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My research has focused on two main directions: (1) Studying large-scale active fault-related structures deforming the lithosphere by working at the interface between geomorphology, earthquake geology and structural geology; (2) Modeling fault interaction over the short term and the kinematics of deformation processes over the long-term. Combining both approaches allows to work out the deformation mechanisms of the lithosphere. STUDY OF STRIKE-SLIP PLATE-BOUNDARIES: The North and East Anatolian Fault System in Turkey is particularly suitable to understand the geodynamics of plate boundary deformation and continental extrusion processes. It forms a basis for comparison with other structurally more complex continental transform faults. Short-term Deformation Processes. Quantitative geomorpholology is an unparalleled tool to characterize active deformation along a given fault system. More specifically, accurate measurements and dating of surface offsets, small and large, provide average slip rates over periods thousands of years long, that spans a large number of seismic cycles. Specifically studying offset geomorphological markers all along the North Anatolia Fault has allowed to constrain its Holocene slip rate (20 mm/yr) and the degree to which shear deformation is localized on the present active fault trace and released seismically (Hubert-Ferrari et al., JGR, 2000). Long-term spacial and temporal deformation processes. Characterizing the long-term evolution of the plate boundary system in Turkey is possible due to the simplicity of the fault system. Large-scale geological and geomorphological offsets can be unambiguously defined, and one can use the interplay between deformation and volcanism or sea-level change in the Mediterranean Sea. The later work has shown that the North Anatolian Fault acts as a transform plate boundary with a uniform 80���90 km total displacement (Hubert-Ferrari et al., JGR, 2002; Armijo et al., Geology, 1999). Furthermore the deformation of a volcano that sits across the North Anatolian Fault eastern terminaison suggests that the system has evolved in two main phases characterized by different fault slip rates (Hubert-Ferrari et al., submitted to Terra Nova, 2004). STUDY OF THE TIANSHAN INTRACONTINENTAL MOUNTAIN BELT: The Tianshan is a significant opportunity for the study of fold-and-thrust-belt deformation and moun- tain building because of the combinaison of exceptional surface exposures of actively deforming structures and high-quality seismic reflection profiles imaging the subsur- face. This enabled us to form well-constrained relationships between deformation of the land surface and the fundamental underlying processes of deformation, which is normally difficult or impossible to do. Focusing particularly on Kuche and Aksu areas of the central southern Tianshan we provide: (1) new ma jor data on the deep structure and rates of deformation of the southern Tianshan (Hubert-Ferrari et al., in preparation, 2005); (2) new cosmogenic data on the ages of the last glacial maximum and post-glacial incision in the southern Tianshan, leading to a documentation of an irregular earthquake cycle over the last 15 ka on the main frontal thrust fault (Hubert-Ferrari, JGR, 2005); (3) new widely applicable quantitative technique and theory for analyzing large-scale upper crustal folding (Hubert-Ferrari et al., AAPG, 2004); (4) a number of relationships between well constrained deep blind structures and their active surface expressions. In particular we have discovered numerous examples of neotectonic fold scarps which record the incremental growth of major structures (Hubert-Ferrari et al, submitted to J. Geophys. Res, 2005). MODELING: A thorough understanding of the mechanics of lithospheric deformation can only be achieved by combining field observations and numerical modeling. Fault interaction. Part of the team leader modeling work has focused on fault inter- action, which is a fundamental feature of seismicity, leading to earthquake sequences, clustering and aftershocks. Her first work on the sub ject was an investigation of the Coulomb stress interaction of a single earthquake sequence (Hubert et al., EPSL, 1996). Subsequently, the technique has been significantly improving, extending the time periods examined by several orders of magnitude (Nalbant, Hubert-Ferrari and King, JGR, 1998; Hubert-Ferrari et al., Nature, 2000). We specifically demonstrated that stress interaction plays a crucial role in the long-term evolution of seismic pattern. The success of these works heavily relied on our in-depth knowledge of the tectonics of the areas under study. Kinematics of large fault systems. The basic modeling hypothesis is that the lithosphere is strong over the long term, with deformation (1) localized into narrow zones and (2) penetrating through the entire thickness of the lithosphere. This assumption is a plausible and well-argued alternative to the conventional models of viscous flow and distributed deformation at depth beneath an elastic crust. In our models we thus used simple linear elasto-plastic models to understand the long-term evolution of geological structures, fault motion and the dynamical interaction between fault blocks on a larger scale. In Hubert-Ferrari et al. (GJI, 2000), we have shown that propagation processes in continental lithosphere are plausible, and propose simple models that can explain major features of the evolution of the Gulf of Aden and of the East and North Anatolian Faults in Turkey.
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