Watching volcanoes from space: Part 1

Photographed by an astronaut aboard the International Space Station, Etna erupts on 22 July 2001. (NASA)

Photographed by an astronaut aboard the International Space Station, Etna erupts on 22 July 2001. (NASA)
(click on the images to see them at larger size)

On 1 April 1960 US Army Signal Corps pilot Captain William M. Templeton lifted off in a Sikorsky H-19 Chickasaw helicopter from Camp Evans, part of the Fort Monmouth complex in New Jersey, for the short journey to Monmouth County Airport. On board he was carrying precious cargo. At the airfield, Captains Lloyd J. Petty and Robert C. Jones were preparing their L-23 Seminole aircraft to speed the package on the next leg of its journey. After takeoff they headed south, towards Bolling air force base in the southern suburbs of Washington, DC. On arrival their cargo was put in a vehicle and whisked away to the headquarters of the National Aeronautics and Space Administration, and within hours was being presented to President Eisenhower himself.

What cargo could be so precious as to warrant such treatment?

Inside the package were the first images taken by NASA’s TIROS-1 (Television Infrared Observation Satellite), which had been placed in a low-earth orbit after launching from Cape Canaveral aboard a Thor Able rocket at 0640 EST that morning. TIROS-1 carried two TV cameras: one with a wide-angle lens and one with greater magnification. Within 20 minutes of launch the satellite was transmitting its first TV pictures to the ground tracking station at Camp Evans, where Signal Corps personnel developed the first prints. Although primitive by today’s standards, they clearly showed the planet Earth, with the swirls of clouds associated with weather systems.

The very first image of earth from space, recorded by the TIROS-1 satellite on 1 April 1960. (NASA)

The very first image of earth from an orbiting non-military spacecraft, recorded by the TIROS-1 satellite on 1 April 1960. (NASA)

This was no April Fool’s joke – the era of remote Earth imaging from space for scientific purposes had arrived. And it had taken a very short time: only two years had elapsed since the US had launched Explorer 1, its first satellite. (At this point it should be noted that the military’s Corona photographic satellites had been operational from mid-1959. However, instead of transmitting their ‘take’ to the ground by radio, they employed an intriguing means of delivering imagery by dropping film canisters in a re-entry ‘bucket’. Once in the atmosphere the ‘bucket’ deployed a chute that was intended to be snagged by an aircraft for retrieval).

Although TIROS-1 suffered a system failure in June, its initial successes were such that it was obvious that scientists had a very valuable tool with which to further their knowledge of the planet and its weather. Over 40 launches have been undertaken (not all successful) in the TIROS series since 1960, and the latest Advanced TIROS-N satellites are the basis of NOAA’s current POES system (of which more later).

Today there are many satellites from many nations orbiting Earth, able to image the planet’s surface, monitor its weather, oceans and atmosphere, and record its ever-changing nature. While all of them have other primary missions, by the nature of their sensors many can also be used to monitor and record volcanic activity. For the sake of this article, however, we shall only look at the US-led satellite and sensor programmes that are commonly referred to in connection with volcanoes, and for which imagery is easily accessible to the scientific community and general public alike.

Types of orbit

Before examining the individual satellites and sensors it is worth taking a moment to look at how satellites work with regard to their orbits. According to their mission requirements they can be placed in orbits at various altitudes from the earth, but the two most useful for our purposes are geosynchronous orbit (GSO) and low-earth orbit (LEO, up to 2,000 kilometres). There are also medium-earth orbit (MEO) satellites, such as the GPS, GLONASS, BeiDou and Galileo satnav constellations that orbit twice a day at a little over 20,000 kilometres altitude.

A stunning view provided by the GOES-12 weather satellite shows Chaiten erupting on 9 May 2008. (NOAA)

A stunning view provided by the geosynchronous GOES-12 weather satellite shows Chaiten erupting on 9 May 2008. (NOAA)

A geosynchronous orbit is one in which the satellite remains in the same location relative to a point on the earth’s surface. The simplest form is a circular geostationary orbit (GEO) in which the satellite is directly above the equator at an altitude of 35,786 kilometres, and moving in the same direction (zero inclination) and at the same angular speed as the earth’s rotation. To place a satellite in orbit where it remains constantly above a point that is NOT on the equator requires an elliptical orbit with varying altitudes, although the major axis of the ellipse must always be 42,164 kilometres.

