Chapter 7 Structural Development of Calderas: A Synthesis from Analogue Experiments

摘要: Abstract A number of analogue models studying caldera architecture and development have been recently performed under different conditions (apparatus, materials, scaling parameters, stress conditions). An overview the experiments reveals a consistent scenario for structure development, regardless imposed boundary condition. In fact, complete collapse can be summarised through four main stages, proportional to amount subsidence, progressively characterised by a: (1) downsag; (2) reverse ring fault; (3) peripheral downsag (4) normal fault. brief comparison natural cases shows that all these experimental structures, as well their are commonly observed, even at various scales. Such consistency between nature suggests general applicability results. The evolutionary stages adequately explain established end-members (downsag, piston, funnel, piecemeal, trapdoor) along continuum, where one or more may correspond specific stage. While such continuum is controlled progressive geometries result from secondary contributory factors (roof aspect ratio, symmetry, pre-existing faults). proposed scheme incorporates not only geometric features calderas, but importantly, also genetic features.