Activity update around the world

Etna has had its ‘paroxysm’ #many. Every eruption is spectacular, but when they are so frequent it gets easier to focus on what is different with every eruption. Bruce Stout and Newby noted that the activity lasted much longer than previously in this series of paroxysms. Why this is, is off course a mystery, but maybe as time progresses we will find out if this is again some kind of new behaviour for Etna. For now, I don’t think many people mind that Etna keeps doing these things, since the eruptions are not much of a nuisance to the people living around it (at least, not more than usual with Etna’s eruptions), but are nice to watch for everyone.

Mr. Behncke of the INGV in Catania has written a nice summary / eyewitness report of the activity, which can be read on his Flickr-photostream. The question is indeed if this longer-lived activity can still be called a paroxysm.

Webcam image of today’s paroxysm. Image by INGV

Inge B. pointed to some images released by the INGV showing the Italian island of Vulcano, which seems to show a bit of unusually strong fumarolic activity.

Eolian island of Vulcano. Image by INGV.

The island is known to be volcanically active in recent history. The last eruption has been recorded in 1888 at the Fossa cone. The cone can be seen in the webcam image above. The Fossa cone has been the main center of activity in the last centuries, and fumarolic activity and gas emissions are ever-present to some degree at the Fossa cone. Sometimes, the activity peaks, like for example in 1985 and 1990, which shows that the town at the bottom of the Fossa cone is still under constant threat.

The Vulcanian town of Volcano Porto at the base of the Fossa cone. Image by INGV.

The island of Vulcano is off course most famous for being the place that gave volcanoes their name. In Greek and Roman mythology, the god Hephaestus, or Vulcan, was the god of fire and was thought to have its workshop below the Eolian island, leading to the frequent release of fire from the mountains on it. It is also the type locality for one of the 5 main types of magmatic eruptions; Vulcanian activity. This type of activity is characterized by viscous magma, andesitic to dacitic, that frequently erupts explosively and generates volcanic blocks and bombs that rain down on the surroundings. For comparison, Sakurajima is the best example of Vulcanian activity in recent years. The area where the volcanic blocks and bombs rained down during the 1888 eruption on Vulcano is where the town of Volcano Porto is now built, leading to the constant threat mentioned before if Vulcano decides to really wake up and go back to the behaviour the ancient Romans knew it for.

Meanwhile, Tolbachik seems to be re-thinking it’s decision that the eruption has now lasted long enough. Strong seismic activity has been recorded, together with strong gas-steam activity and a big thermal anomaly was seen on satellite images. Estimates of the erupted volume are well above 1 km3, so this number continues to rise for now.

Also, Granyia noted that the Chilean volcano Lascar had seen its alert level raised to Yellow, after reports of small explosions and some ash in steamclouds. Looking at the webcam, it looks like some glowing can be seen. Sernageomin reports (.pdf, in Spanish) that during a helicopter flyover, temperatures above 600 degrees celcius were measured in the crater using a thermal camera, which confirms the reports of glowing at night.

Lascar webcam image. Image by sernageomin.cl

El Nathan

———————————————————

Post update by Spica:

The Sheepy Dalek bar is open and Alan sent in another Evil Riddle:

I shan’t beat about the bush – a real spiny subject this, but at least you wouldn’t need a tv aerial!

What am I?
What are my special properties?

Good luck and have fun!

Alan C.

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356 thoughts on “Activity update around the world

  1. OT, but geological.

    The island of Crete was lifted about nine meters in 365 AD. This was the result of what is beleived to be a Mag 8.5 (or so) earthquake.

    http://en.wikipedia.org/wiki/365_Crete_earthquake

    Nature has an article resulting from analysis of the megaturbidite deposits (disturbed sediments)

    http://www.nature.com/srep/2013/130215/srep01285/full/srep01285.html

    Of note is that the Roman Empire fizzeled out in this era. Wiki has the date as 476 AD. This is a bit of an inaccurate view of history. Rome didn’t arbitrarily “fail” on a given date or year. It suffered a slow decline and then ceased to exist. The citizenry living in the period did not think of themselves as “I used to be a citizen of Rome,” in their view, they still were Roman. It’s just that stuff didn’t work quite as well as it did the previous year. Food became short, the defensive systems were not as workable, and invaders kept pouring through ransacking stuff. This quake and the devastation that it caused throughout the basin contributed to that decline and eventual fall.

    Technically, Rome really didn’t fall. The seat of power moved to Byzantine around 330 AD and continued on until the Ottoman Turks finished them off in 1453. (helped, in part, by crusaders from the remnants of the Western Roman Empire who had weakened them).

    The object lesson?

    NOTHING is “Too big to fail.” That is unmitigated horse-shit.

    Eventually, even the Sun will fail. (hello red giant phase)

  2. OT: Amusement.

    In the Movie 2012, a video segment that was put to Yackety Sax and that I linked to a couple of day ago, you can see some really awesome theatrical effects and some pretty shoddy geology. I found another clip from it, and in it, the magnitude of the earthquake that is at the start of the “all hell breaking loose” segment is stated as Magnitude 10.9.