Geosynchronous orbits have obvious applications for persistent staring surveillance of a particular section of the earth’s surface. However, they operate at vast distances from the earth’s surface, so resolution of imagery is poor, and there is some lag during the transmission of signals.

Getting down and dirty

To get imagery of a much higher resolution then a LEO satellite is the obvious choice. In terms of obtaining the highest quality of image it would be best to have the lowest orbit possible, and some short-duration military reconnaissance satellites have had the ability to make very low passes before climbing back up to a more economic operating altitude. In practical terms that means greater than 600 kilometres, with around 700 kilometres being the norm. Below 600 kilometres the satellite encounters too much drag from the gases in the upper reaches of the earth’s atmosphere to be cost-effective in a long-duration mission.

How many erupting volcanoes can you spot here? (answer at end of post!). Amazing ASTER image of Kamchatka recorded on 11 January 2013. (NASA)

How many erupting volcanoes can you spot here? (answer at end of post!). Amazing ASTER image of Kamchatka recorded on 11 January 2013. (NASA)

In a 700-kilometre LEO a satellite circumnavigates the earth in around 100 minutes, allowing it to perform around 14 orbits every day. This can be exploited in a polar orbit to provide coverage of the whole of the earth’s surface every 24 hours. In this orbit the satellite travels in a north/south direction, overflying both poles at the ‘top’ and the ‘bottom’ of its orbit (90° inclination). Meanwhile, underneath it the world just keeps on revolving around the polar axis, so that each time the satellite passes up over a certain latitude the earth beneath it has been rotating for 100 minutes. Over the course of 24 hours the satellite can build up imagery of the whole globe in 14 swathes.

This can be further exploited in a refinement called a sun-synchronous orbit (SSO). In this the orbit, with an inclination of around 95°, is timed to always pass over a certain point on the globe at exactly the same solar (local) time every day. This means that the sun’s lighting and shadow patterns will, in essence, be the same for every pass.

Yet one more refinement is the frozen orbit. As we know, the earth is not a perfect sphere but an oblate spheroid with a bulge around the middle. Gravitational forces are greater at the poles than they are at the equator. As the earth precesses from equinox to equinox so gravitational forces on the satellite subtly alter through the seasons. Furthermore, the sun and moon also exert gravitational forces on a satellite. By offsetting the inclination (to about 98°) and introducing a tiny eccentric (elliptical) dimension the satellite effectively cancels out many of these ‘perturbations’, albeit at the expense of small altitude changes during each revolution. The overall effect is a much more stable orbit, in turn requiring less manoeuvring by the satellite to maintain its station. That means less fuel burn and a longer endurance. Most of the earth-monitoring LEO satellites are in this kind of orbit.

(Phew! Hope the brain isn’t hurting too much after all that orbital mechanics. I should point out that I am a complete ‘newb’ when it comes to this so I am expecting lots of corrections. Fire away please!)

There is an excellent description of the basics of orbital mechanics here, and an insight into ‘space junk’ and the need to occasionally reposition satellites to avoid conflicts:

and a very cool (it really is!) 3D satellite tracker here:

In Part 2 we shall look at some of the satellite programmes that regularly contribute to volcanological research.

© UKViggen

ASTER photo answer: Four – from top they are Shiveluch, Bezymianny, Tolbachik and Kizimen

The image is stunning in high-resolution – you can see the lava lake and glowing lava flow at Tolbachik. Take a look at but, beware, it is a large download (8MB) and the image unzips to a whopping 200MB

Popocatépetl, seem from the International Space Station on 23 January 2001 (NASA)

Popocatépetl, seem from the International Space Station on 23 January 2001 (NASA)


78 thoughts on “Watching volcanoes from space: Part 1

  1. Norwegian Scientist Have Found an Area with Metals Worth Billions
    Researchers at the University of Bergen (UiB) has discovered hundreds of volcanoes in the deep sea around Norway, one of them is only 20m below the surface, that would be close to home for Carl.

    • Problem with underwater mining is that normally the profit is lower than the cost.
      The same valuables are also to be found in Iceland, and even then the cost is currently higher than the possible profit.
      Also, it was not in Norway itself they found it, it was around Jan Mayen north of Iceland… So the Header was a bit off.
      But thank you for the heads up!

  2. Hello UKViggen!

    A fantastic post, you must have read up like an insane beaver that has munched on Lurkings Habanero to write this post.

