eruptions (including this one) are probably much higher than that even, just not sustained for very long.

          So, at 250 m3/s estimated, and now 3 days, the volume could be 65 million m3. I think this is too high though, the lava has not flowed that far compared to what it did in the same time interval in 1984. But I would feel confident saying this eruption is at least significantly bigger than 1975, which was 30 million m3 erupted. The lowest vents are at 11,100 ft / 3360 m, and the total length of the dike is about 20 km, at 3 km deep and 2 m wide that is 120 million m3 in the dike. If the eruption is as big as my above measurement than that brings the total to 185 million m3.

          HVO has said the intruded magma now exceeds that in 1984. I dont know if they mean the total pressure or the amount of erupted lava, because that is either 400 million m3 or 220 million m3… If it is the second number than this eruption might only last a few more days assuming my number is anything close.

          But if it is the larger number, and the vents dont move, well then this could end up being pretty huge, although I am still very doubtful it is ever going to go anywhere near anything important where it is now.

          So 65 million m3 erupted, and between 3 and 10 days longer at current rate. But I also think it will evolve, so this is likely to date itself pretty fast

          🙂

    • I think it has taken out the observatory road. So I’ll disagree with you that this was the best spot!

  5. Back in 1980 I vacationed on Hawai’i and drove the saddle road though the car’s insurance specifically forbade it. Now I see why. While drving through the a’a fields I was joined by a group of battle tanks. I didn’t know they drove that fast! Fortunately they waved in a friendly manner as they passed on both sides.

  6. Just found a new geologist posting on YouTube. This episode is in Iceland, found a dike exposed on the surface that bisects some bedded tuffs and the erupted lava above the tuff. Iceland, Dike, basalt, geology that you can see, has it all.

    https://www.youtube.com/watch?v=1vCURNSZoQ8

    Mac

    • Pretty impressive to see that dike, thanks for posting it. The author, Shawn Willsey, has written two books so far, one about Idaho and another about Southern Iceland.

      • Oh no, reading mistake. Southern Idaho. Could be quite interesting thoung, including Snake River Canyon with Ctaters of the Moon.
        Where are my glasses?

      • The flow shouldn’t go much beyond the saddle road because the land start to rise towards Mauna Kea. If it gets there, it will pool near the road and start to flow along the road. Or on it.

    • Its very fluid and Nyiragongo like close to the vent for soure

      But further down it cools without an insulating tube ( eruption rates too fast )

      The Aa lava is supprisingly viscous at the flow front, althrough probaly Wont get more viscous than that, because the thicker it is the more heat it will retain

      • Its not really that viscous, less than 10 m thick even flowing so far and on a gentle slope

      • The lava at the source seems rather rough in the flow channels close to the vent. Many previous Mauna Loa flows been alot smoother

        Perhaps because of cooling in the dyke or a crystal rich composition

        Check details here
        https://m.facebook.com/story.php?story_fbid=pfbid0W6MXdA2KfLUAanDrYj7yqNqRsP1sKfNuSkNynnBGeBmSiXoZXTP95RgBoMAjzLXjl&id=1409735998

        https://m.facebook.com/story.php?story_fbid=pfbid0W6MXdA2KfLUAanDrYj7yqNqRsP1sKfNuSkNynnBGeBmSiXoZXTP95RgBoMAjzLXjl&id=1409735998

          • That would have been nice. I just get ‘Sorry, this content isn’t available right now’

          • so do I now.
            I often get a starfield when very large files are referenced which later appear. I have attributed that to the volcanocafe server taking a long time to download it into cache.

        • High eruption rate and steep slopes, it will be hard to form pahoehoe as much in this area. But I have not really seen any evidence that the lava is sticky near the vents, it forms a lot of smooth pahoehoe overflows. There is also a distant view of a lava wave that formed in the channel where lava had to flow around an obstruction, so the flow as a whole unit seems to be very fluid just with an a’a surface.

      • There is channels and standing waves Althrough the channels dont have a smooth paintlike skinn on them like They have on most Mauna Loa channels

        Too fast To form pahoehoe But perhaps less fluid than normal

        Recheck some of that persons Photos .. and zoom in on some of the smaller features

        Leilani was much smoother overflows and near vent spillovers.. I have provided Hector with edivence over FB

        • I think maybe most pictures of 1984 were more than 3 days into the eruption, fissure 8 had rough surface too until the lava had been flowing through the area for at least this long and some places a lot longer. If this flow stays for another few days you will see the pahoehoe channels 🙂

      • Well Mauna Loa eruptions tend to form sheet pahoehoe close to the fissures on the opening day

        The sheets we had now have been of an Aa quality kind of a little close to the vents. Overall this lava have a very similar texture quality to Holuhraun.. that was very rich in small crystals yet hot and very fluid. The apparence of the lava is also similar to Meradalir eruption 2022 just that this is a much larger and faster eruption

        But yes these fast eruptions always feed Aa

        • There is sheet pahoehoe in Mokuaweoweo from this eruption 🙂

      • Yes Thats right … perhaps because that magma was fresher from source .. this current one is older stuff thats pushed out a volcano as huge as Mauna Loa will have plenty of magma stoorage

  7. https://www.youtube.com/watch?v=wV-hUCANG34

    Livestream for today 🙂

    I also made a real map of the flows based on the one USGS made today. The active flow is about 15 km long, fissure 3 that is the major vent is 7 km down the rift from the edge of Mokuaweoweo, and the furthest east fissure is 8.5 km down the rift. The SWRZ is a bit of a mystery, so I made my own map based entirely off of the pictures from day 1 taken from Kona. Most likely very wrong and a new map will resolve this soon but until then I will keep it 🙂

    And the fissures:

    The main vent is 3350m above sea level, the lowest vent is 3365m above sea level but much less active. The floor of Mokuaweoweo where the eruption started is almost exactly 4000m above sea level, and the southern end of the southwest fissure is at about 3660m. The main 1984 vent was 2940m above sea level with the lowest vent at 2700m. The lowest vent in 1975 was at 3700m on the NERZ, and at basically exactly the same location as some of this eruptions fissures. So this eruption is basically half way inbetween these two, although it is behaving much morel ike 1984 given it has a main vent and has lasted for longer than a day.
    There was an inSAR too today and that showed the eastmost vent is also at the end of the dike, and the dike is now no longer extending so this is probably it as far as new fissures unless a north flank effusive vent opens like in 1935, an unlikely case.

