Sakura-jima – What type of lavas does she produce?

A quick re-cap: Sakura-jima is a post-caldera cone of the Aira caldera. She emerged roughly 13,000 years ago on the southern rim of the caldera, building an island which was eventually connected to the Osumi Peninsula during the eruption of 1914. She is located near the junction of several tectonic plates, whose movement drives eruptive activity.
Sakurajima’s lavas have tended to be andesite – dacite. But she has produced effusive lava flows.

Lava rocks along Nagisa Lava Trail on Sakurajima, Jakub Hałun, 2012, Wiki Commons.

In 1914, lava’s filled the strait between the island and the mainland. The 1914 eruption started as explosive with an eruption column and pyroclastic flow. Effusive lavas were produced later after a large earthquake. During the later stages of the eruption the centre of the Aira Caldera sank which seems to indicate that lava is sourced from a common reservoir. Other effusive eruptions occurred in 1471 (believed to be her largest recent eruption), 1779 and 1946.

Kagoshima covered in ash. NYPL Picture Collection — Illustrated London News, 1914, Wiki Commons

A study by Goto, H Ishibashi, T Yanagi looked at the temperatures of her dacite lavas. The temperatures appear to be a consistent (850°C) with few magmatic inclusions in the lavas. The lavas contain phenocrysts of plagioclase, clinopyroxene, orthopyroxene and magnetite. These show a bimodal distribution of plagioclase phenocryst compositions. This implies a) injection of basalt magma into the resident magma chamber; and, b) the magmas are well mixed before eruption.

Yanagi et al (1991) had found that the lava flows became more mafic with time from an initial dacite composition. They proposed a two chamber system with a plagioclase pyroxene plug separating an upper dacite chamber from a lower basalt chamber.

Nagel et al researched this further looking at 12,000 years of eruptive history. They discovered that there was a cycle of mafic and more felsic lavas prior to the 1471 eruption. After the 1471 eruption the mafic content of lava has increased to 55% of the dacite lava showing magma mixing. They propose a shallow dacite magma chamber which is repeatedly flushed with mafic magma from a deeper chamber.

Since 1914 Sakura-jima has been relatively quiet; eruptive activity has been mainly ash, lava bombs and gasses, which may or may not be accompanied by earthquake activity.


“Petrochemical evidence for coupled magma chambers beneath the Sakurajima volcano, Kyushu, Japan” T Yanagi, Y Ichimaru, S Hirahara – Geochemical Journal, 1991 –
“Apparent temperatures estimated from pyroxene phenocrysts in dacites from Unzen, Kuju and Sakurajima”, S Goto, H Ishibashi, T Yanagi –
“Temporal Geochemical Variations in Lavas From Sakurajima Volcano, Japan”, Nagle, A. N.; Harpp, K. S.; Geist, D. J.

92 thoughts on “Sakura-jima – What type of lavas does she produce?

    • 😳 missed that one.

      Also forgot to mention that the post 1946 lavas are andesitic (pyroxene, labradorite, hypersthene, augite, magnetite, pyrite and very rarely anorthite).

      Hypersthene, Augite, Anorthite

      Comes of cutting back on the caffeine intake again.

      GL Edit: Inline added, links shortened. Left them as links to avoid slowing the page load.

    • Hi Lucas, I think a review is a great idea, thanks for putting in the time 🙂
      P>S> look out for an email from lizzie… she wants to ask you something… I’m not allowed to know apparently, something christmassy I guess 🙂
      P.P.S Geolurking; thanks for the beery ruminations on EL Hierro (few pages ago) just what I was asking about…

  1. Good to see her cough occasionally (screenshot from the 373news webcam 3 days ago).

    And while the Tjörnes fracture zone has taken a break during the last hours I made a new 3D plot for the last 28 days (time colorcoded), plus activity from 2011 (green) plus events (>1.4) from 1995.
    This is a close-up view of the corner Kolbeinsey ridge – TFZ. The most recent earthquakes are now deeper on average. Additional to the few small earthquake stretching south, that we speculated about being the harbingers of rifting nightmare a few pages ago, there are now also some heading north west.

