Grand Canyon Volcanoes

/ 28/08/2022

Republished from https://roseannechambers.com, with kind permission by the author. It is a blog we happily recommend to our readers!

In the recent geologic history of the Grand Canyon, volcanoes erupted in the Colorado River channel and on the rim, pouring lava over the canyon walls. Hot lava often flowed down the river channel for tens of miles; other times, it dammed the river, impounding water behind dams that eventually breached, sometimes releasing catastrophic floods. When most of us think about the impressive geology of the Grand Canyon, our focus is on the ancient rocks. Most of these cover the immense range of time from hundreds of millions to as much as about 1.8 billion years old. Within the past one million years, however, volcanoes have created striking displays of rocks that are interesting from both geologic and aesthetic perspectives.

Recently, I had the good fortune of joining a group on a river rafting trip that extended over the entire 280-mile (450 km) length of the Grand Canyon. As a geologist with a strong interest in stratigraphy, a trip highlight for me was the exceptional narration by geologist Wayne Ranney. Wayne’s decades of experience studying the geology and exploring the Canyon have given him a deep level of knowledge that is unrivaled; it was a great pleasure to travel with him.

Giant flows of basaltic lava cascade over the rocks along Grand Canyon walls—and what we can see today are only remnants of the enormous volume of lava that poured into the Colorado River between about 850,000 and 80,000 years ago. Some of these lava flows extend as far as 84 miles (135 km) downriver. The lava flows contribute to many of the rapids that make the river an exciting, world-class place for boaters. The dramatic and enormous rapids in the Lava Falls area —considered among the largest and most difficult of the Grand Canyon rapids—result from rocks emplaced by at least ten voluminous lava flows between about 700,000 to 400,000 years ago, plus a few isolated smaller flows around 250,000 to 100,000 years ago.

Between the narrow canyon walls, lava dams formed repeatedly, impounding the river water and then eventually breaking down. Based on detailed age dates, geochemical analysis, and geologic field mapping, researchers suggest 17 separate lava flows or series of flows occurred. Most, if not all, produced lava dams that temporarily halted the flow of the Colorado River. Dam thicknesses varied from 115 feet (35 m) to at least 1,080 feet (330 m). Some dams likely stayed intact for tens or hundreds of years; others probably lasted for millennia.

Vulcan’s Throne (distinct cone on the right center) and dark lava flows draped over the colorful sedimentary rocks on the Grand Canyon rim (the black zone in lower center is a shadow). 2008 (Wikipedia)

Volcanic plumbing is visible deep in the Grand Canyon, including plugs, sills and dikes that originated underground and are now exposed by erosion . One large plug, named Vulcan’s Anvil, is prominently located in the middle of the river. Lava from the eruption that created this feature, called the Upper Black Ledge flow, was about 230 feet (70 m) thick at Vulcan’s Anvil and flowed downstream for at least 47 miles (76 km).

While floating down the river, the array of patterns in the basaltic lava was fascinating. Columns of rock arranged into huge fan shapes are especially impressive. Colorado River water interacted with hot lava as it cooled, creating these notable forms. Two-tiered cooling structures, as shown in the photo below, are common. Two textures developed: the lower colonnade has straight, well-formed vertical columns, and the upper has smaller and more randomly oriented ones. A combination of water-steam interaction and flowing river water that overtopped the hot lava created these different cooling structures.

Note: columnar jointing (cracking or fracturing) in a regular array of polygonal prisms or columns develops as the hot lava cools and contracts. It is characteristic of many volcanic rocks, including Devils Postpile in the Sierra Nevada of California, Devils Tower in Wyoming, and the Giant’s Causeway on the coast of Northern Ireland (check out the great photos in the Wikipedia entries for these features).


The basalt flows found in the Grand Canyon originated primarily from the Uinkaret volcanic field, located in northwestern Arizona to the north of western Grand Canyon. This field is still considered to be active and capable of future volcanic eruptions. The most recent lava flow from this field, named Little Spring, probably erupted around 1050 to 1200 CE, based on age dated Native American pottery shards found welded into the lava. The nearby San Francisco volcanic field is also active. The most recent eruption in this field occurred at Sunset Crater, dated at about 1084 CE. When will the next eruptions in the Uinkaret and San Francisco volcanic fields happen? No one knows – we can only guess.