    Just one small detail…
    While it is true that the gravitation is a tad less at the equator than at the poles, it is only true at ground level. The difference is caused since the velocity of the rotation of the globe is highest at the equator and zero at a pole, this is creating a peripetal force outwards from the surface with its maximum at the equator. (imagine you sitting at the edge in a merry go around, if you try to stand up you are thrown off outwards, but if you stand up at the center you are not affected).

    This is not affecting you at a LEO since you are not spun around by the earths circulation. There are though as you mention loads of other forces in effect. Among them a gravitetic potential effect resulting from that bulge on the planet that you mentioned.

    • Thanks for the correction – that makes perfect sense – I know the oblation (is that a word?) of the Earth affects the orbit, but for the reason you mention. As I said, I’m a ‘newb’!

      I should have mentioned that a sun-synchronous orbit doesn’t overfly the same place every day; it actually shifts around the globe by around one degree every 24 hours thereby completing a cycle every year, in line with the Earth’s year.

  3. Diana wondered what Rn’R and playing was in the last post.
    For her edification. Rest and Relaxation while playing music with a couple of friends, after that going to a local watering hole to drink a few Sam Adams and listen to a blues band. There are worse things one can do on a sunny 28 degree afternoon.

    A side note, since it is so warm I have moved for the summer to the boat to get a bit of ocean cool. Side benefit is a short morning sail…

    • Thanks Carl 🙂 Now educated a little more and realise I need R & R 😀 Tramping round a VW Motor show dreaming of what our little rust bucket will look like in few,(many) year’s time was not R & R 😀
      We have a 1976 Devon VW Camper van bought for £900 years ago…. Now facing a complete restoration. We had a couple of good holidays but Kids and lack of finance put Her restoration very much on hold. We nearly sold her, rust and all but I pleaded that we should keep her for the future when Kids left home.
      Now the time has come. Husband is raring to go and is buying bits of rusty original Vdub
      bits . He is even having welding lessons 🙂
      Another spur to his commitment was the price of vans in far worse condition than ours 🙂 and the price of a finished VW camper is absolutely amazing : shock:

      • Sorry for the reply confusion – I thought you were talking about the VC post!

        Yeah – interesting stuff under Avachinsky. Here’s the EMSD record for last month. The swarm doesn’t show up on the depth trace as it is at around 30-36 km depth

        The big one was logged as a M3.7 on July 21. That seemed to be the start of the current swarm, although there hasn’t been anything above a M1.9 since.

        There was a similar deep swarm last week under Klyuchevskoy (in the usual spot but more intense than the usual activity), but at around 20km depth.

        • sorry about the confusion 🙂 my fault for failing to past the link – which made the original comment sound rather sarcastic

    • The choice of volcano images was purely arbitrary – NOT 🙂
      Who knows, there maybe some more in Part 2! Maybe Iceland might even make an appearance

  4. Very good post. If I may say a view from above (prenons de la hauteur, let’s take some height)! Thanks UKviggen. A good reminder of all the evolution since only 60 years or so. I think you’ll speak of the IR satellites to spot erupting volcanoes (or otherwise I have some links…)

  5. Very nice post.

    When discussing satellites and orbits, it is very easy to jump tracks and take off down one specific area of the science and loose focus on the over all picture. I had a Division Officer think that I was a bit quirky when he caught me up in combat pouring over the equations used in orbital mechanics from an ARRL handbook on amateur satellites. I was off watch (someone else was on the stack) and I was cheerfully fighting through an equation, trying to understand it.

    Today you can find most of the needed formulas in Wikipedia, with enough digging.

    The “weirdness” part of it was that I wasn’t off playing cards somewhere. I liked it up in combat. The noise level was low, and you always had an idea of what was around you by listening to the background chatter of the different watch-stations and radio circuits.

    In the satellite game, one thing that the observation targets tend to do, is to predict when they will become vulnerable to an overpass and then either move or hide what it is that they don’t want to be seen.

    For those who wish to get access to the output side of the equation… in other words, what the various sensors have seen, I recommend Giovanni.

    It’s not real time, and you have to be fairly adept at extracting data and making something usable out of it, but stuff as arcane as troposphere height, SO2 column, aerosols etc can be found there.