    Today I found out that when you upload with a relatively low quality (small size, 640 x 480 “recommended” for Youtube by Microsoft Movie Maker) Youtube processes it to become much much worse. I now chose high definition (1440 x 1080) which gives a quite pleasing result instead.

    Any news from Carl? He won´t miss the party on Thursday, will he?

    • You guys are making me jealous. Each plotter has their strengths and and each presents the data in a really clear and easy to visualize manner.

      I am quite impressed! Each program seems to have their strong points and they are beginning to be put into use with each incarnation.

      Why the jealousy? I can’t “wall” an overlay map, and in order to do transparency I have to manually tweak the data set. On the fly updates to the plot are difficult to do.. unless I wish to learn a new language.

      You guys are getting quite good at this!

      • Thank you very much!
        It is such a joy to have such friendly team mates who help to bring out the best of each others plots. Seeing what is possible in other programs seems to triggers ambitions in each of us to copy the effect. For example, I have not figured out how to dynamically control viewer perspective like you guys do. The rocking chair is great!
        And Geolurking you can be proud of your analytic capabilities, to ascend to your level we others have to go a looong way…my Kudos to you 🙂

    • Well.. how about that. I’m in the ballpark!

      This is from an attempted implementation of Atkinson-Wald’s ““Did You Feel It?” Intensity Data: A Surprisingly Good Measure of Earthquake Ground Motion”

      Click to access AtkinsonWaldDYFI.pdf

      I’ve been fighting this one for a couple of weeks.

      It’s used to determine the effects that buildings and people feel at a specific range. There is a related document that takes population exposure and local conditions into what the projected casualty rates are… you usually see the results of that in the PAGER reports for the quake.

  2. Fantastic post (now that I have actually had time to read it :D)

    First, I was un-aware that the spit of land that connects it used to not be there. (historically speaking)

    One question that I have about Sakura-jima is the lay of Kagoshima Bay. That’s a pretty significant cut into the island. Sure, Sakura-jima is essentially a nascent Somma Volcano, rising from the Aira caldera, but what of activity prior to Aira? (22,000 ka VEI-7 ≈400km²)

    Was that bay cut by predecessors to Aira? With the subducting Philippine Sea Plate moving NW at about 48 to 71 mm/yr, and the eastern side of the back-arc basin moving SE at about 54 mm/yr (Okinawa_Plate), I imagine that the magma production for that line south of Sakura-jima is or has been pretty significant.

    • Lurk, have a look at the photovolcanic link I added below. There is a discussion of this towards the end of the article. They also question whether Sakurajima is actually a somma volcano:

      “Interestingly, even older eruptates and material erupted at Sakurajima volcano are all andesitic / andesitic-basaltic, suggesting that the caldera-forming eruption involved a distinct magma body. Models for the magma bodies for present-day Sakurajima and that associated with the Aira Caldera eruption have been compared, with mixing of dacitic and basaltic magmas implicated in current activity, in contrast to a large rhyolitic body primed by basaltic magma from beneath implicated in the latter (Arakawa et al. 1998. J. Volc. Geotherm Res. 80, p.179-194). Given the different source magmas and presumably magma chambers, it is possibly questionable whether Sakurajima can rightfully be regarded as a continuation of activity at the Aira volcano, rather than a distinct volcano in the same geological complex.”

      • Probably am wrong as I have just re-read my own posts!

        I was interested in the divergent plate boundary near Sakurajima which, combined with the subduction of the Philippines Sea Plate, could cause different magma types. The former more basaltic and the latter more silicic.


  3. Indeed, fantastic post Karen. Love the way you can bandy about the names of the minerals because you are totally at home with them… something I really appreciate as my eyes still glaze over words with more than 3 syllables but I am working on it.

    I can’t remember if you provided this link with the first post on Sakurajima but photovolcanica have got a great site on Sakurajima too. It might be quite good to add it to the references:

    I have a feeling that the combination of deep mafic and shallow dacite chambers could be quite a common pattern among calderas, even when there is no mafic signature in the erupted products. The heat from the deeper chamber alone might play a role (though how the heat would then be actually transferred without melting the country rock between the two chambers is a mystery.. maybe volatiles in fluid form or something?)