The 1869 expedition down the Grand Canyon, organized by the brave explorer John Wesley Powell, has the following report entry dated August 25, 1869:

Great quantities of lava are seen on either side; and then we come to an abrupt cataract. Just over the fall a cinder cone, or extinct volcano, stands on the very brink of the canyon. What a conflict of water and fire there must have been here! Just imagine a river of molten rock running down into a river of melted snow. What a seething and boiling of the waters; what clouds of steam rolled into the heavens!

This would definitely be an impressive sight. And eventually, it could happen again. We live on an active planet!

Vulcan’s Throne and Lava Falls rapids — black lava is on plateau and draped over horizontally bedded sedimentary rocks along canyon walls; Colorado River is visible in lower right corner. USGS 1950 (Wikipedia)

SOURCES
  1. Crow, R.S., Karlstrom, K.E., McIntosh, W., Peters, L., Crossey, L. and Eyster, A., 2015, A new model for Quaternary lava dams in Grand Canyon based on 40Ar/39Ar dating, basalt geochemistry, and field mapping. Geosphere, 11(5), pp.1305-1342.
  2. Powell Report quote from Belknap, B., and L. Belknap Evans, 2006, Grand Canyon River Guide, Westwater Books, Evergreen, Colorado, 18th printing of revised edition (2006).
  3. Ranney, Wayne, 2012, Carving Grand Canyon: Evidence, Theories, and Mystery (Second edition), Grand Canyon Association
  4. Valentine, G.A., Ort, M.H. and Cortés, J.A., 2021. Quaternary basaltic volcanic fields of the American Southwest. Geosphere, 17(6), pp.2144-2171.
  5. Photo of Vulcan’s Throne and Lava Falls, where the Uinkaret Volcanic Field pours into the Grand Canyon, by Doc Searles from Santa Barbara, California, 2008. https://commons.wikimedia.org/wiki/File:Lava_Falls,_where_the_Uinkaret_Volcanic_Field_pours_into_the_Grand_Canyon.jpg
  6. Photo of Vulcan’s Throne and Lava Falls, USGS image by J. R. Balsley, 1950. https://commons.wikimedia.org/wiki/File:Vulcans_Throne_and_Lava_Falls_in_Grand_Canyon_NP.jpg

Other photos by R. Chambers, May 2022.

Roseanne Chambers, August 2022 (original post June 16, 2022)

Insights on geology and human culture – check out my blog at https://roseannechambers.com/

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99 thoughts on “Grand Canyon Volcanoes”

  1. It is interesting that last year a special NASA research plane flew over these fields, checking their current state.

    • Good to know – it will be interesting to learn about what was found.

  3. Lava flowing into Valles Marineris.. I wonder If that have happened as well on Mars

  4. This is the kind of post that makes me want to go there and see it for myself! Lovely

    • Thanks, Albert! I’d love to go back on another river trip someday to have more time to watch the geology roll by. (The current is strong, with lots of rapids, along the stretch with Quaternary lava!) The views of dikes in the walls of the canyon and the middle of the river were especially fascinating.

  5. I remember being fascinated the first time I found out part of the Grand Canyon goes through a volcanic field that is still active, and even within only the last 1000 years. What I an tell is that the Canyon itself has not had lava in it since the Pleistocene though, activity moved north a bit away from it, but who knows we might see the lava falls again one day 🙂

    Its only a matter of time before we see another monogenetic cone form on the North American continent, many places under 1000 years old, and Jorullo and Paricutin in recent time, its bound to happen.

      • Maybe safest bet is Craters of the Moon, it has a long history and consistent cycle, as well as a much more powerful source than most of these other places. Theres a very high chance of it going in the next 1000 years, ant not small chance in this century. Its a bit like Reykjanes except eruptions there are much bigger.

        But statistically it is likely something will happen this century, more likely than any of the Cascades stratovolcanoes having a major eruption in the next 100 years.

        • About the Craters of the The Moon…I think I’ve read somewhere that it could erupt within the next 200-300 years. The eruption styles there aren’t much different from the recent ones we’ve seen on the Reykjanes ridge. So in other words, what we’ve been seeing in Geldingadalur and Meradalur will likely resemble what we can expect at Craters of the Moon.

          • Actually the eruptions at Craters of the Moon are much bigger, there are a’a flows 30 km long that flowed over flat ground, and covering an area twice as big as Holuhraun. It is true the biggest eruptions are pahoehoe shields but they begin with a real lava flood. The initial fissure eruptions are also probably extremely fast, it is not like Holuhraun or Laki that had large chambers to drain for months, it is more like Krafla which erupted most of all of its eruptions within a few hours of the onset. It is fed by overpressure of a magma chamber, not draining under gravity. It is the same mechanism that drives Hekla, and the intense summit eruptions of the Galapagos and Hawaiian volcanoes.