  6. OT…

    Got into a discussion with the wife this morning. The topic drifted to dystopian societies and their use in science (and other) fiction. I brought up a quote (likely from Niven and Pournelle) “Any society is just three missed meals from anarchy”. The conversation waned and she went to watch the teevee and I wandered off onto the Internet. I ran across an article discussing the 1859 Carrington Event, and added a quip about Fukishima’s Black Swan. Mainly pointing out that the reactors themselves actually survived the event, but the support systems did not. This yeilded the catastrophe that they are still dealing with. My point was that many such inter-dependencies exist throughout all of our cultures.

    Some how, I wound up watching James Burke Connections episode. Specifically, “The Trigger Effect.” It’s definitely one that will make you think.

    And, for the non OT part of it. It does not have to be a power system failure or a terrorist strike. Any number of volcanoes (See the world’s reaction to Eyjafjallajökull) can induce system shocks. A phrase popular with Thomas P.M. Barnett.

    Personally, I think that Barnett’s The Pentagon’s New Map presentation is fascinating. Despite the well fitting dovetail to the New World Order meme. (shit that makes the hair on the back of your neck stand on end)

    In a nutshell, everyone is connected via technology. Burke’s warnings are entirely valid. The “Human” in you should alway partake in contingency planning. It’s our strength as a species. Those who know how to grow and obtain food will have an advantage if society as a whole, collapses.

    Gloom and Doom for your Saturday musings.

    Sweden suffered a similar event in 1921

    Gurgle Translated version.

    • Here is a 2002 version of Barnett’s brief. Ignore if Global Strategy is not your interest.

      From the brief:

      Here is where I explain the 20th century in 60 seconds… pay attention. {laughter}

      People say that watching me give a presentation is like watching a farmer try and stuff 30 pounds of manure into a 10 pound bag.

      Oddball observations.

      ►No two countries with more than 100 golf courses per million people have ever gone to war in human history.

      ►You get a society to a certain level of socio-economic development they tend to get out of the violence game

      ►You get a country above 3000 dollars per capita per year, they get out of the violence business

      • ►No two countries with more than 100 golf courses per million people have ever gone to war in human history.
        Iceland is probably one of them. What the other one?

        Obviously living rich and comfortable makes populations calmer. They vote for less violent politicians as they want to keep their plentiful situation. Its when the richness is over, that populations and governments react in violent terms.This tell us that we must strive for a world where everyone thinks it is living plentiful in every aspect of human life.

        • One thing from that briefing…. Saudi Arabia’s per capita income has been declining towards that 3000 dollar per individual level for the last few years (as of the brief). The implication is that they could easily become a belligerent in the near future. They have the weapons to push their point of view, and the House of Saud came to power through force so they are not above using it to keep the status quo. They lived through the Sunni vs Shia conflict that fractured the various caliphates, and took on and wrapped themselves in the most fundamentalist version of Islam that was available…. Wahabism. This gives them the ‘moral authority’ and cemented their place in the stage of the Arabian peninsular. Having many of the holiest sites of the religion within their borders helped.

          Historically, the peoples of the peninsula have had an issue with Persian rule and influence. Bahrain was formerly a possession of Persia, and to this day has a majority Shia population. Today, it functions as a vacation spot for the area…. sort of like Vegas. (what happens there stays there). Bahrain had actually had armed conflict with the rulers of Quatar… mainly over the oil rights of the Hawar Islands. If I remember, Bahrain won the case in British Admiralty court. Having an earlier infusion of oil money and being able to afford better lawyers obviously played to their advantage.

          Today, however, Bahrain has no producing fields of any significance. Saudi Arabia donates the full production from one of the fields to the Northeast to Bahrain.

          Recently, a friend of mine clued me into a press release that the company he works for had made. He knows my background and interest in things military.

          So… along with the yammering in the press about waning US influence… you need to couch that with the declining per capita income of Saudi Arabia towards the level that tends to be willing to actually go to war.

          Iran may showboat about obliterating Israel, but Saudi Arabia IMO, sees Israel as a foil to counter ex nemesis Persia. And… they are just the sort of entity to use or allow misdirection to get you to drop your guard. Iran’s problem is not Israel or the US… it’s that looming Saudi Arabian threat that will cut off their private parts should they get too stupid.

          As for affecting Saudi Arabia’s export capability. They are not as reliant on the Straits of Hormuz as the press commonly bleats about. The former pirates that settled down and became the U.A.E. have this place called Fujairah. News from a while back indicated that some of the Emirates were getting together to put a pipeline across their peninsula to feed the terminal there. It’s capacity was stated as about 75% of the shipped flow. I found it quite funny. Leave it to ex pirates to figure out how to make money from Iran’s saber rattling. If Iran goes stupid on the straits… the U.A.E. stands to make serious bank.

