Numerical modelling of caldera dynamical behaviour

摘要: SUMMARY The study of the mechanics caldera formation can yield valuable insight into behaviour near-surface magma chambers and their mechanical interaction with crust. We have addressed problem physical processes responsible long-term ground deformation from emplacement in crust to a final resurgent stage. A model based on thermally coupled elastovisco-plastic rheology finite formulation has been used, solved via element approximation. The history an ideal is modelled following two stages. 1 A doming phase corresponding growth chamber. This stage constrained by values amplitude, half-width time constant regional range realistic over-pressures. uplift linked plastic strain field within crust, which strongly depends upon pressure temperature fields. 1 A resurgence results collapse stage, instantaneous change shape topography. chamber passive this basically similar crater relaxation process. rebound amplitude are controlled length-scale collapse. gravitational very likely mechanism explaining large without over-pressure mechanisms. For most intracrustal loading processes, crustal critically influenced relative importance upper (pressure-dependent plasticity) versus lower (temperature-dependent viscosity). Because part deform time-dependent dissipation, it may be for variations that occur moderate variations. By contrast creep middle acts as regulating medium.