            So if you want to see 1 km3 of lava flood out in a day and then building a shield for a decade afterwards 🙂

          • Yes, Craters of the Moon is a little different from other basaltic volcanoes of the Snake River Plain. It is a polygenetic volcano with large violent fissure eruptions and mildly evolved magmas. Craters of the Moon is also alkaline as opposed to the other basaltic volcanoes in the Snake River Plain which are subalkaline and erupt primitive tholeiite basalt in slow, long-lived eruptions. I think there is on average one eruption every 1000 years or so in the Snake River Plain, usually from Craters of the Moon.

          • Well then it being 2000 years since the last eruption I think we are due another one soon 🙂

            I never really realised how huge Crwaters of the Moon actually is until recently. I had always assumed it to be another one of the many fields of voclanoes that migth erupt once in many millennia and no-one really knows if it is still actually active anymore…
            Instead it is an Icelandic fissure volcano of a calibre to rival iceland itself, the last eruption began with a 12 km long curtain of fire that was as much as 300 meters high, and sent floods of a’a as far away as 15 km. One of the vents became a 500 meter tall fire fountain. It also looks like it had its own fissure 17 too, a more viscous lava near the north end of the dissure, close to the tall fountain vent.
            Then to top it off the eruption kept going for decades and covered over 300 km2 of the surrounding areas in pahoehoe. The Blue Dragon eruption probably reached over 5 km3, with over 1 km3 in the initial fissure. It also looks like the Wapi shield is from the same eruption, at the other end of a 70 km long dike. Wapi is 6 km3 by itself, and also lasted decades and began with a fast fissure that was later entirely buried…

            It also looks like there were significantly bigger eruptions in some of the prior Holocene events too. The whole system is only 15,000 years old, who knows what it will look like at maturity…

          • Reminds slightly of Hekla and Dubbi. In the the fast fissure style consisting mainly of mafic and intermediate lavas.

          • I do wonder if maybe Craters of the Moon might be like a smaller scale equivalent of the Columbia basalts. At least its earlier stage creating the Steens basalts. The LIP was sort of a hybrid of a back arc rift and a plume, as well as what seems to be the decompression of a continental margin after tens of millions of years of compression and mountain building. Today the area still spreads apart slowly hence the Basin and Range, and the Snake River Plain is in the wake of a powerful plume that may have been a significabt factor in creating the B&R in the first place. Its a tear in the crust that is kept open. Maybe because it is under thicker continental crust the mantle stays hot much longer after the plume has passed than it would under oceanic crust, not enough to sustain the massive calderas that were once there but it is still able to erupt frequently.

            A full blown LIP again is a big stretch, but I wouldnt be surprised if Craters of the Moon eventually evolves into something huge, to rival Bardarbunga in total extent and scale of eruptions. Potentially even much bigger eruptions if it is still stuck to erupting at millennia intervals like now.

          • Here is a map of the last sequence. It is not confirmed that the eruptiosn actually all happened together, but given what we know of similar sequences elsewhere and the radiocarbon dates having an overlap at about 2100 ybp, 100 BCE, it seems very likely that all of the lava was erupted in a single event that lasted several decades.

            Purple: Serrata stage, violent lava effusion from a fissure system 12 km in length. Flows were very fluid and reached great distances from the vents, up to 15 km. Mostly trachyandesite by volume. Slightly more viscous lava forms a pancake dome at the north end of the fissure.
            Volume likely approaching 1 km3, with rapid eruption and tall fountains.

            Cyan: Blue Dragon stage, voluminous effusion of basaltic pahoehoe, forming a flow field that is over 300 km2 in area. Effusion was not always constant, with numerous cones and drained lava lakes close to the vents showing periods of faster eruption. Volume in excess of 3 km3, possibly as much as 9 km3.

            Blue: Wapi stage, construction of the Wapi shield volcano 70 km south along a rift from the previous volcanism. began with brief intense fissure eruptions of degassed lava, vollowed by prologed shield building. Volume estimated at 6 km3.

            This eruption produced at least 10 km3 of lava, over probably a couple of decades. Using the highest numbers it gets to 16 km3, which is one of the biggest effusive eruptions on the planet in the Holocene. It also looks like the much older Grassy cone eruption was bigger still, and was dominated by its fissure stage. Mostly buried apart from the cone itself, it was probably a curtain of fire that was the length of the whole volcano, it is the source of most of the visible a’a that goes as far away as 33 km from the fissure swarm. My estimate is this erupted somewhere around 6 km3 of lava that was probably erupted very fast within maybe only a metter of weeks. There was also a pahoehoe stage, and an outcrop on the north side of the lava field suggests a large area of the a’a flow is buried under the Blue Dragon flow in addition to the exposed area. This was probably an eruption just as big as Laki.

