36 comments on “Piton de la Fournaise – review of the Eruption in Réunion

  1. Great article, Granyia. Based on what I read and what I saw in the video, I’ll go out on a branch and predict that this will erupt again some day.


  2. Very nice article Granyia

    La Réunion island shows some older and eroded vocanoes (to the north of the island) – they gave birth to very impressive scenery (Cirque de Mafate) which are a paradise to hikers.
    The piton de la Fournaise (meaning furnace) is very active. This time it seems the eruption was quite short. On one side of the volcano, up to the shore the land is empty. It is the “Grand Brulé” – great burned space.The volcano is very well monitored and the authorities forbade acess to the volcano a few days before the eruption as the seismic activity was ramping up.


      • Indeed, for the first time since august 2014 there is now no stars on the Iceland seismic map on the IMO site.. The seismic part of this event seems to be tapering off markedly – will be interesting to see if the magma will stop flowing after subsedience stops… The activity in the dike seems to be fairly unchanged the last couple of months.

        Congrats on the new blog btw and interesting articles! 🙂


      • I think you misread scale 🙂

        Nope, we’re officially starless as of now. In fact, there’s nothing stronger than a 1.7

        Do we end with a whimper, or a bang? Or maybe we haven’t ended at all; maybe the caldera floor has just hit rock bottom, but the magma inflow from deep will continue largely unaffected.


    • Actually, the horizontal GPS measurements look like there might be some slight inflation at Bardarbunga. This is also an indication that the eruption may be ending.


  3. Bravissima, Granyia! 🙂
    How about the theories connecting the Reunion hotspot to the Deccan traps? Are they still valid? If that is the case we can expect a lot more coming from Piton…


  4. Subsidence in Bard has stopped and even maybe started to reverse. this scenario was previously postulated by Jon and others to lead to a major caldera event. What is the opinion now among the more experienced in this site? Also, after 6 months of heavy seismic activity, could the ground be so fractured that no mor high energy quakes are needed or even possible when the region is kneeled by tectonics or magma movement? Like floating crushed ice compared to a solid ice sheet! what do you think?


    • Well, originally I thought that this would be Hawaii-like, with the caldera subsiding and the flank flow ending when the magma ran out. Then I saw that it could be Askja-like, with an eventual collapse of the caldera lid, leading to a violent caldera eruption. The flows have been subsiding at Holuhraun for a while, and the rate of caldera subsidence has concurrently slowed.
      In order to have a violent caldera-forming eruption, the roof must entirely collapse, exposing the magma chamber, or it must be blown completely off. Neither of these appear to be happening at the moment. Therefore, I suspect this eruption will simply peter out. Slow inflation actually may signal the end. Grimsvotn, for example, began inflating as soon as its eruption ended.


      • This isn’t entirely the case.

        If a large enough crack is opened, it could potentially depressurize the magma chamber, allowing the pressure to release. Also, there is potential for melt-water from the glacier to enter into the magma chamber through one of these destabilized cracks – henceforth resulting in a phreatic detonation, which may lead to more water, more depressurization, and so forth.

        A caldera’s roof collapsing can only occur after the magma has left the chamber – the caldera eruption doesn’t necessarily happen as a result of that happening (Although there is typically a very large ignimbrite that comes as the collapse occurs).


  5. Thanks for explanation! I do not know what is ignimbrite, links to read more?
    Last 2 +4 quakes gave very different results on the icecap as judged by the gps readings. Why? The latter was much more shallow giving and was followed by a temporal rise of the gps station…..


  6. The SW to NE trending portion of the dyke looks like it is starting to build up some pressure, if one can look at the EQs along its path as an indicator. They’ve been there throughout the episode, but in the last couple of days that line on the IMO map (of EQs) is starting to get thicker.


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