    For shits and grins, I ran that through the Wells-Coppersmith equations to see what the math states that it would be like. Per the movie, where it got nasty was when “the sister faults” became active. Not a bad call, something that large would have an effect on neighboring systems. So… San Andreas – Strike Slip. Mag 10.9. (larger than anything ever recorded)

    Max displacement – 15.9 km. MMI-X out to about 240 km. Peak acceleration 193.1% g. It would literally be a mess, though probably nothing like what the movie depicts.

    Here is a subtitled version if anyone wants to see this geological stinker… but the effects are thrilling.

    • Still nice to see though, although the story, the science and the acting are all horrible.

      At this moment, about 25% of all energy released by earthquakes since begin 1900 has been released by the 1960 Valdivia earthquake in Chile at M9.5. I guess a 10.9 would immediately decimate all other quakes measured and would consume +/- 119/120th (99.2%) of the pie chart 😀

      Coincidentally, Cordon-Caule erupted 36 hours after this, which is some 60 km away from Valdivia. For as far as I know, this is one of the best examples of a volcano being triggered by an earthquake. One can only speculate what a 10.9 would do, but I guess it would be almost cartoon-like with mountains falling of their base, huge landslides all over the mountains/hillside, tsunamis reaching all the way to Australian mount Uluru and crossing the Andes etc.

      • http://quakesim.org/tools/moment-magnitude-calculator
        A very large earthquake rupturing a fault 500km long and having a slip of 80m would be magnitude 9.4.

        Let´s go to the limits of possibility: an earthquake rupturing the largest extend of a fault in the world, would not be more than 1000km. Let´s say a slip of 200m, which is rather unthinkable. Magnitude is 9.9. Even if such a large fault 1000km ruptures entirely and slips an astonishing 1.5km, then this still gives a magnitude 10 earthquake. I am not sure if such large slips can occur. Apparently not by geological records. Such a earthquake would cause probably enormous shockwaves and tsunamis.

        If the fault slips 100m (much more likely), then this gives the most likely max magnitude of 9.7. I think this would be the average maximum magnitude possible. Still very catastrophic.

        Magnitude 11 is impossible, unless there is a large asteroid or comet impact. Its a slip of several kms over a region 1000km wide.

        • If the “2012” earthquake of M10.9 and a slip 15.9km would occur, it would cause horrendous tall tsunamis if nearby the ocean. Similar to a large asteroid impact. I am not sure on the physics about how tall such a wave would be and how far inland it would go, around the world. Still unlikely to happen, because a fault tends to break when it reaches an average slip potencial of around 50 to 100 meters. Such a 15km slip is almost impossible to occur.

      • there is a record of a more then 200m tsunami on the South-east coast of Australia, most likely from an EQ in South America ?
        once you are over the great divide a lot of land is as flat as a pancake, so it could travel all over the place if it finds a gap of sorts

    • Hekla strain has been going down for 36 hours now. I often wonder why that borehole doesn’t show the fluctuations the others do. Burfell for instance always looks like a switchback ride, Hekla just one long climb up then one long slide down.

      • The paper is about preliminary observations from “ant-cams” close to the Laacher See in the Eifel volcanic field. Manual analysis is compared with automated image evaluation. The result is pretty much anecdotal so far: “According to our first analyses, clearly anomalous ant behavior occurs for the local earthquake on September 10, 2009, with a magnitude of 3.2. At lower magnitudes, an anomalous behavior may possibly be present as well”
        I guess further analysis will be statistics hell…

    • I have seen what I thought might have been one yesterday… but it is too far away to say for certain. There is a light coloured “Rutschbahn” (slide, chute) on the slope and on that steam or dust was visible. Could be a fissure where steam was rising from, a lower vent, or a flow, pyro or lava

  3. Afternoon all (UK time). Just doing a pre-dinner rummage when I notice tremor at Grimsfjall is doing interesting things. All rising quite rapidly. Also, some rather fidgety harmonic looking stuff off the north of the ice cap at the Dyngjuhals station. I know they’re due a gale, but that to me looks like Grimsfjall is working up to its own paroxysm?

  4. Tremor plot MJO at Hekla showing the storm now also. http://hraun.vedur.is/ja/hekla/ Also to be seen at the GFZ webcam, and the dark clouds are from ash, not from Hekla, but reactivated ash from Eyja/Grímsvötn eruptions (corr. also to IMO forecast “öskufok”).

    • I saw that video and read about it a couple of months ago now, so wonderful that someone was able to help a dolphin for once as they are quite renowned for helping humans who get into difficulty in the water, usually by assisting them to the surface. Something they would do for a sick dolphin but how do they know a human is in distress? Do we give off similar signals I wonder? Probably as we are both alike in having that same need for air.

  5. Had another look at Grimsfjall and it is way more than the storm showing up elsewhere. To my mind (whatever’s left of it) that looks like something is going on. There’s a steep rise and a hint of harmonics now (possibly – my eyes are a tad iffy). If you take a look at other stations around the south activity from the storm is visible but not quite the same. I’m going to keep an eye on this! (48 hours later….fast asleep 🙂 )

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