    • …err, reading that again, I got the emphasis a bit wrong. I actually think mafic intrusions into shallow felsic bodies is the standard mechanism for caldera forming eruptions. I was not trying to suggest otherwise, just pondering whether it could work without a mafic intrusion to trigger the eruption.

      • I read somewhere a while back that it was suspected that Sakura-Jima was actually fed from multiple sources, including intrusions from the Aira Caldera chamber, as well as another magma source that is fed from the south of Sakura-Jima. Considering that almost the entirety of Kagoshima Bay is volcanically active (including the Ata Caldera just to the south of Aira), this doesn’t seem all that unlikely, and could help explain how there are multiple magmas coming up in the area from multiple locations.

        With that said, I’m about 98% positive that sakura-Jima is in face connected to the Aira Caldera. I believe quake maps have shown intrusions coming from the Aira caldera source chamber, but once again, this is just going off my memory from some reading I did a while back.

    • Thank you. I wouldn’t say totally at home with the mineral names but have learned a lot through the riddles here and research. I couldn’t have done that a year ago quite so comfortably 😀

    • Didn’t use the photovolcanica site for this post; I found the papers via Google Scholar. However, I did use that site for the first post on Sakurajima and it is included in the references there (just checked).

  4. Isn’t that the cafe’s birthday?
    Congratulations and many thanks to all that make it what it is. Great example for science being fun.
    Have a nice day.

  5. Heh.. I barfed a program.

    When the memory usage got to 1.52 GB I sort of realized that it wasn’t going to make it. It croaked. No big deal, I just had to take a different route to digest the data.

    I had run a simple Mag 5.6 though it and came up with what looked like a good formula.. then I realized that it ran into issues when the MMI got too large… according to it, you got negative gravity. (yeah, I know… but tell that to the program)

    Anyway… taking a different tack, I get this…

    Below MMI-5 -> 10^(-1.451+0.457*MMI)
    Above MMI-5 -> 10^(-1.061+0.3788*MMI) (general maximum percentage of gravity felt in region.. can vary by as much as 20% depending on terrain)
    Above MMI-5 -> 110^(-0.1844+0.2038*MMI) (general minimum percentage of gravity felt in region.. can vary by as much as 20% depending on terrain)

    Yeah… it’s math stuff. Mainly aimed at the plotters.

    But in a Magnitude 9.0 quake (very rare, but they do occur), you can get MMI XII quite easily at the epicenter. MMI XII (12) works out to somewhere between 182.5 %g to 3052.1 %g.

    BTW, one “g” is the amount of force that you feel as your weight. If you weight 150kg, at 200%g, your apparent weight would be 300kg. With upwards of 3000%g.. I imagine stuff was tossed pretty high into the air. The Love and Rayleigh waves would be the ones doing most of the tossing. (Keep in mind, this just an estimate… by an amateur)

    And if you read the description for XII… pretty much everything is being thrown up into the air. Wholesale destruction. “Catastrophic” is the phrase used in Wikipedia. That little exercise explains why Anchorage looked the way it did after the 1964 quake… a Mag 9.2(Mw). Chile topped that with a 9.5 in 1960.

    No.. no reason for doing it. Was just curious.

  6. A great Post Karen. Thank you. And also thanks to Cryphia for another lovely plot. Bruce I tend too to skim over long unfamiliar words… a very bad habit I know but I have done well to manage to read this post and comment.
    I am still in puppy- nursing mode so my ruminations are still sort of Puppy pooh aligned. Meg is NOT a very femmine K9. :). I will say little about our greatest concern except she now has a “pooh Place” So the somewhat volcanic style eruptions have been kept in one place and also I note this morning less Plinian thank goodness. We have been worried but it looks now like it’s a case of recovery from stress and underfeeding. She’s so much more settled and very happy. She’s very intelligent…….She found that with one foot on a box, carelessly left by the kitchen counter, and using the other extended paw she can slide plates and objects, that are left at the back of the work top “out of her reach” , to within munching distance. My main rumination today is…… Carraway seeds expelleth the wind ( According to old herabalists and my Grandmother)…. What effect will I experience today since Meg managed to wolf down the remaining half of a large, really good seed cake I had made!
    Either the incredibly horrible, smelly, degassing of the last three days will increase or be decreased.
    I wonder if I can buy a gas mask on eBay cheap?
    I hasten to explain, this is not one of those small, jolly, roly-poly, fun bundles of fur . She is more like a Wiley Coyote in development. Long greyhound like head, legs and body and already well past my knees in height and eyeball to eyeball when she puts her feet on my chest. Sight hound eyes that miss nothing, a crumb, a dead carrot that rolled under the kitchen units weeks ago that I missed, the squirrel way up in the trees ! Combined with Either Collie or Alsatian intelligence. She’s certainly keeping us on our toes and seriously is a joy to train and play with. Already a great companion.

