Özet
Understanding further the nature and evolution at lithospheric scale of the Sea of Marmara on the North Anatolian Fault needs constraints on the deep crustal and Moho spatial variation. This has been probed here with offshore-onshore and OBS, Ocean Bottom Seismometer refraction seismics, in addition to coincident MCS, marine multichannel reflection seismic profiles over the whole North Marmara Trough. The diverse strikes of MCS profiles in a dense grid allow to avoid misinterpretation of late echoes in the deep basin as Moho reflections and attribute them to sidesweeps. Moho is instead positively identified from reversed observations of first-arrival head and refracted waves at the top of the mantle obtained at large offset by land stations. A significant and sharp reduction in its depth, on the order of 5 km occurs beneath both the eastern and western rims of the North Marmara Trough, with a more progressive crustal thinning from the south. The wide-angle reflections on OBS and land stations document in addition to Moho the top of a lower crustal reflective layer, which is also sampled by MCS profiles, and appears to follow Moho topography. The dense grid of MCS profiles along the southwestern margin of the North Marmara Trough reveals a dipping reflector through the upper crust with tilted basement blocks on top. This low-angle fault is suggested as a normal sense detachment extending in depth towards the reflective lower crust. The upwarp of the Moho and lower crustal layer towards the North Marmara Trough suggests that crustal thinning occurs mostly in the upper crustal part, with lateral transport of the material towards WSW in the footwall of the detachment, and possibly other features to the south, in the motion of Anatolia with respect to stable Eurasia oblique to the North Marmara Trough. Thinning can be accommodated in an asymmetric partitioning of the displacement on several branching faults at lithospheric scale.
| Orijinal dil | İngilizce |
|---|---|
| Sayfa (başlangıç-bitiş) | 1-21 |
| Sayfa sayısı | 21 |
| Dergi | Tectonophysics |
| Hacim | 467 |
| Basın numarası | 1-4 |
| DOI'lar | |
| Yayın durumu | Yayınlandı - 20 Mar 2009 |
Finansman
The SEISMARMARA seismic experiment was operated as a joint integrated project between Turkish and French scientists, research institutions and universities, technical facilities, and funding agencies, coordinated by TUBITAK in Turkey (Naci Görür) and INSU-CNRS in France (Rolando Armijo). N/O Nadir and the seismic source and streamer operated by IFREMER/GENAVIR were allocated in the frame of a special extension of deadline for the regular call for proposals for use of these French national facilities. The OBS provided and operated by ISV Hokkaido, Japan, as well as the land refraction stations of the INSU pool were funded by ACI CATNAT of the French Ministry of Education and Research, with additional support and personnel of these institutions and of Turkish ones coordinated by TUBITAK. R/V Sismik 1 of MTA was operated for TUBITAK, who also funded Turkish participation to all other aspects, in the frame of the cooperative Turkish–French program following the destructive earthquakes, coordinated by Naci Görür and Rolando Armijo. MCS Processing has been done with the Geovecteur software of CGG at the CNRS-IPGParis, PROMAX at the University of Pau. We thank the masters and crews of N/O Nadir, R/V Sismik, the scientific and technical teams of the MCS, OBS and land stations deployments, as well as data recovery and processing. The Shipboard Party comprised in addition S. Bazin, S. Cetin, S. Singh, A. Vigner, and R. Saatcilar. We acknowledge the critical comments of Pr. E. Flueh and anonymous journal reviewers IPGP contribution 2462.
| Finansörler | Finansör numarası |
|---|---|
| Australian Carbon Innovation | |
| Società Italiana di Virologia | |
| Türkiye Bilimsel ve Teknolojik Araştirma Kurumu | |
| Ministère de l'Education Nationale, de l'Enseignement Superieur et de la Recherche |