            Really this place is a monster.

          • I don’t think a LIP, but maybe a large silicic caldera system could come out of Craters of the Moon. That is the expected evolution of Dubbi and Hekla after all. And Craters of the Moon does slightly resemble those two, although without the felsic magmas that produce energetic plinian/subplinian eruptions.

          • What I can tell is the CRB was also like that, the lava floods happened from the Chief Koseph dike swarm which goes north about 700 km from the McDermitt volcanic field. That field is usially considered the first of the Yellowstone chain, and apparently most maps dont actually include all the calderas present in it. The calderas got bigger, VEI 8 standard, as soon as the peak of the CRB passed although the Chief Joseph swarm stayed active until as late as 6 MYA.

        • I’d love to see a new eruption in the Raton-Clayton Volcanic Field, it’s been active for over 5 million of years, but with long gaps. The most likely scenario would be another monogenetic cinder cone like Capulin Volcano.

      • Given that I live close to Dotsero, I’m okay with it not erupting in my life time.

    • North America is also home to most Mexican shields of the world. Monogenetic shield volcanoes of generally basaltic-andesite or andesite composition that can reach volumes of over 10 km3 and can tower to heights of several hundred meters, built in a matter of years or decades. Like Belknap, or El Metate. Mexican shields are found all across the High Cascades and the Trans-Mexican Belt, and are very rare elsewhere in the world.

      • There is a lot of monogenetic volcanism in the US southwest, along the Rio Grande and the Colorado. There is a young looking, very large lava flow in New Mexico north of White Sands Missile Range which seems holocene. It is several km3 in volume. Older volcanic lava cones are along the Rio Grande valley south of Albuquerque – but I did not see any inside it. The cones of Flagstaff look rather different, very tuffy. There is a large and growing magma chamber underneath Socorro without an obvious exit route.

        • The fact that the entire area is hugely elevated suggests quite a big melt over a huge area underlies the south western USA. Presumably remnants of a melted subduction. It should be very much more volcanic IMHO.

          • “SLS will be pulling 39.1 meganewtons (8.8 million pounds) of thrust off the pad. That’s close to 15% more than the Saturn V rockets that sent the Apollo astronauts on their way to the Moon in the 1960s and 70s.”
            That’s 4000 tons weight worth for a rocket weighing er, um, dunno. Nobody seems to quote the launch weight.
            Odd

          • 8.8 million pounds (US units) is the launch weight. The pay load is less than 1% of that

          • I never thought SLS would fly, I still think it should not be used but at this point the sunken cost falacy sort of falls over and it really is sort of a necessity that the thing flies, its either a waste of money that looks impressive or it is just a waste of money…

            SLS is though, the most powerful machine that we have ever created that exists in its complete form. And Starship is even bigger and close to completion too, the wait is over. This launch marks the point we finally get to imagine the future the Apollo era promised. It is way too late but better late than not at all.

        • There is also the McCartys flow of Zuni Bandera, a quite sizable long-lived event, ~3000 yrs old.

          The youngest lava flow eruption in the area was the 660 year old Ice Springs lava flow, which was an intense eruption with powerful fountaining and a rapidly emplaced lava flow. Probably comes from a magma chamber that has erupted some nearby rhyolite in Fumarole Butte volcano.

          And of course 1000 year old Sunset Crater is worth mention. A VEI-5 eruption.

        • The Colorado Plateau even has its own Urach. The volcanic field of Hopi Buttes is made up of maars and diatremes of rare ultrapotassic, strongly silica-undersaturated foidite chemistry. However it is thought to be extinct.

  6. Thanks for this article! We flew by helicopter from Las Vegas out to the Grand Canyon and I remember being amazed at the colours in the desert. Volcanic black cones mixed with ochres and greens, and the usual colours of sedimentary rocks. It’s a fascinating landscape.

    • Thank you, Clive! I think it is a fascinating region also, and fortunately I’ve been able to explore some of the remote corners. There are lots more that I hope to see!