          With the waning oil reserves, the Emir of Dubai has been feverishly working at making Dubai a world class modern trading center. (banking etc). With the exception of the numerous calls to prayer, you would be hard pressed to see it as any different than any modern large city.

          • What the west has always not understood is that we are an afterthought at best (maybe worst) between two different versions of Islam. All the posturing (mainly towards the US) is to get credence internally in a struggle to rule the faith.
            It is pretty much the same as happened with christianity a long time ago. We “liberated” Jerusalem as a prenup to what down the line became the 30 year war between protestantism and catholicism.

            Of all the bedfellows the US has had in that region, the familly of Saud is probably the worst. I fully understand that the Iranians hoard weapons, I would if I had the Sauds as neighbours.

          • I am gonna have to agree with you there Carl. I haven’t read a lot, but I did go through a lot of briefing documents on the history of the area. It was a convenient way to kill time while on station. The Sauds are sort of the Sun Tzu of the Middle East… spiced with a liberal dose of Niccolò Machiavelli.

          • Dubai has pretty much run out of oil and was virtually bankrupt until the al-Nahyans stepped in. Most of Dubai’s key assets, such as Emirates Airlines, are now (very quietly) owned by Abu Dhabi, which still has mucho oil. After the Brits left in 1971 there were fights along the borders between the two, and there was a very uneasy relationship which remains that way today. Meanwhile, Saudi bankrolled Sharjah, Fujairah etc to maintain a big influence in the UAE. It’s quite a shock to drive the few short miles from very permissive Dubai to the Saudi-influenced Sharjah: not a good idea to wear shorts in a public place! (not me, I hasten to add:) )

            Interesting also to note that Saudi Arabia has given Israel tacit approval to overfly its territory if it ever wanted to go bomb Bushehr or similar in Iran. Difficult not to draw parallels with ‘fiercely neutral’ Sweden tacitly allowing UK bombers to go low-level in their final run to targets around Leningrad during in the Cold War.

            • We kind of made the word “neutral” into meaning “whatever is good for us and bad for anyone against us”.
              The UAE might be one of the most odd places on the planet.

            • Well, Swedish ‘neutrality’ was, and is, nothing less than pragmatic! And why not?!
              Cost you guys a hell of a lot of money in lost arms sales in the 1970s/80s, though, which is why I suppose that ‘neutrality’ has largely been laid to rest these days.

              As for UAE, you are very right. For my sins I have had to go there twice a year since the late 1990s and have got to know Abu Dhabi, Sharjah and Dubai quite well, including the occasional shoulder-rubbing with the sheikhs. I guess I’ll just say it is an ‘interesting’ place.

      • I just have to make an observation here.
        The US fullfills all 3 of these requirements, and have done so for quite some time.
        At the same time it is the country that have participated in most wars during the last 100 years.
        I think that either the premises are dead wrong and that you get the opposite result, or that the US is a Black Swan in this regard. On the other hand you will find UK, Sweden and whole load of countries that fullfill all 3 and still go to war all the time. So it seems like the Black Swan is out fishing somewhere else on this.

        • Key point… “with each other.”

          He mentions that NATO hit Yugoslavia. And that would seem to be counter to the argument.

          On the other hand, he observes that NATO is not a country. So that would fall outside of the Axiom.

          He also notes that he had been to the McDonald’s in Belgrade and the Big Mac was horrible. So that could be another factor in it.

          My observation. The Yugoslav attack echoed the scenario presented in the movie “Wag The Dog” This movie was intended to denigrate a certain spectra of US politician as eager to use military action in and out and out fabricated war in order to cover-up or “drown out” the news of his sexual endeavors in the press. A real world twist is that the events were eerily close to the actual actions of the counter parties president.

          Even the region of the world where the war took place was nearly a dead on match.
          “Wag the Dog” → War with Albania.
          Real World → Attacks on Yugoslavia.

        • Regarding the Serbian wars, it was after all the Serbians that attacked the other, not the other way around.
          After having served in the second serbian war (Bosnia) my only opinion is that they should have been stoped sooner.

          • Eh.. I spent all my time sitting on a Cruiser outside of the Bay of Kotor in a patrol box. It was always fun watching the newer ships on station go chasing off after the ferry every week.

