Multiple Effects of Ice Load Changes and Associated Stress Change on Magmatic Systems

• Main Authors: F. Sigmundsson, F. Albino, P. Schmidt, B. Lund, V. Pinel, A. Hooper, PAGLI, CAROLINA
• Other Authors: Bill McGuire, Mark Maslin, F., Sigmundsson, F., Albino, P., Schmidt, B., Lund, V., Pinel, A., Hooper, Pagli, Carolina
• Format: Book Part
• Language: unknown
• Published: John Wiley & Sons, Ltd 2013
• Subjects: ice load; magma stre; glacial unloading; crust/mantle; magma geometry; Katla; Ice cap; Iceland
• Online Access: http://hdl.handle.net/11568/500675; https://doi.org/10.1002/9781118482698.ch5; https://onlinelibrary.wiley.com/doi/10.1002/9781118482698.ch5

Ice retreat on volcanoes reduces pressure at the surface of the Earth and induces stress changes in magmatic systems. The consequences can include increased generation of magma at depth, increased magma capture in the crust and modifcation of failure conditions of magma chambers. We review the methodology to evaluate each of these effects, and consider the infuence of ongoing ice retreat on volcanoes at the mid-Atlantic divergent plate boundary in Iceland. Evaluation of each of these effects requires a series of assumptions regarding the rheology of the crust and mantle, and the nature of magmatic systems, contributing to relatively large uncertainty in response of a magmatic system to climate warming and associated ice retreat. Pressure release melting caused by ice cap retreat in Iceland may at present times generate a similar amount of magma to plate tectonic processes, larger than previously realized. However, new modelling shows that part of this magma may be captured in the crust, rather than being erupted. Gradual retreat of ice caps steadily modify failure conditions at magma chambers, which is highly dependent on their geometry and depth, as well as the details of ice load variations. A model is presented where long-term ice retreat at the Katla volcano decreases the likelihood of eruption, because more magma is needed in the magma chamber to cause failure than in the absence of the ice retreat.