  8. Speaking of Taupo, has anyone seen the latest activity over the past week? It looks elevated to say the least.

  10. Roseanne, thank you for the very nice and informative article.

    As you mentioned, the flows into the Grand Canyon that are described are part of the Uinkaret Volcano Field, one of three volcanic fields touching Arizona. Also mentioned is the San Francisco Volcanic Field, threatening Flagstaff. With its high peak and surrounding cinder cones, it’s very imposing.

    The third volcanic field is mostly in Mexico. Pincante. Containing over 600 cinder cones and many immense craters, it is spectacularly preserved in the desert, surrounded by mostly sand dunes. I read that it was a very visible geological feature visible with the naked eye from space. It’s fun to virtually visit there on Google Earth. The last eruption was about a thousand years ago.

    There is speculation that the three volcanic fields are associated with a hot spot. Hard to imagine. FarmerOz’s idea that the Uinkaret activity is associated with a wide uplift wouldn’t work here because it is near sea level. It’s near to the Pacific Plate boundary.

    Not sure anyone would notice when it erupts again.

    • A hot spot seems a near certainty. Consider: if the second of the three fields you mention extends across the full widths of both California and Nevada to reach into Arizona, that’s either ridiculously huge or it’s a long narrow track at that scale. The latter all but screams “hot spot track!”. The Arizona end is the active end, I presume?

      The other option would be that the North American plate ate something that disagreed with it. Some slab that just won’t sink, and is bumping along underneath the plate banging into its basement and generating subduction-style melt zones all over the place. That could leave one, or many, tracks from the west coast into Arizona, Mexico, etc. and could explain the large region of uplift: if the North American Plate is like a rug, this object is like a stray Lego piece beneath it holding a section of it up. Try not to step there while barefoot …

      • Exactly. An old subducted slab under south western USA would IMHO explain the high elevation of the whole area. Denver is insanely high really.

    • Thank you, Bill! It’s great to hear the various information and ideas in these comments! (And thanks for the clarification about the Pinacate field – I was puzzled for a while.)

  13. Hunga Tonga… looks like we have major stratospheric cooling in the Southern Hemisphere due to the immense amounts of water vapour thrown into the upper stratosphere and mesosphere. How much it will effect the NH this winter is uncertain, though it will be a “lab-test”.

    If it does lead to a wolf winter in the Northern Hemisphere and the hypotheses and speculations in the articles below are accurate… things could get emotional.

    https://www.severe-weather.eu/global-weather/cold-anomaly-stratosphere-polar-vortex-volcanic-cooling-winter-influence-fa/

    Second link removed for plagiarised content – admin

    • It’s interesting they’re finding a correlation with southern hemisphere stratsopheric cooling and northern hemisphere stratospheric warming. I live in the northeast of the US and when we have SSW events (sudden stratospheric warming) we normally have cold, brutal winters with tons of snow. They’re normally below normal temperature wise and above normal in terms of snowfall.

      This article suggests it may produce a negative NAO (North American Oscillation) which frequently correlates to big snowstorm tracks right over the Northeast.

      Wonder if this will materialize, and how you folks in Europe will fare.

      • I wasn’t sure about that conclusion since the cause of the current weather is very different from the past. I expect that our climate models don’t cover the excess stratospheric water well – we never had that situation before (perhaps after Krakatoa but that one produced far more dust). The models will be improved based on what happens next. I think there is a good chance that the extraordinary hurricane season is related to Hunga Tonga but that also will have wait for the models. Every time something new happens, we learn

        • Absolutely!

          This was such an odd event and a first in modern history (huge injection of water vapor). As many scientists have now mentioned, there would be an expected degree of surface warming from the excess water vapor (greenhouse gas), yet overall this is probably rather hard to predict and model as you mention.

          I don’t know what will ultimately materialize this northern hemispheric winter, but I definitely was wondering how the various oscillations (EPO, PNA, NAO, AO, etc) might be impacted or otherwise influenced by the water vapor injection. Even if there is some small degree of surface warming, having the NAO and probably AO pegged to their negative states could produce below normal temperatures locally in my area along with increased chances for big storms.

          Pinatubo was a more traditional large eruption climate impact with sulfur based cooling and about 1/4th the water vapor injection (IIRC), but it absolutely impacted the jet streams over North America and is believed to have had a hand in the March 1993 Superstorm (where the jets merged with incredible energy and amplified a powerful nor’easter).

          I can’t wait to see what happens one way or another!

      • NAO is ‘North Atlantic Oscillation’ not North American.

        I know that yet I almost always type it as North American lol.

  14. What a fascinating article!

    I genuinely did not know volcanism was intertwined into the Grand Canyon in such a way, and I certainly had no idea that eruptive processes were still possible in and around the area!