    • At least yours has a talent. This Pica-juaja’s only talents are chasing laser dots, flies, and having the ability to “hold his water.” I never knew a dog could hold that much fluid relative to his body-mass. I think he is part water balloon. At least he takes it outside.

      • My bitch makes me rethink all I thought to have understood about physics and chemistry. She shits more than she eats. So, after all, who finally knows, maybe the perpetuum mobile can be realised.

      • I have Springer Spaniel.His claim to fame is he remembers every place we stop for
        a draining and poop.If he is there and marks it once, he remembers. We often travel
        over the freeway pass between La Grande Or. and Pendleton. There is a rest area at
        “Deadman’s Pass” If you are within one mile he starts lowlevel whine.then the kai yai
        yipping as you get closer. then the scratching at the van door as you pull off the freeway.
        beenthinking of doing a you tube.It is quite a show….

    • Dogs and their excretions… I can make mine poo as much as I want, when I arrive at my parents place, where there are no more rules for kids and dogs (absolutely not corresponding to my memory of ~30 years ago…), she gets so excited that a cherry-tomato-sized piece of shit falls down her ass. Madness.
      Your Meg has most beautiful eyes. It really seems you found a fine companion.

    • Sounds fun ! We lost our dog last year but he was a real character. Had a thing about anything that flew – would chase and bark at birds as if they were a real threat to survival – even the tiniest was fair game. Letting him out in the evening would have him chasing bats in circles. We would often seem him scanning the trees for anything that moved when most other dogs had their nose to the ground. He was a weirdo – but we loved him.

  7. The area round Hekla has shown some signs of indigestion over the last couple of days. I wonder if the suggestion of major rifting activity up north and to some extent the south is having a knock -on effect all the way along the rift? It’s interesting to watch what will or will not happen. We are so lucky to be able to watch such incredibly well monitored activity. Iceland certainly is exceptional in providing this information as it happens. I am sure Japan also is way up there. Certainly their web cams are brilliant. Many thanks to all in Iceland IMO and all the Japanese people who help to allow the world to watch and become a little involved.

    • Thank you Diana!
      Reading your comments in the morning makes me feel like Pollyanna or Julie Andrews. I think I’ll just go to my class dancing and clapping hands!!!!
      Congrats for your new dog!

      • Awwwwwwww! I am glad I make someone happy 🙂 How is Brazil today? I was thinking of you as I am about to sell some old South American coins.I always remember being impressed with Rio. I had a National Geographic magazine, it must have been in the 1950’s and there was a picture of the promanade with tiles that made a wavey pattern. I thought it was so exotic and so far away. I wanted to go there, but never did!. maybe if I win millions I will go on a world tour by ship.

    • Yeah Diana, i think you are right about Japan, bad thing only is, i cant read Japanes, and i would not even dare having giggle translate run over it. I guess the results would be hilarious but not really informative.
      I Am glad about your dog, btw and enjoyed your descipitions lots.
      Ok it is not the weekend and those are a little off topic, but i enjoy the way they are written mad not too much is up volcano wise, so i hope you keep me informed about Meg. I also hope the others and Carl wont mind but i dont think so.

  8. Morning

    Happy anniversary to the blog !
    The Askja plot is still churning along, nearly finished the 2964 EQ plot and then just a little 360° rotation to do….please be patient !

  9. I have a… strange sense of humor. So to me, this is hilarious.

    The BBC is under assault for biased reporting. Not just the pedo stuff but the global warming slant. They claim that their view is due to “28 experts” in a past meeting. But they won’t reveal who. An FOI (or the UK equiv) was submitted, but denied by a judge.