            As for who started what…. don’t really know. I do know that there are a shitload of pissed off people in the various enclaves.

            And the mountains around Montenegro are gorgeous. I wish I knew then what I know now about the geology. Those mountains are the remains of the supersubduction zones that used to be part of the Tethys Sea.

            The other fun part, was that we were not attached to 6th Flt. We were part of WEU forces… and followed their port schedule. 6th fleet ships would still be out on station as we were headed back to Naples or Trieste for a beer. I was riding one of these.

            That Trieste bit came in handy here a few months ago. I ran across a haughty office manager who threw out her recent trip to Venice in what appeared to me, to be a superiority move. I countered with “did she go see Maximilian’s Chateau?” (Castello di Miramare, near Trieste). “Oh, you didn’t? It’s pretty cool.”

            I had experienced issues with her on a previous occasion, and the opportunity to pop her up the side of the head with something that she had missed was a boon to me.

            Other stuff that I know from Trieste. I know that one of our drivers nearly drove off a cliff, but did manage to wind up in Slovenia by accident. And, that Disco is still alive and well there (bleh).

  7. I love the post. It is a fascinating subject. It’s amazing to think of all the preparation that goes into satellites.
    I could not find four eruptions. I counted 6 or 14, then gave up. However, I noticed that the second large feature from the top looks like a horned owl’s face emerging from darkness. The odd part is that it’s riding a surf board.

  8. And an on topic video…

    And a recollection from the past…

    In one of my operations courses, there was a NOVA movie that we used to show. I thought it was one of the more fascinating movies. We would use the movies to kill some block time (time on the podium) when the course was running ahead of schedule or we needed to work on grading or some academic issue. The name of the Movie was “Spy Machines.” This Corona movie is similar in scope. BTW, from what I understand, we had obtained permission to use it in the course. If you get a chance to see it, it gives you a bit of history of how they came about.

    As for how it applies today… well, it’s a bit dated. More info about collection networks is in the News Media than you can shake a stick at. And… an FYI for you, much of the nuts and bolts of remote sensing that is currently used on volcanoes had it’s infancy in the technology development of reconnaissance satellites. Even the vaunted Hubble Space Telescope owes a good deal of it’s lineage to the field.

  9. Yesterday and day before I went for a travel around the region of Hofsjokull and then to Skrokkalda and Haganga, and near Hamarinn and Veidivotn, and then passing by Hekla. This is my small report about it 🙂

    Always the nice volcanic trip but we catch the rather common but always somewhat crazy sandstorm, extreme wind gusts, and very cold (but thankfully no snow – we knew it was forecasted so he return back ahead of it). The weather made our trip difficult and we though it was not worth of trying our way directly to the edge of Hamarinn or Haganga; it was extremely windy and ashy. But I like those mountains as they are rather prominent and well visible from afar.

    My impression was that all dead zone region is a field with plentiful of Pleistocene ridges and tuyas and Holocene lines of volcanic hills. Eruptions seem to occur everywhere, sort of a monogenic field, let’s call them monogenic fissures and ridges. I can’t see Skrokkalda or Haganga being a central volcano. They seem the product of just one or a couple eruptions, while Hamarinn is large enough to could be considered a central volcano, and Tungnafellsjokull is also large enough to be considered a central volcano, and it has a caldera at its top. And of course the mighty ice-filled dome of Bardarbunga. From those, and to the southwest fissures occur here and there, across a vast region. There are a lot more of hills just similar to Skrokkalda, Skrokkalda just is the only one with a SIL station on its top, we saw it from afar, but the track leading to it had a “just for staff” sign and so we did not went there. I did not want to cause a tremor myself and cause a stir in volcanocafe 😉 Anyways its quite a clever position to have a SIL but personally I would place it further south and i will tell you why.

    It seems older eruptions were the ones at Skrokkalda or Haganga (Pleistocene), while the newest eruptions occurred further south, around Veidivotn (870, 1477 eruptions) or Trollagigar (the eruptions of 1862). I wonder if this is a trend or not. However, Pleistocene ridges also occur further south, like alongside the Langsjór lake.

    To which volcano each ridge belongs is a matter of guess, and as Carl posted (Laki), it is my opinion too, that these eruptions come from a source of magma independent from what it is thought to be a central volcano.

    I also found some evidence of what seemed to be pumice around that region, but little; mostly tiny whitish volcanic gravel but the weather was nasty when I found it and I just returned quickly to the jeep. Mostly, black basalt is everywhere across that region and it seems it is gas-rich (lots of holes in those volcanic rocks).

