Finding how earthquakes and storms impact the building of landscapes
Unravelling how tectonics, climate and surface processes act and interact to shape the Earth’s surface is one of the most challenging unresolved issue in Earth Sciences. The foundations of modern quantitative geomorphology have been built within the paradigm of steady-state landscapes responding to slow changes in climatic or tectonic conditions, mainly rainfall or uplift rate. Yet, recent results demonstrate that landscapes are rhythmed by (potentially extreme) storms and earthquakes. These perturbations catalyse geomorphological processes by triggering numerous landslides and lead to a prolonged and transient evolution of the landscape that dominate records of modern erosion. The FEASIBLe project therefore calls for a complete re-assessment of the role of short-term climatic and tectonic perturbations in shaping mountain landscapes and for a paradigm shift from steady-state to constantly perturbed landscapes. My ambition is to push forward our understanding of the short- to long-term dynamics of perturbed landscapes and in turn to unlock our ability to read landscapes in terms of earthquake and storm activity. To succeed in this endeavour, the FEASIBLe project will rely on the development of a new generation of landscape evolution model and of novel approaches to intimately monitor landscape heterogeneities and evolution in Taiwan, New-Zealand and Himalayas at high-resolution. The first work packages (WP1-2) will combine field-data analysis and numerical modelling to investigate landslide triggering and the post-perturbation sediment evacuation and landscape dynamics. I will then blend these elementary processes with a statistical description of climatic and tectonic perturbations in a new generation of landscape evolution model (WP3). This new model will be then applied to diagnose the geomorphological signature of fault “seismogenic” rheology (WP4) and to explore the role of post-glacial hot-moments of landscape dynamics on Quaternary landscape evolution (WP5).