The Bogoslof eruption

Castle Rock in 1947 (AVO).

Castle Rock in 1947 (AVO)

Volcanoes are the tip of an iceberg. 90% of the volcano is hidden, down to the magma chamber 10 km or more below the surface. What we see is only the cone on top of the conduit. The perfect cone of Fuji, or even St Helens (before it blew up), is like the hat on top. What lies below the hat is concealed to the eye. But for some volcanoes, not even the hat is fully revealed. Sometimes most of the hat is under water, and only the tip of the hat peaks out above the surface. Most of the Hawaiian volcanoes are like that. And so are some in Alaska.

Bogoslof Island was in the news this week for repeated, unexpected eruptions. It is one of those largely-submarine volcanoes, which peak only a little above the water. And that little is constantly changing.

Location of Bogoslof Island (AVO)

Location of Bogoslof Island (AVO)

Bogoslof is one (and sometimes two or three) of around 70 Aleutian Islands, part of possibly the most obvious volcanic arc on Earth. The Aleutian arc links Kamchatka to Alaska. All the islands are volcanic in origin. Here the Pacific Ocean meets the Bering Sea in a titanic collision. The run-in happens at about 7cm per year with the Pacific plate the subducting one.

The pre-eruption island (wikipedia). Click on the image for full resolution.

The pre-eruption island (wikipedia). The camera is looking to the south. The dome at the front is from the previous eruption, in 1992. Click on the image for full resolution.

Bogoslof Island is just north of the main arc, sometimes considered part of a back-arc. It is at the same latitude as Edinburgh, so not as far north as you could be imagined. It is cold, though, with temperatures rarely above 20 C and average temperatures in winter near freezing. Rain happens on most days. The island is not large. The surface area is less than 1 km2, and the highest point no more than 150 meter above sea. It is the tip of a submarine volcano, desperately trying to get above water but every time an eruption raises the peak, wave erosion reduces it again. But it has managed to keep its head above water, so it may be destined for great things. Just give it time. Submarine volcanoes grow normally until they reach the water surface, where erosion is suddenly much more severe: a flat-topped mountain develops, limited in height by wave action, until the island reaches a large peak well above the high water line where erosion again becomes less. Below the surface, the mountain of Bogoslof is about 2 km tall, so indeed about 10% of the height (but much less of the volume) is above water.

The island reportedly emerged above water during an eruption in 1796; at the time this was Russian. However, it clearly is older than that. An island appears (unnamed) on a map from 1768, much smaller than Bogoslof but at the same position. It was also on Captain Cook’s maps of 1778. Wikipedia reports eruptions in 1796-1804, 1806-1823, 1883-1895, 1906, 1907, 1909-1910, 1926-1928, and 1992. Now 2016 should be added to this list. It is not always the same point: sometimes eruptions come from next to the visible island. But it is always the same volcano. The youth and instability explain why the island remains uninhabited.

A minor, steep fault runs across the island. The northwest side has dropped by 1.5 meter. Between 1927 and 1934, the region around the fault near the lagoon appears to have been uplifted by 15 meter. It is not just the eruptions that build these islands. The uplift from accumulating magma is more important.

Each eruption changes the island. The map below shows the outline as it was around the second world war, surveyed by the US department of war. Castle Rock, the steeple seen in the photo, is the remnant of the dome extruded in 1796, also called Old Bogoslof. 500 meter away is a second island, Fire Island, remnant of another eruption. It is tiny, and lost half its size between 1935 and 1947. At one time it was the largest of the two. The maps below show the development of the island, with panel A from 1768 and panel I from 1947. At times there were three separate islands. Ship Rock (called Sail Rock at the time ships still had sails) mostly collapsed in 1890. The 1992 eruption occurred at the north end of the island and changed the map considerably over there.

Map of Bogoslof  from 1947 (AVO)

Map of Bogoslof from 1947 (AVO)

Changes in Bogoslof Island between 1768 (panel A) and 1947 (panel I). B: 1796; C: 1889; D:1895; E: 1906; F: 1907; G: 1922;  H: 1936.  The dome south of Ship Rock is known as Old Bogoslof, and the island to the north is New Bogoslof (now reduced to Fire Island).