    That list is now public. The legal wizards seem to have forgotten about Internet archive sites…

    • @GeoLurking: This hasn’t made the news this side of the pond. Do you have a link? The BBC are certainly having a lot of problems these days!

      • Yes Talla and just to remind people that everyone in the UK who owns a TV must pay a Tax on it , so really it belongs to the people. I am not happy about a certain pay-off for not doing his very well paid job recently. I only dream about having the amount he was paid!

        • Diana, have you ever considered what amounts of money have been spent on media gurus, media advisors, external bureaus, marketing know-alls, &c over the past few years? Than that salary for barely a month’s work as chief whip at the beeb… while I can’t listen to the BBC World Service on the AM anymore in the car! because they deemed keeping the Western EU broadcasting equipment up too expensive.
          Adam Curtis put up some red flags in his blog. I feel that’s the direction we have to look into for understanding some of what’s going on at the Good Ole’ Beeb.
          On a lighter note: what a lovely extension to the family is Meg! And: How is your husband’s arm?

    • Wonder why someone is attacking the BBC for biased reporting on global warming? New Scientist was attributing Sandy to global warming or climate change recently but they did end the article with the comment that we aren’t out of the last Ice Age yet 😀

    • The Secret 28 Who Made BBC ‘Green’ Will Not Be Named

      BREAKING: The ‘secret’ list of the BBC 28 is now public – let’s call it ‘TwentyEightGate’

      UPDATE3 – Barry Woods writes in an email to me:

      Don’t forget Mike Hulme Climategate email. why he funded CMEP, to keep sceptics OFF BBC airwaves… (below)

      Mike Hulme:

      “Did anyone hear Stott vs. Houghton on Today, radio 4
      this morning? Woeful stuff really.
      This is one reason why Tyndall is sponsoring the Cambridge
      Media/Environment Programme to starve this type of reporting
      at source.” (email 2496)

      let us also not forget, that Roger Harrabin BBC & CMEP – (and Greenpeace Bill Hare) were also on the Tyndall board from 2002 to at least Nov 2005.

      Bishop Hill coverage

      And the Omnologos site (he’s the one that found the list on the internet archive servers)

      Why the List of Participants to the BBC CMEP Jan 2006 Seminar is important

      A bit about Archive servers.

      Archive servers act as a way to find out what was on a website at sometime in the past. Many companies, vested interests, or whoever for whatever reason, edit their sites to either update them or to remove embarrassing information that they had previously posted. On some occasions, it is done to change the history of what was said. If you point to a reference, and it’s no longer there, then it’s your word against whoever you have the disagreement with.

      I’ve been around the net for a while, and from what I recall, Internet Archive servers have been around almost as far back as I can remember. (net wise)

      One of the more popular ones. The “Wayback” machine

      Browse through over 150 billion web pages archived from 1996 to a few months ago. To start surfing the Wayback, type in the web address of a site or page where you would like to start, and press enter. Then select from the archived dates available. The resulting pages point to other archived pages at as close a date as possible.

      Generally, the more popular sites are archived… and this can range from newspaper sites to major corporations.

      • Interesting list of attendees – not what you would expect for a meeting with scientists. From the way the list is set out it is not clear that many of them, if any, are experts on climate and weather – but that could be due to lack of detail on the list.

      • It turns out that pretty much none of them are scientists.

        Lance Wallace notes about the list:

        Lance Wallace says:
        November 12, 2012 at 5:26 pm

        I count three climate scientists with a technical education: May, Hulme, and Dahl-Jensen of the NIels Bohr Institute. Others with an academic affiliation (Bravo, Widdicombe, Smith) have liberal arts (history, geography, philosophy of science) backgrounds.

        Of the three “technicals”, two are activists. However, Dr. Dahl-Jensen seems to be an actual boots-on-the-ground scientist (latest grant is for drilling through the Greenland ice aiming at bedrock to investigate possible lakes at the bottom of the glaciers). I expect whoever was responsible for vetting her prior to the conference has since paid the price.

