Why do large earthquakes not always occur at regular time interval on a given fault? Present-day physical models on repeating ruptures are poorly constrained and can yield inconsistent predictions. To be able to anticipate future seismic catastrophe, we ne ed to measure and understand the irregularities in the seismic cycle.The observed aperiodic seismic behavior may have different causes, including intrinsic properties of faults, seismic or postseismic interactions between faults, or variations in strain ac cumulation. To get deeper insights in the mechanisms at work, we propose to establish the seismic history over several thousand of years of a main strike-slip fault system in Turkey. The targeted North Anatolian plate-boundary is particularly suitable beca use of the type of faulting, its rapid deformation rate (up to 24 mm/yr), its relative structural simplicity and its particularly simple seismic behavior characterized by cascadingsequences of M>7 earthquakes.Another remarkable feature is the seeming co rrelation between the seismicity of the North Anatolian Fault and of adjacent strike-slip plate-boundaries (the East Anatolian Fault and the Dead Sea Fault). This transfer in seismic activity needs to be confirmed and would have broad implications regardin g continental-scale seismic coupling. The present project seeks to obtain a most extensive chronology of past events along both the North and the East Anatolian Faults. For that purpose, we plan to use a diverse array of complementary techniques, involving trenching across the fault combined with subsurface geophysics, dating of displaced geomorphic features and drilling of lake sediments along the fault trace.
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