Changes in Bogoslof Island between 1768 (panel A) and 1947 (panel I). B: 1796; C: 1889; D:1895; E: 1906; F: 1907; G: 1922; H: 1936. The dome south of Ship Rock is known as Old Bogoslof, and the island to the north is New Bogoslof (now reduced to Fire Island).

The current eruption started on Dec 20, 2016 (Tuesday). There is no monitoring equipment on the island and the eruption was first spotted from the air. A second eruption occurred on the next day, detected by satellite, and strong seismic activity was followed by a third explosion on Friday. The wind was blowing the ash and sulphur to the north, away from inhabited areas. The eruptions were brief, with the one on Friday lasting for just over an hour. The ash clouds caused a lot of lightning and this has been detected (there are no reports whether it was detected from New Zealand, as in the case of nearby Okmok). There was yet another explosion on Monday. Each explosion caused an ash cloud to some 10 km height, similar to the previous eruption in 1992. The eruption that year lasted for 2.5 week, and if the current activity is similar there may still be some more explosions.

The eruptions have quickly redrawn the map of Bogoslof Island. The map below shows the immediate changes. The dashed line shows the shore line as it was a year ago. The eruption site appears to have been at the shoreline, not far from where it intersects the fault line. It is almost the exact position where a Navy hut had been erected during the war. The area around this site has collapsed below water, whilst the ejecta created new land further out. One possibility is that the eruption will eventually create a lava dome at the central location, and will enlarge the overall island. At least until erosion tries to even things again. Bogoslof is in a fight with the waves, and the outcome is not yet certain.

The new shoreline of Bogoslof Island (white line) superposed on an image from  2015. The explosion has pushed a large fraction of the island back underneath the sea, possibly temporarily.

The new shore line of Bogoslof Island (white line) superposed on an image from 2015. The explosion has pushed a large fraction of the island back underneath the sea, possibly temporarily.

Bogoslof Island is important for wildlife, with populations of several thousand Stellar sea lions and northern fur seals (both declining), and close to 100,000 sea birds including guillemots, tufted puppins, a small number of pelagic and red-faced cormorants, and two kinds of kittiwakes. the current eruption will not directly affect these as it is now winter, but the changes in the appearance of the island will have an impact, which could be either positive or negative. It will be interesting to monitor the wildlife over the coming summer. The birds and seals may enjoy the still-warm ash.

Tufted Puffin on Bogoslof Island. Click for full resolution.

Tufted Puffin on Bogoslof Island. Click for full resolution.

87 thoughts on “The Bogoslof eruption

  1. Nice article, about a location I didn’t know anything about.

    There’s a typo just above the pic of the puffin “eruption will nor directly affect “

  2. Thanks, Albert, for doing the research and sharing it. Where can we go to keep current on the developments there?

  3. Just noticed that Nevada was trending locally on twitter. Reports of a 5.8 quake Near Hawthorn. This quake seems to be widely felt in N. Central California, As far away as Fresno.

    What comes to mind is that this is on the Nevada Side not too far from the Long Valley Caldera.

    Also is there a way to change the Avatar on these posts?

    • Next to Aurora crater. It is a geothermal area, lots of faults. No recent volcanic activity unless you call 8 million year ago ‘recent’. The quake is too deep to have bene caused by drilling so probably just one of the many faults has given way.

    • Click on your Gravatar, then in the upper right hand corner you should be able to sign in to WordPress, I get signed in automatically, you can pick any picture you want.

      • I am already signed into word press. Clicking on the gravatar only takes me to the gravatar website. I do not have an account on the gravitar site. I checked and that site does not seem to be better more sheepish generic ones. Usually I just upload an avatar or link to one on my own site(s) (which have wordpress content.) Having a gravatar account just seemed redundant.

        • I get to, on top is a black band with my e-mail and avatar, right upper hand, there I can change anything I want. When you click on your avatar, do you get sent somewhere else? I know there may be other ways to use WordPress.
          I am commenting using my wordpress account, what does it say when you comment?

