14 comments on “3 + 2 Volcanoes: São Miguel Island, Azores

  1. In Ecuador: since 26/2 Tungurahua eruption had began intensifying and its alert level was raised to orange. Over the weekend spectacular pictures appeared on the internet, and since yesterday IGEPN issue instant warnings about new explosions and pyroclastic flows every few hours. Because of strong ash fall, relocation of livestock has been recommended. An accumulation of ash of 7.7 kg/m2 has been recorded since Febr. 26.

    I cross my fingers for the people in the communities at the foot of the volcano!


  2. Nicaragua: In the Masaya crater are now three crater lakes active and a fourth vent forming in the SE part of the crater floor.


  3. Howdy Granyia – Interesting writeup. I am used to most of these oceanic hotspot volcanoes to be effusive in nature with caldera formation via subsidence. Appears this island has an appreciable percentage of ash-rich volcanism. I wonder what makes the difference in the magma source.

    Had the opportunity to fly into Lajes AB on Terceira Island nearly 30 years ago. Spent half a day there and ate a nice local meal in a small place half way around the island. Great wines. Cheers –


    • The abundance of ash deposits makes sense when you remember there were Plinian phreato-magmatic eruptions, submarine and/or through big crater lakes. What makes Plinian eruptions? High content of gases like water in the magma. Is this where the MAR volcanism comes into it? Compare Hawaii – no rift zone, no highly explosive eruptions. Compare Iceland, hotspot with MAR – lots of ash with Eyja and Grimsvötn.


    • What leaves me more puzzled is the dominant occurrence of trachytes. If I understand right, these were more evolved magmas, meaning they must have remained for long periods in some reservoirs below, re-heated and depleted of mafic minerals before eruption. So where has it been for so long and why? Is that the same process now happening at the Congro fissure zone, Basalt rising but not erupting, staying somewhere below and evolving into Trachyte?


  4. You should do an article on the Newberry volcano and the craters of the moon volcanic field. 🙂 Also, don’t forget about the other Azore islands. 😉


    • Howdy Nova – Great minds must think alike. I have been thinking about Craters of the Moon, Idaho. We have a few posts in the queue. Thanks for the suggestions. You know, we are always looking for posts from interested folks. Should you want to do one or the other, I expect it would be a great read. What do you think? Cheers –


  5. Pingback: Visiting Furnas: an Azorean village inside a volcano! | Middle Europe

  6. Pingback: Very shallow minor earthquake swarm below Sao Miguel, Azores Islands, Portugal - February 12, 2018

  7. Hello,
    I am doing research on the ancient Vulcanism of the islands. There are many questions that I would like to ask but perhaps you can just point me in the right direction for further questions. My current train of inquiry deals with possible locations of collapsed, underwater, lava tubes just east of Sao Miguel. No more than 2 km from the eastern shore line. I’ve used some gravitational and Bythometric charts and have spotted some peculiar formations off the coast (some 200-500m) of Ponte Sossego. Please contact me if you can.



  8. Was in the Azores about 30-35yr ago at Lajes AB and recalled seeing a house, which I’m sure was only visible from the air, right in the centre of a dormant (I hope) volcanic crater. Complete with a green yard and all that. We almost couldn’t believe this and in fact circled it several times until we realised we could be becoming a nuisance. Well, it did seem a curious outfit. Who on earth would pitch a home in a place like that?
    Don’t recall which of the islands it was on and didn’t recognise it anywhere on your post.
    As we were there on active duty we didn’t exactly have much time for further enquiry. . This leaves the question of this curiosity unanswered.
    Are you able to research this and/or shed any light on the subject? Perhaps in a future post?
    My story’s credibility could only benefit.
    Thank you,
    Larry J. Vargo, USNR


  9. Hello,

    I just read your post about the 3+2 vulcanos on S.Miguel in Azores. I am a native Azorean from S.Miguel with a keen interest in vulcanology and really enjoyed your article.
    It was very informative and complement what we learnt at school on our geology classes about the island.
    I just wanted to drop a comment to let you know that the people that died on the hot pools in Furnas died because they fell in them, not because of the gases. It was only in recent years that barriers have been put around the hot water pools and unfortunately, many years ago, some people fell in them by accident (some of them children) and most were not able to survive the burns they sustained.


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