[Montanaro] Permeability’s role around magma bodies: a way for gradually deforming or suddenly erupting

German Title: Permeability’s role around magma bodies: a way for gradually deforming or suddenly erupting

Abbreviation: 382

Current Status: approved


Main Applicant:Dr. Cristian Montanaro


Resources Recipient


Other Persons

Dr. Kai-Uwe Hess
Dr. Bettina Scheu
Prof. Dr. Donald Bruce Dingwell


Conveyor Begin: 1 February, 2018
Conveyor End: 31 January, 2020
Conveyor Duration: 24
Year: 2018


Description

Many of Iceland’s electricity-producing geothermal fields are located within or near explosion craters produced by steam-driven eruptions. The Krafla geothermal area is a prime example of such a valuable infrastructure resource with an uncertain hazard future. The Vití steam-driven (phreatic) eruption occurred at Krafla prior to the effusive fissures of Mývatn Fires (1724-29): trigger of the eruption and cause for its location far outside the main eruptive fissures, are unknown. In this light, the recent findings from the IDDP 1 - a rhyolite melt at about 2 km depth under Krafla Caldera, and a conductive boundary layer (CBL) separating the magmatic source from the overlying hydrothermal system - raised a key question: If the intrusion formed during the last Krafla Fires eruption (1975 84), why did it not produced any explosive eruption (as Vití)? Past work suggests that rock’s permeability in particular, determines whether overpressurized fluid may either fragment the surrounding rocks or escape from it via effective outflowing. A level such as the CBL, which permeability is undefined, may represents a prime lithological barrier above the rhyolite magma. The research proposed here aims to the understanding of magma/hydrothermal systems and its implications for the potential volcanic hazards, same as in the scientific program suggested for the KMDP-drilling project. Two main synergetically interlinked objectives can be named for this proposal: i) constrain the resilience and response of the CBL to P-T perturbations such as rapid/step decompression (e.g. natural or induced by exploitation), or slow-to-rapid heating (magma intrusion), and ii) constrain the timescale for which the CBL’s changes from having a deforming (resilient) behaviour to a brittle response (failure). Data and samples from drillings provide a unique opportunity to foster our understanding on the role of permeability around magma bodies. We propose to address this knowledge gap by combining a new rock datasets from the KMDP drilling with physical laboratory decompression-explosion experiments. Using the world’s largest volcanic shock-tube, we will simulate possible scenarios as the CBL responses to controlled rapid decompression, as well as to rapid and slow heating processes.