    Really enjoyed this one, and as someone else mentioned, it really made me want to go and explore the Grand Canyon in person.

    Thank you!

      • Roseanne, I live near the canyon just out of Williams Arizona, that being sain I find something amazing and educational every time I step off my porch . My neighbor was a guide in the canyon for like 20 years. Some of his stories of hiking that national park, I get a giggle and then all my attention is asking about things you just can’t find in books. There’s more to the stories and some blown out there, but always an educational experience when reading or walking on my property and mostly all I can think dang I wish water table was a mile deep like the canyon. It’s beautiful no matter what way you see the canyon rail car, vehicle, a raft or a donkey, or even on foot. It’s all spectacular no matter what.

        • Thanks, Travis! It is definitely a beautiful and dramatic landscape. I hope to spend more time exploring there.

    • If you’r’ familiar with Craters of the Moon, have a Google on that!

      • You might want to check out the extensive discussion under one of Chad’s comments.

        • Went through that the first time around. Thought the visuals on line lent something to the narrative. Gives the old Crater Rim drive from Halemau’mau’ to the sea a run for the money.

  15. I decided to improve upon the map of lava alkalinity that I showed in the Colli Albani article and made a better map that distinguishes as many as fourteen different series of magma depending upon potassium content, each shown in a different colour. Red is lowest potassium, then goes through yellow, green, blue, and purple as potassium increases. Here is the US in potassium content of volcanoes:

    Each circle is a sample, and has 2 % opacity. So the circles in the map actually show the average colour of many overlapping samples. Uinkaret is a dark blue – purple, while Craters of the Moon is dark blue, and San Francisco volcanic field is a greenish bright blue. Cascades are green, locally with a hint of yellow or blue. The Gorda and Juan de Fuca ridges are red like almost every other mid-ocean ridge in this map.

    • The most potassic volcano shown in the map is Dotsero which is the brighter purple dot in north-western Colorado. In reality there a few more potassic volcanoes in the US, like probably Hopi Buttes or Navajo. However I filtered out highly olivine-phyric magmas from the map because they were difficult to classify together with the rest, so magmas like kimberlites, lamproites, melilitites, some basanites are not on the map, including those of Hopi Buttes or Navajo. But their crystal free or evolved equivalents are.

    • Shows how non alkaline the ridges are with their larger more shallow melt rates and depths

    • Héctor, what a unique map and what a lot of effort it must have taken to asseble it. As a layman, I’m trying to understand what these variations in lava alkalinity mean. So, spreading ocean ridges are low in potassium. The resulting Cascade volcanos are somewhat higher. Continental interior volcanism is generally higher still. It seems that that different geological processes result in different magma compositions, but, what does it mean beyond that? Why the focus on potassium? I’m missing the big picture.

      Thank you.

      • Thanks Jimp.

        I’m also trying to understand the significance of differences in alkalinity. There are some ideas I’ve been working on, but they are not ready yet. Generally mid-ocean ridges have lowest alkalinity, volcanic arcs take intermediate values, and intra-plate volcanoes have the highest alkalinity. But then there are many variations in between volcanoes of the same setting. You can have “orange” volcanoes in a volcanic arc, as you can have them “purple”.

        Alkalinity is the most important variable of geochemical composition in between volcanoes. Usually one volcano has a characteristic alkalinity, and this difference shows in the concentration of almost every element, trace element, rare earth, and even volatile element that magmas have. Potassium is a good indicator of alkalinity, the more alkaline the more potassium it has. So I made the map from a plot of K2O against SiO2. I could have used phosphorus and aluminium all the same, or some other combination, but I’m more used to handling potassium and silica, so it was more convenient.

  16. OK, that’s enough boredom for one week. Could someone in Reykjavik please send out a janitor with a plunger and a can of Drano to go and unclog the volcano?

    • Seriously?!?!? You think this is Twitter or YouTube Comments?

      • Relax! The discussion climate here is usually quite open and a quick joke like this is nothing to get upset about. The eruption was happening in the best possible place and was causing no harm. I think a lot of people wish it would continue for a while longer and I reckon a lot of those people are from Iceland.

        Remember that the most important rule of this blog is “be nice”. Other than that almost anything goes. Oh, there’s also a rule to leave moderation for the moderators and since I’m not one I’ll just leave it at that.

          • Agreed with apologies. The sophistication of this august body raises the expectations of a well constructed comment absent any editorializing. Such is the nature of social media that one never knows when some oddball has made it through.

