Strike-slip faults are often segmented by step-overs resulting in a variety of deformation styles such as constraining bends, releasing bends and rotational deformation. These step-overs or discontinuities within the fault zones create segment boundaries that are associated with complex geometric patterns. Our knowledge from recent studies of dynamic earthquake models suggests that the complexity of geometry and the distance between segment step-overs may arrest earthquake rupture propagation. To understand this phenomenon, here we focus on the North Anatolian Fault (NAF) as a worldwide example, which has ruptured in the last century with a sequence of east-west propagating 8 large earthquakes over its 800 km morphological trace. This well-known sequence is now pending on its eastern and western ends creating seismic gaps that are associated with transtensional step-overs. The westernmost step-over of the NAF forms the crustal scale Sea of Marmara basin and the smaller fault steps within bound three deep basins which combines strike-slip and normal faulting. Our constraints based on the 3D study of geometry and morphology of the submarine faults using a dense coverage of complementary high-resolution sensors (bathymetry, shallow and deep penetration profiling) put more insight into the characteristics of fault segmentation and rupture propagation along the NAF in the Sea of Marmara. Accordingly, clear morphologic evidence of recent faulting show that the transtensional jogs has also played a crucial role to stop earthquake rupture propagation in the Sea of Marmara.
Dr. Gulsen Ucarkus has started her career in geology with a BS in Engineering Geology from Istanbul Technical University. She has focused in paleoseismology during her MSc in Eurasia Institute of Earth Sciences in Istanbul. During that period, she also worked in several consulting projects of seismic hazard assessment including the Baku–Tbilisi–Ceyhan pipeline project. She then got a scholarship from French Embassy in Ankara and started a joint PhD program with Institut de Physique du Globe de Paris in France. She participated to several international scientific cruises in the Sea of Marmara, Turkey, which targeted to investigate active fault segments of North Anatolian Fault. During her PhD, she has been trained to employ complementary geophysical data from these cruises to conduct a detailed study on the characteristics of active faulting along the NAF in the Sea of Marmara. Dr. Ucarkus is now doing a post-doctoral study at Scripps Institution of Oceanography.