  4. Is this swarm unusual the earthquakes are happening every couple of minutes is this usual for this area ?

  5. In Iceland, deep driling project has now reached 4.6 km in Reykjanes. This is the second attempt of the project, after in 2009 they drilled 3km in Krafla and hit the magma chamber, creating the first manmade volcanic eruption (but extremely tiny).

    The group will hit the final 5km next week, and if sucessful is going to be the first supercritical steam geothermal borehole plant in the world, which will produce much more energy than before.

    After this they plan to drill deep also in Hengill in 2020.

  6. HorrorDay Inn.

    Yeah, I said that. I’ve been hit with card fraud before {probably elsewhere} and it pisses me off to no end. If they don’t fix this, they deserve to loose revenue. They are not all that special, I’ve done just as well sleeping in a truck.

    If anyone reading this is upset that I negatively endorsed them, get over it. In my experience my comment is dead on accurate. They think too highly of themselves and per the linked article, you are putting your wallet at risk if you stay there.

    • 100%- got my bank card account cleaned out when stayed there
      in ’15 …

    • KCRA. A “news” site. Everything is a catastrophe to a “news” site so they can keep their readership up. Can’t sell advertising unless you keep people glued to your “news.”

      Point of fact, this is in the Walker Lane region, and Walker Lane accommodates somewhere between 10 to 18% of the relative motion that the San Andreas doesn’t accommodate. As for precursors, well, quakes are precursors/indicators to everything moving about the surface of the earth. The question is how much of a lead time do you have?

  7. In regards to wildlife being affected on Bogoslof. I’m willing to place money on the tufted puffins being negativly affected by this eruption, at the minimum for one breeding season.
    Puffins need to dig burrows for their nests in loose soil (sometimes being under a rock is good enough, but this is far from the majority). They can probably dig in fine ash, but I’m quiestioning the stability of relativly newly erupted ash, and digging around in small pebbles/rocks to make a burrow is probably out of the question.
    That is, if the islands isn’t covered by hardened lava, in which case it definitely will have a negative effect on them.

    The other birds will most likely not be overly affected by the eruption.
    Kittiwakes generally favour very steep rockfaces where they can build their nests, so depending on the layout of the island after the eruption, they may suffer a bit or even benefit.
    The guillemots and cormorants will probably accept any topografic changes without too much of a hassle.

    • Indeed, puffins prefer burrows which must have been in short supply on Bogoslof at the best of times. Tufted puffins will use crevices or rock piles if no burrows are available but these may be more open to predation. You are probably right with your expectation.

  8. Strange – Öræfajökull was very close to having a very shallow green star. Perhaps it is jealous of Katla?

    30.12.2016 03:33:58 63.992 -16.599 0.5 km 2.9 99.0 4.8 km ESE of Hvannadalshnjúkur

    • 2.9 mag quake at .5 kilometer depth almost directly below the summit.

          • Sorry, maybe I’ve misunderstood you. We’re multilingual on here, though we use English as our first language, and that can put non-native speakers at a disadvantage: So, Yes, “Ray” if the journalist is speaking German.

          • Get it? Yes, I think so:
            If my understanding of Icelandic is correct, “æ” is pronounced as in “aisle”, as in “rye”, or “ray” as pronounced by a German speaker but *not* as in “ray” as pronounced by an English speaker.

          • Oh right, didn’t know that! Somehow I think the media would “accidentally” overlook that fact, so it still kind of works…. I think. 😀
            I can’t say I’ve ever unintentionally spoken German before 😛

            Maybe a more likely media name would be Mount We’re-All-Gonna-Die-Doooom!!

      • By the way, does anyone know what’s happened to the Icelandic drumplots? Almost all of them stopped updating on Christmas day and there’s just a handful still running (none of the really interesting ones).

  9. Bogoslof did it again, back at code red. From:

    An ash-producing eruption started at 23:45 Dec 29 AKST (08:45 Dec 30 UTC) and is continuing as recorded by seismic data on nearby islands and as seen in recent satellite images. Cloud-top temperatures from satellite suggest a cloud height of around 20,000 ft asl. Regional winds are from the southwest. We are raising the Aviation Color Code to RED and the Alert Level to WARNING.