          • Volcanoes reward good behaviour. Apparently. The admins rarely have to interfere and eruptions from admins are really rare. Almost all people mean well, and if an occasional comment goes a bit off the rails, others tend to give helpful feedback. I like this place.

          • RE:”I like this place.”
            I also and speak very highly to others of the level of expertise amongst the contributors to the many matters under discussion.

  17. Although nothing major, I noticed that Ischia in Italy had about 4 really shallow earthquakes on the north western side of the island today. I think this is the first I’ve seen anything in that area.

  18. Taal’s active SO2 degassing has dropped into the double digits, despite sustaining 2km+ steam plumes and increasing inflation.Something doesn’t seem quite right with that

    • Why the extreme volatility in Taal’s degassing? It’s interesting to me how it swings between extremes. Is this considered normal behavior for it (somewhat assuming so)?

      Do we think the decrease are from newer magma adequately degassing and then naturally subsiding its gas output, or does Taal waver somehow between blockages in its conduit system and bypassing of those blockages?

      Taal is uniquely interesting to me as a volcanic system.

    • Also, what’s Cerro Negro up to? Outside of the eruption drills taking place at the back half of August by the surrounding population centers, I haven’t heard much lately.

      Status quo?

      • I am thinking that whenever magma gets too shallow at Taal, it degases and cools, and temporarily plugs the system. Something is definitely wrong at the IGEPN, none of the maps for volcanoes are working for reasons I am not aware of. They’re not sharing any data and it’s been months since we’ve had a comprehensive report. My best guess is that the magma at Cerro negro has reached a major plug and is building pressure . Whether it would actually break the plug is a different story.

        • Thanks Tallis!

          And I suppose to a certain extent the inertia of millennia long dormancy would have to apply, meaning it’s more likely the system continues to contain the building pressure.

          Though, eventually that pressure has to reach that critical point unless it were dead, and it’s not.

          Regardless, still feel Chiles Cerro Negro is the one to watch if you like large scale volcanism, data collection issues aside. I eagerly await any updates if you’re able to happen across better information sooner or later.

  19. At the bottom of another chasm lies the highly agitated Zambesi river. Despite my uncertain fate I did have time to observe the perpendicular basalt walls up to the high water mark, whilst the maelstrom raged about. Black and unyielding resistance, but smoothed with such fine workmanship as to reinforce admiration for the persistence of running water. The more chaotic erosion of the volcanics lay above the high water mark, and it was from here, I suspect, that the many great chunks tumbled down to enrage the hydraulic forces even further.

  20. 2022-09-01 05:02:39
    Earthquake
    Magnitude:3.7M
    Depth:-2.1mi

    Was reviewed, NW of Mauna Loa.

    • What does pre-eruptive activity normally look like at Mauna Loa?

      Would think a new eruptive period will be starting in the near future eventually, and it’ll be interesting to see if it truly does downtick the productivity of Kilauea.

      • Before the 1975 eruption, there was snowmelt in Mokuaweoweo, but since that was 4+ months before the eruption, there’s a correlation/causation problem. There were swarms periodically, but there was no red flag indicating ‘*this* is the one”. Both 1975 and 1984 exhibited 1/2 to 1 hour of harmonic tremor before the eruption.

      • I think that Mauna Loa and Kilauea do interact but it is not so extreme as it can sometimes appear. Kilauea is nearly always extremely active. Mauna Loa is more periodic, during which time it can be as active as Kilauea or possibly even more so, but also long periods of inactivity, like now.

        Mauna Loa was in an active stage up to 1950, erupting every few years. But its most productive time historically was from 1855 to 1881, a time when Kilauea was also generally very active just not outside its caldera. Kilauea was not very active from 1924 to 1950 but Mauna Loa was also not extremely active either, it did large fissure eruptions but had no open lava lake existed there like sometimes in the 19th century particularly between 1868 and 1877. That open lake is indicative of a high supply, so actually the fact Kilauea did have one throughout the time Mauna Loa was supposedly dominant might mean it was getting much more than we thought and that it was not reaching the surface (going to ERZ storage presumably).
        It takes a colossal heat flux to maintain a lake like that, Kilauea in the Pu’u O’o era consistently had a heat output of between 300 MW and 1 GW, almost 3x that of any other volcano. It is probably somewhere comparable today.

        I expect a future eruption in the next few years, but it will be like 1975 and be a summit eruption. Then some time in the decade following a larger flank eruption, but not affecting Kilauea. I think we will see some more huge eruptions from Kilauea though, 2018 was evidently just a slight setback despite the magnitude of the event.

