Evidence and implications of massive erosion along the Strait of İstanbul (Bosphorus)

Gökaşan, Erkan; Tur, Hüseyin; Ecevitoğlu, Berkan; Görüm, Tolga; Türker, Ahmet; Tok, Buğser; Caglak, Faruk; Birkan, Halim; Şimşek, Mehmet

doi:10.1007/s00367-005-0216-3

Cited by 39 publications

(22 citation statements)

References 19 publications

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“…Such high velocities could indeed be responsible for massive erosion of the channel bed, especially considering that the latter is formed by soft silts. A similar process has been documented as important in the strait of Istanbul by Gökaşan et al (2005), who described the existence of an inner channel within the strait which could be formed by an abrupt flooding of the Black Sea by Mediterranean waters at the beginning of the latest connection between the Marmara and the Black seas. Holcombe et al (1997) also described overdeepened channels in the bathymetry of western Lake Erie due to intense wind-driven water circulation through the restricted passages.…”

Section: Discussionsupporting

confidence: 59%

Geodynamical processes in the channel connecting the two lobes of the Large Aral Sea

Roget

Zavialov

Khan

et al. 2009

Hydrol. Earth Syst. Sci.

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Abstract.Reasons for the existence of the channel connecting the two lobes of the present Large Aral Sea are discussed. In situ measurements in 2005 show that differences between the measured depths and those contained in the available digital bathymetry of the lake are considerably different at the channel (7.5±0.9 m, at nine measurement stations along it) and at the northern part of the eastern lobe (1.6±0.3 m, at six stations from the western to the eastern shore). Differences in the misfits observed in the two zones are discussed and thought to be a consequence of the variation of the transversal area of the channel as it enters the eastern lobe, which would affect the flow velocity and thus the strength of the erosion process at the bottom. Field data together with satellite images have been used to modify an original digital bathymetry of the lake and have been implemented into a 3-D hydrodynamical model. A numerical simulation shows that a wind of 12 m/s blowing from the east (112 • ) generates velocities of up to 45 cm/s in the channel, allowing denser water from the eastern lobe (salinity: 132 g/kg) to flow about 38 km towards the fresher western lobe (salinity: 98 g/kg) in one day. The effect of the inflow on the vertical structure of the western lobe is also illustrated. Although nowadays the channel will be soon a thing of the past, in a more general context, the Aral Sea is presented as an example showing that geomorphologic and geophysical processes, along with hydrological and atmospheric processes, must be taken into account for short-term predictions.

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Section: Discussionsupporting

confidence: 59%

Geodynamical processes in the channel connecting the two lobes of the Large Aral Sea

Roget

Zavialov

Khan

et al. 2009

Hydrol. Earth Syst. Sci.

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“…The domain is extended into the neighboring seas in the form of artificial rectangular boxes with open boundary conditions specified at the ends. High resolution bathymetry data obtained from Gökaşan (2005), those sampled on board the NATO research vessel NRV "Alliance" (1995)(1996) and digitized from maps of the Turkish Navy Office of Navigation, Hydrography and Oceanography (ONHO) have been combined with data from the General Bathymetric Chart of the Oceans GEBCO 08 (http:// www.gebco.net) and coastline data from METU-IMS (Middle East Technical University, Institute of Marine Sciences) to construct the model bathymetry, which later has been minimally smoothed, setting minimum depth of 25m for shallower regions gently joined with the steep interior topography. This setup forms the basis of the "ONLYBOS" case.…”

Section: Model Setupmentioning

confidence: 99%

Water Exchange through Canal İstanbul and Bosphorus Strait

Sözer

Özsoy

2017

Medit. Mar. Sci.

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The Turkish Straits System (TSS) regulates the transports of water, material and energy between the Black Sea and the Mediterranean Sea. Amidst existing environmental threats to the region surrounding İstanbul, the environmental footprint of the proposed Canal İstanbul project needs to be evaluated through methods of natural science. We take the elementary step to answer the particular problem of coupled strait dynamics by adding the Canal to an existing hydrodynamic model and estimate changes in their common response. Compared to the virtually unmodified exchange flow in the Bosphorus, the flow in the Canal has a weak lower layer current component, contrasted with intense currents at the exit controls at its junction with the Marmara Sea. The net flux through this simplest hypothetical TSS configuration is considerably increased for a given sea level difference across the system. The modified regime is expected to have climatological consequences.

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“…This erosional surface was rejuvenated by tectonic activities and sea level fluctuations during the Quaternary period when some parts of the mature erosional surface were lowered by faults to became the base level for deposition, while other parts were elevated (Emre et al, 1998;Demirbag et al, 1999;Yaltırak et al, 2002). One of the depressional areas developed in this period is the Strait ofİstanbul (Alavi et al, 1989;Gökaşan et al, 1997Gökaşan et al, , 2005aDemirbag et al, 1999;Oktay et al, 2002;Fig. 6(a)).…”

Section: Morphology Of the Study Areamentioning

confidence: 99%

“…The morphology of the terrestrial area around the Marmara Sea, including theİstanbul and Kocaeli Peninsulas, is dominantly implied by a mature horizontal erosional surface that developed during the Upper Miocene-Pliocene pe- riod (Cvijic, 1908;Pamir, 1938;Perinçek, 1991;Emre et al, 1998;Gökaşan et al, 1997;Erinç, 2000;Elmas, 2003;Yigitbaş et al, 2004;Yılmaz, 2006;Gökaşan et al, 2005a). Fragments of this surface are still traceable at different elevations along the area.…”

Section: Morphology Of the Study Areamentioning

confidence: 99%

An example of secondary fault activity along the North Anatolian Fault on the NE Marmara Sea Shelf, NW Turkey

Tur

2007

Earth Planet Sp

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Seismic data on the NE Marmara Sea Shelf indicate that a NNE-SSW-oriented buried basin and ridge system exist on the sub-marine extension of the Paleozoic Rocks delimited by the northern segment of the North Anatolian Fault (NS-NAF), while seismic and multi-beam bathymetric data imply that four NW-SE-oriented strike-slip faults also exist on the shelf area. Seismic data indicate that NW-SE-oriented strike-slip faults are the youngest structures that dissect the basin-ridge system. One of the NW-SE-oriented faults (F1) is aligned with a rupture of the North Anatolian Fault (NAF) cutting the northern slope of the Ç ınarcık Basin. This observation indicates that these faults have similar characteristics with the NS-NAF along the Marmara Sea. Therefore, they may have a secondary relation to the NAF since the principle deformation zone of the NAF follows the Marmara Trough in that region. The seismic energy recorded on these secondary faults is much less than that on the NAF in the Marmara Sea. These faults may, however, produce a large earthquake in the long term.

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Evidence and implications of massive erosion along the Strait of İstanbul (Bosphorus)

Cited by 39 publications

References 19 publications

Geodynamical processes in the channel connecting the two lobes of the Large Aral Sea

Geodynamical processes in the channel connecting the two lobes of the Large Aral Sea

Water Exchange through Canal İstanbul and Bosphorus Strait

An example of secondary fault activity along the North Anatolian Fault on the NE Marmara Sea Shelf, NW Turkey

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