Summary
The subduction of oceanic ridges and seamount chains is thought to strongly influence the segmentation of megathrust faults, as well as the geometry and dynamics of subducting slabs. However, the physical processes involved remain poorly understood. Along the Andean margin, major transitions between flat and steep slab geometry coincide with the subduction of large oceanic features, making this region a natural laboratory to explore these interactions. In this seminar, I will present results from the ERC DEEPtrigger project, based on dense seismological and geodetic observations from southern Peru and the Atacama region of Chile. By combining seismic tomography, earthquake catalogs, satellite geodesy (GNSS) and SAR interferometry, we image plate structure and geometry, deformation of the upper plate, the distribution of slow and fast earthquakes, and potential fluid pathways. These complementary datasets allow us to address several key questions: Can ridge subduction sustain flat slabs? How is deformation transferred from the megathrust to the upper plate? Does slab steepening involve slab tearing? And how do subducted bathymetric features influence megathrust coupling and the balance between slow slip and seismic rupture? I will illustrate these processes using selected examples from the Peru–Chile subduction zone, focusing on the regions where the Nazca and Copiapó ridges enter the subduction zone.
Brief biography
I am a French geodesist whose research combines space geodesy (GNSS and InSAR) with seismology to better understand fault behavior and earthquake processes throughout the seismic cycle notably on subduction zone. I develop methods based on signal processing or machine learning to detect subtle geophysical signals such as slow slip events or low frequency earthquakes. I integrate geodetic and seismological observations together with kinematic and mechanical models to improve our understanding of the seismic cycle. I received my PhD in Earth Sciences from École Normale Supérieure in Paris (2003) and completed postdoctoral fellowships at Delft University of Technology and UCLA, working on GPS geodesy, plate tectonics, and active faulting. Since 2015, I have been full Professor at Université Grenoble Alpes (ISTerre/OSUG), after earlier appointments at IPGP and Grenoble. I am deeply involved in international research infrastructures and community service. I coordinate GNSS products within the European Plate Observing System (EPOS) and lead the EPOS GNSS processing center hosted by CNRS-OSUG. I serve on committees for SZ4D and EPOS, act as Associate Editor for AGU journals, and I am President-elect of the AGU Geodesy Section. My ERC-funded DEEPtrigger project investigates subduction earthquake preparation processes, notably through large-scale seismo-geodetic deployments in Chile and Peru. Beyond research, I am committed to teaching, mentoring, open data, and fostering inclusive scientific environments.