A New Dike Propagation Model Linking Seismicity and Rock Damage Mechanics

Dikes feed volcanic eruptions, causing devastating hazards and global impacts. Monitoring magma ascent through dike propagation can significantly enhance hazard assessment and mitigation. However, direct observation of dike propagation remains elusive. Among the available data, dike-induced earthquakes offer the best tracing of subsurface dike movement. These earthquakes may facilitate dike propagation by damaging the rock or slowing down the dike by releasing accumulated stresses. Yet, the relationship between these earthquakes and rock damage remains unclear. To clarify this relationship, we have developed a new dike propagation model that couples damage mechanics with porous flow to explore the local stress field's influence on fluid mobility within the dike. Our model's results show that the energy released during the rock-damaging process aligns with the seismicity induced by the dike. Furthermore, the model-calculated local stresses near the dike can explain the observed fault plane solutions associated with dike propagation. The new model also reveals the controls on magma ascent velocity, intrusion geometry, and surface deformation, with implications for other volcanic systems such as Bardarbunga, La Palma, and Piton de la Fournaise volcanoes.