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We would like to develop more the observation offault geometry and its effect on subduction zoneand strike slip fault systems. For example, bysystematically calculating the stresses induced bythe fault geometry and the long term slip of thefault.Mature faults are known to be less rough that2019.○○.○○○○○○○○○○○○○2023.2.21令和4年度成果発表会Example of a 3D fully dynamic earthquake cycle simulation. The model parameters are following SCEC benchmark BP7. This figure represents the slip velocity of an earthquake, at different time, breaking a velocity-weakening asperity.In order to answer these questions, we try to develop new analytical tools and numerical models.(1)Numerical models: We developed new numericalmodels of earthquake cycles in the context of non-planar fault geometry. One current limitation ofsuch kind of modelsis the running timeconsumption. This is why, we developed a fully-dynamic spectral Boundary Element Method, in3D, that can handle non-planar fault geometries.Taking advantage of the Fourier transform, itaccelerates the calculation and can be computedon regular desktop.(2)We apply the tools that we have developed tobetter understand the role of fault-geometry onthe earthquake mechanics, its evolution and howit affects the seismic cycle behavior.We hope that in the long term, these developments will improve hazard map for earthquakes by integrating the fault geometry.younger fault. We would like to develop a model ofearthquake cycle to understand this phenomena,i.e.: the evolution of fault geometry with on-goingslip.Pierre ROMANETPoint■Development of a new numerical methods to model earthquake cycle simulations onnon-planar faults (spectral boundary element method)■Development of new analytical tools using semi-analytical solutions■Observation of the effect of plate geometry or fault-geometry on the dynamics ofearthquakesOutlineDespite the fact that fault geometry is one of the parameter that can be measured either directly (by mapping fault trace) or indirectly (by analyzing micro-seismicity), its role in the process of earthquake dynamics is still not well understood. Which fault geometrical feature will promote large earthquake generation? Which fault geometrical features will impede large earthquake? How is the fault geometry evolving with on-going slip on the fault and how does it affect the behavior of earthquakes? Future researchThe last year, we successfully generalized our work to 3D medium. We are now able to compute 3D fully-dynamic earthquake cycle simulation on slightly non-planar fault, only using a regular desktop.Understanding the evolution of fault geometry with on-going slip Earthquake and Tsunami Research Division