        Other attendees in this advisory group…

        * Eleanor Moran, Development Executive, Drama Commissioning
        * Jon Plowman, Head of Comedy

    • Watched this episode of “Yes Minister” (or was it “Yes Prime Minister”) yesterday:

      To paraphrase Jim Hacker one could question why the special Interests of the few, pedophiles, global warming, Barack Obama, should be subsidised as it’s nothing more than a left-wing intellectual rip-off. 😉

  10. Hi

    Here is (at last!) the video for Askja zone between October 2011 to Early November 2012.
    “Rocking chair effect” is included.
    The Moho is shown.
    Earthquake dot size is proportional to magnitude.
    Colorbar represents the terrain elevation

    It’s been a wee long, but there were 2964 events to plot….

  11. Better PGA and PGV estimates from MMI:

    PGV = 0.2915*1.867^MMI
    r² = 0.99588759
    Corr = 0.99794168
    Max Error = 4.7692056
    Mean Sq error = 1.6690877
    Mean Abs error = 0.90024009
    Sigma = 0.423878

    PGV -> Percent G


    PGA = 0.1886*2^MMI
    r² = 0.94656185
    Corr = 0.9729141
    Max Error = 6.302375
    Mean Sq error = 33.430585
    Mean Abs Error = 3.1871089
    Sigma  = 0.56737

    PGA -> cm/s

    This is just an estimate for about what can be expected. Though the correlation coefficients are pretty tight, the value can deviate from this quite a bit… “Black Swan” and all that ya know.

  12. Diane_ N_CA and Marktburns on Eruptions have noted yet more (small) earthquakes beneath Mammoth Mountain. This volcano is becoming particularly high on my ‘one to watch’ list.

  13. Sakurajima maybe where I first acquired an interest in volcanoes. We used to spent most of our summers with my Aunt Christine and Aunt Eleanor in Ipswich, Massachusetts. They had a large collection of National Geographic and one had an article on the 1914 eruption. Another had an article on Yellowstone. If I recall correctly, the color in it was done by watercoloring the black and white photos.

  14. Sorry for the OT… but I really think I need to plug this.

    At 01:00:00 Thursday November 15, 2012 UTC, the website Watts Up With That (WUWT) will begin web broadcasting “Counter programming to Al Gore’s ‘Dirty Weather Report’ will be on WUWT-TV Live starting Wednesday Nov. 14 at 8PM EST”

    Featured are a long list of actual experts with a pragmatic view of the actual science, ranging from Richard Lindzen (Alfred P. Sloan professor of Meteorology, MIT) and Burt Rutan, (Engineer and Aviation Pioneer) to Joe Bastardi (Lead forecaster, Weatherbell) and Christopher Monckton (SPPI).

    More info can be found here:


    Mag 5.6 2012 November 14 05:21:43 UTC Negros, Philippines.

    Not that there is anything significant with this event.. other than my MMI implementation of Atkinson-Wald (2007) matching the official plot from USGS. (“Woot!”)

    I haven’t determined whether I’ll make this spreadsheet available. It really depends on if someone want it.

  15. I just looked up Ruminations on wiki! 😯
    Depression? Distressed state of mind? What a load of Copralites!
    On the eve of Volcano Cafe’s 1st Birthday, I look back and see where my ruminations have led me.
    To Volcanoes and earthquakes of course. Biological peculiarities, Astronomy? Good grief !I have even learned about Volcanoes on Mars. Then of course there is nekkid volcanic dancing. The eating of hats. Vikings and the Aurora. Mathematics, physics and chemistry have come back into my life 50 years after leaving school. Volcanocafe has turned back my mental clock. Given me a new lease of life.

    I have never been happier than this last year. I have ruminated in the garden; In the shower;Whilst driving or cooking. I have even ruminated in public 😳
    Most importantly though it is the people here that have really cheered me; Inspired me; Encouraged me and made me giggle like a teenager .
    Thank you Carl and the Dragons, Lurking and all the VC Plotters, and everyone from all the corners of world who have created this unique place where serious science can share a bed with comedy and politics, philosophy and rock music, sheep and Daleks.
    Oh Horks! I feel a rumination coming on!…………..

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