  10. Oraefajokull M2.9 today, almost a green star!
    This volcano is definitively awakening, after years without a single earthquake.

    Oraefajokull is a *massive* volcano. The tallest in Iceland and one of the largest, with a crater about 5km wide atop 2000 meters. A beautiful candidate for a new Icelandic caldera.

    The 1362 eruption was a VEI6 (10km3 rhyolitic tephra), and perhaps the most violent eruption in Icelandic history, since settlement. Later a VEI4+ eruption occurred in 1727. Both started and finished rather suddently, with large glacial floods and several deaths.

    This is a dangerous volcano, poorly understood, poorly moninored and little known by most here in the blog.

    I have been thinking that, with increasing Icelandic hotspot reaching for a peak in activity in the next two decades, this volcano could even see another big eruption.

      • Two quakes actually. Largest has been revised to M2.6. A second M1.3. Both shallow. Smaller quakes might have happened and not recorded due to lack of detection stations nearby.

        A larger swarm occurred also in the rhyolitic Torfajokull. A M2.7 followed by several smaller earthquakes. Also shallow.

      • The takeaway…

        Full evacuation of the outburst flood hazard areas can not be done in under 30 minutes, and outburst floods take 20 to 30 minutes to reach the lowlands.

        • The situation is peculiar. There is not so much place to live around the volcano. South and east of it, the coastline is very near the glacier and the mountains (and the coast is very flat so it forbids any shipping activity), west of it, we have sand wastelands (and sinking sand) laid by Grimsvotn glacial floods, north of it you have the ice cap of Vatnajokull.

          The population can only live sandwiched between the narrow coastline and the ice capped volcanic mountains. Really just by the slopes of Oraefajokull, otherwise you are in the flood plains and sand wastelands. The great thing is that the climate there is the mildest you can get in Iceland. Before 1362 eruption, there were many settlements, all killed and abandoned. Nowadays just a few farms and tourists guesthouses.

          Of course, any glacial flood from this volcano reaches the farms in less than 20 minutes.

  11. In case someone, like me, is interested in both Astronomy and Volcanoes Astronomy Cast did a live show about Olympus Mons yesterday.
    Skip to 11:00 to go directly to the subject (or listen in to Pamela and Fraser intro to the show).

      • Plus one second: there is a leap second which for the UK is at the stroke of midnight. Means this year is one second longer. As it was also a leap year, we got both an extra day and an extra second. (In time zone to the east of the UK, the leap second occurs during 2017, so they have a shorter year, and to the west, the leap second happens before midnight). Mind you, given a choice this is not a year I would want to last any longer. It was the year of living dangerously. Perhaps it will be remembered as the year China took over as the leader of the free world. Or the year Russia won the US election (presumably they will be disqualified later for using doping). Or the year Great Britain became Little England. Or the year that volcanoes refused to join the eruption game. Cheers!

  12. And talking about 2016, VC lost Sissel Kramstad, one of the founders of VC. It is worth raising a glass to her memory.

    And in contrast, what was your favourite VC moment of the year? Any post or comment you liked best? Ian’s movie plots? Carl’s mammoth guide? Henrik’s tour de force of Olympus Mons? Hobbs’ volcano overviews? Kamchatka’s wonderland and South Sandwich mysteries? I personally enjoyed all of those immensely.

    • I loved all the items mentioned above, but for me Ian’s plots were the highlight.

      So lovely and informative to watch.

      Can’t imagine how much work must have gone into them, and all of the other contributions. I’m both impressed, humbled and grateful, for all the effort that people put in to make this such a great site.

      Happy New Year everyone.

    • Personally, and not sucking up, I liked your 3 Chapter posts about Pluto, Charon and their geology the best!

      Cheers to all contributors to this lovely café!

      • Maybe your astronomy interest shows .. Of my own posts, the sale of Yellowstone was the most fun to write, trying to April-fool everyone across the political spectrum. And I am proud (if I can say that of my own work) of the Calanais post.

        A happy 2017 to everyone!

