Modelling of sill inception, propagation and growth

We are pleased to inform about a publication from our research group. The paper is published in Earth And Planetary Science Letters and available online at

 http://www.sciencedirect.com/science/article/pii/S0012821X15001879

A model of magma propagation in the crust is presented using a series of analogue experiments, where dyed water is injected at a constant flux into layers of solidified gelatine. Digital image correlation (DIC) is used to calculate incremental strain and finite strain in the deforming host material as it is intruded. This is mapped in 2D for the developing experimental volcanic plumbing system that comprises a feeder dyke and sill. Since the gelatine deforms elastically, strain measurements correlate with stress. Our results indicate that, for constant magma flux, the moment of sill inception is characterised by a significant magmatic pressure decrease of up to ∼60%. This is evidenced by the rapid contraction of the feeder dyke at the moment the sill forms. Sill propagation is then controlled by the fracture properties of the weak interface, with fluid from the feeder dyke extracted to help grow the sill. Pressure drops during sill inception and growth are likely to be important in volcanic systems, where destabilisation of the magmatic plumbing system could trigger an eruption.

 

Model of dyke and sill formation

Model of dyke and sill formation

 

Screenshot_2015-04-29-08-27-33

About the author

2 thoughts

  1. David Boutelier

    This paper received some attention in the media:

    http://www.theguardian.com/world/2015/may/19/geologists-use-jelly-lasers-and-water-to-unravel-mystery-of-volcanic-eruption

    http://www.independent.co.uk/news/science/are-scientists-finally-close-to-realising-what-triggers-volcanic-eruptions-10254983.html

    http://phys.org/news/2015-05-trigger-volcanic-eruptions-jelly-lasers.html#

    http://www.huffingtonpost.com/2015/05/17/trigger-volcanic-eruptions_n_7292090.html

    http://www.iflscience.com/physics/pressure-drop-unleashes-eruptions

    and my collaborators and myself have discussed the topic a few times on radio.

  2. Arthur Vachon

    Great work! That is the kind of info that are meant to be shared around the net. Disgrace on search engines for not positioning this submit higher! Come on over and seek advice from my site . Thanks =)

    N/A

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