    • The main flow follows an older flow quite closely. This will bring it to the saddle road just west of the Mauna kea access road, stall there, and flow either west or east along this road. If it gets that far – 50/50 chance, I think.

      • It is flowing between the 1899 and 1843 flows, abd further down between the 1843 and 1935 flows. So it will basically go right into the flattest bit of the saddle, supposedly it will go towards Hilo eventually. But it is pretty clear from the map that the only flows to go into the saddle and escape again are pahoehoe flows, the a’a flows stall. I dont know if we should expect this eruption to become long lived to create pahoehoe and tubes.

        Although, I do wonder if the recent slow activity at Kilauea was in part related to Mauna Loa, changes in pressure. It could be coincidental but then this is a pretty big coincidence…

    • The eruption continues and seems very stable and very vigorous, woud not supprise If it becomes larger than 1984.

      Yes perhaps given enough time the channels coud perhaps crust over and become something like at Theistareykjarbungas tube system thats very marsian in look. High eruption rates in other bodies in the solar system have formed huge tube systems as well.

      If I Remebers correct 1984s channels barely just started the crust over process But the eruption ended

      But the eruption rates coud also slow down and form a ”normal” pahoehoe tube feed field

  8. 1984 was a very big eruption, by volume there are several that are larger but most of those became so by lasting for a long time, where 1984 was only a few weeks. Only 1950 was absolutely larger, while still being a fast eruption. 1868 eruption was about the same size though faster.

    Eruptions like you describe, forming massive tubes and a’a fields around a cone, those do happen at Mauna Loa but none have happened historically. The last was about 500 years ago on the SWRZ, flowing into Kipahoehoe bay. A much bigger eruption like this was at Pu’u O Keokeo, above Ocean View. This eruption is probably one of the biggest basaltic eruptions on the planet in the past few millennia, covering several hundred km2 of the island in a’a and pahoehoe, and ultimately ended in a lava flood and probably caldera collapse. These eruptions are not as fast as eruptions that create calderas, but are way higher than the supply rate from the mantle. My personal theory is they are the collapse of a magma chamber that is too deep to form a ring fault connecting to the surface, so the collapse is through slower elastic deformation rather than rapid collapse directly under gravity. This is probably what happened at La Palma. It is also what I think happened at Laki. The tubes form simply because the eruption lasts long enough for the channels to roof over, which would imply long durations if months to years but very high eruption rates of several tens to even hundreds of m3/s average effusion.

    I dont see that happening now though mainly for one reason, the eruption is too high up. All the eruptions if this type on Mauna Loa have been at least 1 km below the summit and larger are lower down – Pu’u O Keokeo is 2 km below. Kilauea has no eruptions like this on land, it is only 1 km tall, there might be examples on the Puna Ridge.

  9. A bit ot:

    I had seen an article about a new method to identify a piece of metal that might, after all, belong to Amelia Earheart’s plane, lost like her and her navigator, somwhere between Howland Island, Baker Island and Nikumaroro in the south.

    Studying the Pacific Ocean as usual which is always mysterious and entertaining I found the anmazing row of submarine volcanoes and next to them volcanic fields which are all contributed to the Cretacious.

    What might have gone on there? I thought and then suspected the birth of the Pacific Plate and a subduction zone with the Phoenix Plate diving under the Pacific Plate.

    In the following paper two pics that seem to prove this right.
    https://www.researchgate.net/figure/Relative-motions-of-the-Phoenix-Pacific-Farallon-and-Izanagi-plates-in-the-hotspot_fig1_228488729

    The research going on there is also amazing:
    https://oceanexplorer.noaa.gov/okeanos/explorations/ex1703/background/biogeography/welcome.html

  10. Info
    PMC2582290 In situ carbonation of peridotite for CO2 storage Peter B. Kelemen1 and Jürg Matter

    The rate of natural carbonation of tectonically exposed mantle peridotite during weathering and low-temperature alteration can be enhanced to develop a significant sink for atmospheric CO2. Natural carbonation of peridotite in the Samail ophiolite, an uplifted slice of oceanic crust and upper mantle in the Sultanate of Oman, is surprisingly rapid. Carbonate veins in mantle peridotite in Oman have an average 14C age of ≈26,000 years, and are not 30–95 million years old as previously believed. These data and reconnaissance mapping show that ≈104 to 105 tons per year of atmospheric CO2 are converted to solid carbonate minerals via peridotite weathering in Oman. Peridotite carbonation can be accelerated via drilling, hydraulic fracture, input of purified CO2 at elevated pressure, and, in particular, increased temperature at depth. After an initial heating step, CO2 pumped at 25 or 30 °C can be heated by exothermic carbonation reactions that sustain high temperature and rapid reaction rates at depth with little expenditure of energy. In situ carbonation of peridotite could consume >1 billion tons of CO2 per year in Oman alone, affording a low-cost, safe, and permanent method to capture and store atmospheric CO2.

  11. Semeru has erupted again, exactly one year after the previous eruption. Early reports sound very similar to last year. Last time it erupted for several weeks with some pyroclastic flows out to a few kilometers.

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