  13. Saturday
    31.12.2016 17:31:17 64.674 -17.461 6.6 km 3.9 99.0 4.9 km NE of Bárðarbunga

    • Saturday
      31.12.2016 17:46:00 64.670 -17.420 8.6 km 3.6 99.0 6.1 km ENE of Bárðarbunga

      31.12.2016 17:35:22 64.668 -17.460 4.2 km 3.3 99.0 4.4 km NE of Bárðarbunga
      31.12.2016 17:31:17 64.674 -17.461 6.6 km 3.9 99.0 4.9 km NE of Bárðarbunga

  14. All the best for you, VC readers & contributors, happy 2017 and lots of health!

  15. Happy New year (3:30) to go here . Cold -15C windy and snow in the Forecast. Warm fire, Springer snoring, Poodle wedged between wife and I
    listening to Leonard Cohen, among others.

    • Nice! I watched Purple Rain, trying to block out the fireworks that are totally out of control, luckily horses and dogs seem to be okay.

      • Spend the night in the company of two of our horses. They were literally shitting themselves from fear. Same thing every year..
        I can imagine how tough it must be for Icelandic horses and owners, when they are effected from an eruption..

  16. Happy New Year! Here’s to 2017 – a year of spectacular eruptions that harm no-one…

  17. And Happy New Year or Blwyddyn Newydd Dda from Wales – here’s to an exciting but well risk-assessed 2017

  18. Albert, 2016, the year that England became little England, Russia won the US election and etc…. What will 2017 be?

    Well, historically major social changes usually happen in highly charged decades of change, then followed by many other decades of peace and calm. We are just progressing into one of such highly charged historical periods. So its expectable that many dramatic events happen.

    I think 2017 will only bring a continuity of 2016. One would be foolish to expect 2017 to be a calmer year. The collective moods are highly charged and angry, so this creates fertile ground for more big events.

    Likewise in Iceland, hotspot activity follows also a similar pattern. Decades of intense hotspot activity followed by many decades of calm, with relatively little eruption frequency. We just entered one such period in Iceland too. Such periods have occurred in the late 19th century, in the late 18th century and in the early 18th century. As far as we are aware, only the Icelandic hotspot seems to behave in such cyclical manner, others do not.

    Very funny that now – both an increased decade of human change and Icelandic hotspot activity – seem to have kicked in almost at same time; one started in 2008, and Icelandic hotspot activity seems to have started around 2011. What a decade!

    I wish a 2017 calm worldwide, despite the trend…

  19. Having clicked through the entire year, I found many really good articles, but the one I remembered enjoying most was the selling of Yellowstone, as I managed to get quite a few people to see red by sharing it on fb.

  20. Happy New Year from San Diego. Can’t think of any of the articles in 2016 that I didn’t enjoy. I’m continually amazed by the volunteer effort by all the contributors. I find that after every article that I am inspired to dig more and would never had gone down that path without the article.. Looking forward to more in 2017!

    Here’s moon-over-Momotobo tonight:

  21. Well, my New Year wasn’t so happy. Today my old Springer, Rollie, died.
    he was having some (we thought) minor breathing issues, and we had just
    visited the Vet Friday. He kept wife and I up all night with this cough. That suddenly worsened. He died in my arms.. Got to tell him I loved him….
    I will miss that big black rubbery nose and those long ears and soulful eyes,
    He was a black and white Springer. Scots bloodlines, from a Highland
    breeder his bloodline came from to Oregon. He will be buried in in a Hunting
    Stuart tartan wool blanket….
    His favorite..
    Too bad I can’t afford a Piper…

    • So sorry for your loss. Had an American Eskimo (dog breed, not a person) that had progressively worsening seisures. A bit of a jerk, until he came to terms with me. Very loyal after that. Similar departure. It never gets easy. All you can console yourself with is that the misery is over for them and they can run and frolic in the great beyond.

    • And yes, I beleive dogs have souls. After all, they domesticated humans about 34,000 years ago. They must have seen something useful in us.

  22. And to start the year, an M4.5 in Lake Baikal. Not particularly unusual, but interesting

Comments are closed.