EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Exploring lava dome mechanics & structure: how does stability change as a function of rock strength?

Claire Harnett1 and Michael Heap2,3
Claire Harnett and Michael Heap
  • 1University College Dublin, School of Earth Sciences, Dublin, Ireland (
  • 2Université de Strasbourg, CNRS, Institut Terre et Environnement de Strasbourg, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France
  • 3Institut Universitaire de France (IUF), 1 rue Descartes, Paris 75231, France

Lava dome collapse hazards are intimately linked with their morphology and internal structure. We present new lava dome emplacement models that use calibrated rock strengths and allow material behaviour to be simulated for three distinct units: (1) a ductile, fluid core; (2) a solid upper carapace; and (3) disaggregated talus slopes. We first show that relative proportions of solid and disaggregated rock depend on rock strength, and that disaggregated talus piles can act as an unstable substrate and cause collapse, even in domes with a high rock strength. We then simulate sequential dome emplacement, demonstrating that renewed growth can destabilise otherwise stable pre-existing domes. This destabilisation is exacerbated if the pre-existing dome has been weakened following emplacement, e.g., through processes of hydrothermal alteration. Finally, we simulate dome growth within a crater and show how weakening of crater walls can engender sector collapse. A better understanding of dome growth and collapse is an important component of hazard mitigation at dome-forming volcanoes worldwide.

How to cite: Harnett, C. and Heap, M.: Exploring lava dome mechanics & structure: how does stability change as a function of rock strength?, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-691,, 2022.