Offshore/onshore correlation of the North‑Anatolian fault deformations in the Western Sea of Marmara

Abstract

Newly collected high-resolution seismic reflection and magnetic data collected offshore ofthe Ganos Fault (NW Turkey) in the western Sea of Marmara, along the submerged portionof the North-Anatolian Fault, highlight the presence of a complex fault pattern. Based onthese data, we propose a new tectonic model for this key region, connecting the onshorefault pattern to the transtensional basins of the deepest Sea of Marmara. According to thisnew model, three main faults control the deformation pattern of this region, fault SF1, atectonic element that shapes the Tekirdağ Basin, and fault SF2, which although not affectingthe sea floor, is structurally related to SF1. Another fault we called SF3, connects theoffshore to the Ganos fault onshore creating a transtensional pattern nearby the shelf. Allsuch kinematic indicators witness an incipient activity, and a seismogenic potential thatshould be determined by a detailed mapping of both the surficial expression of fault at theseafloor, and the deformation pattern observed in the post-glacial sedimentary sequence.The active fault pattern detected nearby the coastal areas and their structural relationshipswith the Tekirdağ basin show that it could be interpreted as a negative flower structure,which accommodates strain partitioning. This observation is crucial to seismic hazardassessments in this region that has been the site of destructive earthquakes in the recentand remote past