      • I think that in terms of actual immediate precursors though, it will be similar to recent eruptions from Kilauea. That is to say a summit eruption will happen after an hour of strong seismic activity around the active magma system which, unlike Kilauea, is largely restricted to its caldera and the chain of pit craters to the southwest. If it does a flank eruption then the best way to say it is that there will be absolutely no doubt what is going on. The entire island will light up on the quake map, and people will feel them. When it breaks out, it will glow like the entire island has been set on fire. Mauna Loa is not a volcano that leaves you asking questions if it is erupting or not… 🙂

        • Yep, Madame Pele seems to favor the SW corner of Mokuaweoweo–1914, 1933, 1940, 1949 all focused there and 1975 and 1984 passed through the same area initially. Only outlier is 1942, and why was that? Hmmm…

          • Yes, same fissure almost exactly. 1942 maybe followed a ring fault, there have been other eruptions in that part although not leaving surface exposure today. You can see the collapse structures, which could be from 1868 when the caldera collapsed. Incredible how both Kilauea and Mauna Loa had collapses that year, and high fountains at the summit during the quake. And then the massive lava flood down in Kahuku. That might have been the last event of comparable magnitude to 2018.

  21. Just took a peak of the area on Google earth, only shows around 7000 feet of elevation?

    Mac

  22. The Iceland Meteorological Office seems to have changed or removed some webpages, providing drumplots and tremor data (my old bookmarks failed this late afternoon) Here’s the current “data well” as they call it https://hraun.vedur.is/ but can someone who knows Icelandic language poke around and find the drumplots index page and the tremor pages?

    This effort is appreciated.

    • They handle https in an incorrect way. Remove the s so it reads http://

      • You are correct, my Mozilla browser is forcing an https:// connect not a regular http:// connect. I have to change a setting under the privacy and security tab

    • It was NOT the IMO who changed anything, it was Mozilla Firefox which I recently rebuilt which forced the http connections over to https, but the odd response of the IMO website after the browser was forcing this change, the website simply said cannot find the folders/location (which is true, because the https code is not there)

      I spoke up presumptiously in my post, careful investigation shows the true cause.

      Yesterday I was struggling with fixing many browser issues as the security certificates were also affected.

      • I had the same problem with Chrome last year; so, Firefox is not the only browser that does this.

  23. A recent Looking pyroclastic cone on the Moon. Probaly is 1 billion years old
    So moons last very gasps souch cones are tought to erupted water vapour rich lava that cooled into glass beads. I guess now 1 billion years later that the moons mantle really have shut down .. only heat left is around the core

  24. Is there any recent news on Fagradalsfjall? IMO geologist opinions, INSAR maps, GPS, tremor, etc.?

    • Nothing worth mentioning. There was a minor swarm this morning at the location of the eruption.

    • Ah, so the greats are slowly going….

      First feynman then many others,

      • There will be new greats. It just takes time for them to be recognized

  26. This was a good read regarding Grand Canyon tectonics:
    https://watershed.ucdavis.edu/education/classes/files/content/page/Ch3_GrandCanyonTectonics.pdf

    Has been a great deal of uplift underneath the Colorado block (and magmatic escape largely around its edges) but the block itself seems to be mostly intact and impervious to damage, though it has warped the surrounding plate/microplate/blocks in most directions. The Rio Grande Rift is a consequence of this.

  27. There has been lots of talk about types of lava recently here.
    It is very interesting! Much to learn!

    I am very intested to go to the upper right cornerarea of the TAS diagram though… 😊

    How large/far can a Rhyolite flow grow/flow? As far as I know these are mainly small, local.
    Can a rhyolitic flow be 20 km long?

    • Not sure if there is any real limit, they flow a lot slower than a basalt flow but also cool a lot slower too, because the flows are usually so thick. I know the lava flow from Puyehue-Cordon Caulle 10 years ago was supposed to still be moving over a year after the eruption stopped.

      There are some really huge rhyolite flows from Yellowstone, from about 75,000 years ago. These are the biggest lava flows erupted from any volcano in the past at least few million years, being of a volume that is bigger than Tambora if explosive. Those flows erupted from fissures so hard to tell how far they could have gone in theory, but the longest flow in reality went about 18 km from the likely location of the vents.

      I dont really know if you can get flows bigger than that though, 80-100 km3 is enormous, and especially considering these were not associated with caldera collapse. Probably most rhyolite eruptions that are of thos scale or larger would be explosive.

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