seismic off-fault Deformation: A multi-scale iMAGing to constrain Earthquake energy budget

ended

Earthquakes are one of the deadliest geo-hazards in the world causing huge societal and economic impact. Destructive earthquakes are generally represented by ruptures which nucleate, grow and terminate along pre-existing faults with catastrophic strain energy release. Seismological observations and theoretical arguments demonstrated that most of earthquake energy is dissipated into heat by friction within the core of faults at depth. The remaining energy amount is the one driven to the Earth surface by seismic waves and associated to the generation of extensive DAMAGE in the vicinity of seismic faults. Vast research was recently performed to investigate on-fault mechanisms during earthquakes whereas much less has been done to constrain the physical processes and energy sinks associated to coseismic off-fault deformation. I propose here to systematically study off-fault coseismic damage in carbonates, which are the rocks where most of the destructive seismicity striking Europe is hosted. The proposed research is innovative since it tackles a scientific topic which was so far overlooked with a multiscale interdisciplinary approach combining: detailed field structural and geophysical characterization of exhumed active fault zones, compressive and tensile dynamic loading tests on carbonate rocks, and microstructural-petrophysical characterization of natural and experimental fault rocks. This integrated strategy will lead to build a wealth of novel datasets to quantify the damage structure and scaling relations of seismogenic fault zones in carbonates. Newly conceived rock deformation experiments will then help to determine the mechanical origin of coseismic damage in carbonates. The research will be conducted at Universitè Grenoble-Alpes with a secondment at University of Manchester. The experience of the supervisors and the equipment at both organizations will guarantee the successful progress of the research and my professional growth as independent researcher.