    Hofsjokull surprises me because it poses such a large caldera, and it displays evidence of recent early Holocene eruptions to its southeast (and also southwest) side. I would love to have gone closer to it, but the glacier is surrounded by outgoing rivers and seems almost impossible to drive or hike over there, without expert help (furthermore off-road driving is strictly forbidden). Anyways the official tracks can still be quite challenging to drive. It is quite an astonishing beautiful volcano.

  10. Curious, do we have any resident experts on mt. Fuji? I know Fuji is subject to a lot of tabloidism in Japan, but it’s definitely worthy of discussion due to nearby population, the overall height of the edifice, and the unique nature of the area in which it lies. I would be very much interested in learning more about the volcano in general.

    Considering that it’s perhaps the second most famous volcano in the world, I think it’s surprising there has not been a post on it yet.

    From what I know –

    It sits on top of a Triple Junction, which by itself is rather unique. There aren’t many volcanoes that sit over triple junctions in the world, and I believe most of those that do are not stratovolcanoes. How does this affect volcanism in the area?

    It’s last eruption, a VEI-5 in the early 1700’s erupted from a new flank vents, forming a large crater on the southeast edge. Does this mean that the central vent has likely been plugged and the volcano has effectively lost the ability to relieve pressure? Or is this normal behavior for the vocano?

    • Sadly I am not that good at Mt Fuji.

      But, I am fairly good at tripple-junctions. At almost any tripple junction where there is active volcanism you will find an active volcano smack ontop of it.
      Iceland for instance have several tripple junctions, and ontop of them you have a volcano. Currently there are Hengill, Bargarbunga and Theistareykjarbunga.
      Now Iceland is a hotspot volcanic area and Japan is a subduction melt driven volcanic area. But, you only have to wander off up to the Kamchatkas and you find a volcano on a tripplejunction, same goes for Phllippines and Indonesia.
      In Guatemala you have both Amatitlan and Atitlan on tripple junctions.

    • It may be dormant. It isn’t going to erupt in the near future. It is probably normal. The magma may have just found another way to the surface. The GVP says that there was flank eruptions before.

  11. Been watching the Okeanos exploring the Mytilus Seamount off the New England coast. While everyone on the ship is “ga ga” over the different species of coral and sponges, I am awed by the rocks. Volcano Cafe – I am doomed! Seriously, it’s just layer upon layer upon layer of what I would describe as rubble. Doesn’t look like lava flow or pillow lava. Just rubble.

      • Looks like fairly typical basalt. Old, worn and fractured, but still fairly standard old sea floor basalt.
        As the seamount was built there was boulders produced of pillow lava, the pillow lavas has rolled downslope and fractured giveing that rubbly feel

        • Yes, this looks like pillow lava now, but there have been some areas where the whole scarp looks like it is a build up of small rubble. Makes you wonder what on earth is holding it up. Thanks for looking.

          • It is rubble that have slid downhill that probably was your rubble field.
            I just head them saying that the saw their first pillow lava for the day. That is not true though, they passed over several pillows before that they did not notice due to looking at animals and stuff.

          • Yeah.. .but the fun part is the New England hotspot. Allegedly this seamount formed as the area passed over it. But right now… that hotspot is on the other side of the MAR.

            Hotspots are supposedly, mostly fixed with relation to the core and mantle. How did the MAR get on the other side of it?

            That sort of points to both the North American and African Plates moving towards the west as a unit, or a much more mobile hotspot.

            How I reconcile this… a hotspot is just the surface manifestation of a sheet like plume of material wafting up like hot taffy.

            • The Iceland Hotspot is for most points and purposes almost on the other side of the MAR. The MAR is moving west in relation to the core/mantle boundary. Or more to the point, the core/mantle boundary rotates to the east.

            • The Great Meteor hotspot it is now known. It formed Great Meteor seamount most recently 10 million years ago. That thing is giant.

            • The New England Hotspot eventually moved east and formed the Great Meteor Seamount where it is found today – to the south of the Azores. Only took 100 million years or so.

            • It made a seamount chain. Great meteor seamount is 10 million years old. It is 50×28 km. I wonder what the current state of the hotspot is.

