9 comments on “The 2018 Eruption Sequence at Mayon, Philippines

  1. Mayon had Strombolians eruption with lava fountains shooting several hundreds of meters into the air. What caused this volcano to shift from pyroclastic flows into lava fountaining and has it do do with alternating layers of basalt and more evolved magma inside its main magma chamber?

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    • Still trying to figure out how such a steep and active volcano hasn’t suffered a flank collapse / debris avalanche yet. Wondering if the layered lava flows combined with soft material removal by rain / typhoons tends to make the cone more substantial than the majority of other stratovolcanoes.

      I think there is some mixing in the magma chamber. Unable to tell how much at this time. The only caldera I found along this portion of the Bicol Arc was Irosin now occupied by Bulusan. Eruptions appear to be sufficiently regular so that there is not an overabundance of dacites either produced or erupted. Cheers –

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    • I like what you did there.
      Mayon had Strombolians eruption with lava fountains shooting several hundreds of meters into the air. What caused this volcano to shift from pyroclastic flows into lava fountaining and has it (do do) with alternating layers of basalt and more evolved magma inside its main magma chamber?

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    • Hi Dawmast and Ligma,

      Lava fountains, lava flows and occasionally larger explosions with pyroclastic flows – all belong to the characteristics of Strombolian activity. Even without substantial changes in the magma composition, the main actor here is the gas content.

      With Strombolian type, you have more sticky magma (compared to very liquid Hawaiian type eruptions). Gas bubbles rise slowly from very deep down, and often many small bubbles combine to a large one on their way up. Such large bubbles cause explosions and lava fountains when they reach the crater. These bubble-blasts can be quite powerful as the gas pressure is high. This would be the “normal” Strombolian behaviour we can see. At the end of one batch the magma gets much depleted of its gases and therefore looses pressure. This is when the remaining lava just flows out without fountaining.

      After one eruption has ended and the conduit solidified, it will be much harder for the next batch of fresh magma to break through. Moreover, Mayon’s lavas are thick enough to build lava domes between eruptions. These usually get destroyed by the next onset of gas-rich magma. This is when stronger explosions happen again. Also, during quieter times, surface water may accumulate in the crater, and may cause phreatic eruptions with a lot of ash.

      All these conditions can cause large blasts within a Strombolian type eruption and therefore may also cause pyroclastic flows. It does not need to have to do with a change in magma composition.

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  2. Hey, are you all helping vote for and “promote” the best volcanoes in the Twitter Volcano Cup? I can’t right now but will join in mightily in a few days!

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  3. Thank you for a fascinating article! The Philippines are in my mind as our daughter is vacationing there right now. Understandably, she’s staying well away but she knows my interest in Mayon! I am hoping she might be near enough for some photos (she is a photographer) but it’s unlikely.

    Interesting to see Kadovar is still on the go, to.

    Thanks!

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  4. Howdy all –

    Interesting paper from Science Alert on the Chicxulub impactor unzipping the mid-ocean ridges and spreading centers. I have long thought that a large impact event could trigger volcanic activity from pressurized systems that were not currently in eruption by flexing brittle rock capping the intruding dike / sill. The impact simulator gives a felt earthquake M 10.2 on the other side of the planet from the impact site, so there would be enough energy delivered to shake things up a lot. Worth a read. Cheers –

    https://www.sciencealert.com/asteroid-impact-underwater-eruptions-caused-dinosaur-extinction

    https://impact.ese.ic.ac.uk/ImpactEarth/ImpactEffects/

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