  12. I wonder if given enough time this hotspot would eventually end up back where it was. Something to ponder.

  13. As I made my nightly check of the moringcables I had a late night cup of hot chocolate looking up at the stars above. I sat there pondering which will be the next volcanic eruption to captivate us. I guess that time will tell in the end.
    Now I am off to sleep, nothing makes me sleep as well as a gently rocking boat.
    A good night to all!

      • Going over a sand shoal in waves might not be the best of ideas… They must have been aching for a beer pretty bad to try a run into port over a sand shoal in those conditions.

      • Could be the difference between hard or soft aground….

        (For others: soft aground, the vessel can get itself afloat again by waiting for a shift in the tide or moving the ballast around, hard aground, you need outside help)

        Some incidents are so funny that all you can do is laugh. (such as loosing your rudder at midnight steering checks (fell off), or wrapping a sonar tail around a reef.)

        By far, the funniest thing that I have seen… was when a steam powered ship was lighting off boilers in port, and generated a thick, greasy black plume of smoke that then drifted across the harbor onto the quarterdeck of a pristine gas turbine vessel… leaving the deck watch in their gleaming summer whites, speckled with little black dots.

        When lighting fires, the combustion conditions may not be ideal and incomplete combustion is quite common until the plant operator can get a handle on the boiler conditions. (speed of the forced draft blowers and the fuel feed rate)

        The beauty of a steam ship with boilers, is that you can use almost any flammable liquid as fuel. On one of my ships, we carried fuel for other vessels. A load of JP-5 got contaminated and had to be decertifed for flight use. Rather than take it back for disposal, we ran it through the dewatering tanks and burned it as Bunker Fuel Marine. It made good steam and saved money. 😀 (the fact that it got contaminated wasted money, but it made a bad situation less bad)

  14. I think a Dalek should be the follow on…

    BTW… the drive signal to the coil controls the tone that the arc will yeild.

    For other oddities, you can actually make a flame into a “speaker” by passing it through a modulated electrostatic field that causes the ionized particles to vibrate.

    ► ► ► WARNING ◄ ◄ ◄ Telsa coils are inherently dangerous. The performer in the video is fully shielded. (including his face, inside a tightly woven metal mesh). Lethal Voltages are generally present. If the driving frequency for the coil drops low enough, it can cause internal injury if the current passes through your body. DO NOT ATTEMPT TO MESS AROUND WITH TESLA COILS UNLESS YOU FULLY UNDERSTAND THE HAZARDS AND THE NATURE OF ELECTRICITY. (even then you could get the shit knocked out of you. Trust me, that ain’t no fun.)

    Additionally, an arc of electricity does produce RF energy. This could interfere with electric equipment, and may place you in violation of the rules and regulations for your country.

  15. Many thanks UKViggen. I have often watched satellites (When we have had a cloudless night) and wondered. OK the wondering was brief as my thoughts ran into overdrive when thinking about the hows and whys and as everyone on here knows Physics and Maths are not my stronger points.
    I found this post incredibly enlightening and I actually understood it: Yayyy! UKviggen has succeeded in getting me into Physics 😀
    Does anyone else have the problem I have of drifting onto another tack when watching a posted link or Video Clip ? watching Lurking’s clip of the boat in rough seas and off I went back to 1968 and the heaving deck of TSS Golfito between UK and Jamaica,with an overnight stop in Port of Spain ,Trinidad. I found a clip of her sister ship TSS Camito on youtube… I wont post it as it resembles no way the hellish 12 day voyage we had….Lifeboat didn’t work. Small swimming pool on deck started loosing water over one side….trouble with the bilges evidently caused a severe list. Ship’s doctor was a drunk. Captain was seasick for first 24 hours. Nothing to watch for 12 days except more sea and Sargasso weed and of course the waves….very, very , very large waves. Scary waves. I will never, ever, book a cruise holiday. Not the waves fault, purely the feeling of being confined in a small area on a huge sea with no safe way of escape.
    Evidently we were sailing on the tail ends of a hurricane or two.
    PS I wasn’t actually seasick… I was beyond that with fear 😯

  16. @ Irpsit. I read your description of your walk and A) I felt very jealous and B) I too would love a post with some pictures. Thank you. I love your first hand accounts. 🙂

    • Diana, you should come to Iceland for holidays. Then you can visit several of the volcanoes for yourself, watch northern lights, see the lava fields of Laki, etc… 🙂
      The flights from the UK can be quite cheap. Iceland Express or EasyJet.

      Carl: I could not find any reply from you. Are you sure you mail me at the correct address?

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