SEISMIC HAZARD ASSESSMENT IN THE GEMLIK BAY REGION FOLLOWING THE 17 AUGUST KOCAELI EARTHQUAKE

Seismic Hazard Assessment in the Gemlik Bay Region following the 17 August Kocaeli Earthquake

Bedri Alpar, Sevin Çizmeci

Istanbul University, Institute of Marine Sciences and Management, 34470 Vefa, Istanbul, TURKEY
General Directorate of Mineral Research and Exploration, Ankara, TURKEY

Abstract

Following the Kocaeli Earthquake (17 August 1999), the seismic reflection profiles gathered in the Gemlik Bay in 1984 were reinterpreted in order to identify the characteristics of the sedimentary depositional environments and their relations with the tectonic setting. A discussion followed about the implications for seismic hazard assessment in the Gemlik Bay region.

Keywords: Gemlik Bay, Marmara Sea, earthquake, seismic, deltas

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TSUNAMI GENERATION OF THE KOCAELI EARTHQUAKE (AUGUST 17 1999) IN THE IZMIT BAY; COASTAL OBSERVATIONS, BATHYMETRY AND SEISMIC DATA

Tsunami generation of the Kocaeli Earthquake (August 17th 1999) in the Izmit Bay; coastal observations, bathymetry and seismic data

Yıldız Altınok, Bedri Alpar, Şükrü Ersoy, Ahmet Cevdet Yalçıner

University of Istanbul, Engineering Faculty, Avcılar, 34850, Istanbul, TURKEY
University of Istanbul, Institute of Marine Sciences and Management, Vefa, 34470, Istanbul, TURKEY
Middle East Technical University, Dept. of Civil Engineering, 06531, Ankara, Turkey and University of South California, Department of Civil Engineering 90089-2531 USA

Abstract

In the present study, coastal field observations, detailed bathymetric data and analyses of single-channel, high resolution seismic reflection data are used to characterise tsunami generated during the Kocaeli Earthquake (August, 17th 1999) in the Izmit Bay.

Keywords: Tsunami generation, Izmit Bay, Marmara Sea, seismic

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UNDERWATER SIGNATURES OF THE KOCAELI EARTHQUAKE (AUGUST 17TH 1999)

Underwater signatures of the Kocaeli earthquake (August 17th 1999)

Bedri Alpar

University of Istanbul, Institute of Marine Sciences and Management, Vefa, 34470 Istanbul, TURKEY

Abstract

The fault rupture of the Kocaeli Earthquake ( MW  7.4, at 03:02 on August 17th, 1999) was well defined on land. In the present study, single-channel, high resolution seismic reflection data were used to characterise the underwater fault signatures of the Kocaeli Earthquake in the Izmit Bay and at the eastern Marmara Sea. Some personal opinions are also given about the speculations for a possible (<30 years) and devastating (>magnitude 8) earthquake in the Marmara Sea.

Keywords: Marmara, Izmit Bay, earthquake, seismic exploration

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A Scheme for Traffic Separation at the Izmit Bay

A scheme for traffic separation at the Izmit Bay

Hüseyin Ertan, Güler Alkan

Turkish Navy, Department of Navigation, Hydrography and Oceanography, 81647 Çubuklu, Istanbul, TURKEY
Engineering Faculty, Marine Transport and Management Engineering Department, Istanbul University, 34850 Avcılar, Istanbul, TURKEY

Abstract

The vessel traffic is heavy in the Izmit Bay which forms a water passage between the Marmara Sea and the important industrial areas of Sakarya. An investigation was carried out whether a scheme for traffic separation, such as in the Turkish Straits and in the Marmara Sea, is necessary for the Izmit Bay.

Keywords: Traffic separation scheme, Marmara Sea, Turkish straits

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SYMPTOMS OF A PROMINENT MEDITERRANEAN LAYER BLOCKAGE IN THE STRAIT OF ISTANBUL (MARCH 26-28, 1998) ON THE INTERACTIONS OF THE GOLDEN HORN ESTUARY

Symptoms of a prominent Mediterranean layer blockage in the Strait of Istanbul (March 26-28, 1998) on the interactions of the Golden Horn Estuary

Bedri Alpar, Ertugrul Dogan, Hüseyin Yüce, Hüsne Altiok, Ajun Kurter, Sabri Kara

University of Istanbul, Institute of Marine Sciences and Management, 344 70 Vefa, Istanbul, TURKEY
Department of Navigation, Hydrography and Oceanography, 81647 Çubuklu, Istanbul, TURKEY

Abstract

The main characteristics of the Golden Horn estuary are dominated by coupling with the Strait of Istanbul. Depending on the atmospheric factors and the water budget, the flows through the Strait of Istanbul are subject to many nonlinear transient variances such as temporary blocking of the flows in either direction. In the present paper, with the aid of short-term oceanographic and meteorological data, we will investigate the response of the Golden Horn to a prominent Mediterranean layer blockage, which occurred at the southern end of the Strait of Istanbul during March, 26-28th 1998.

Keywords: Strait of Istanbul, Golden Horn, Mediterranean water, oceanography, sea level, water masses, blockage, current

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INVESTIGATIONS ON WEIGHT LOSS OCCURING IN WINTER SEASON AND GROWTH OF GILTHEAD SEA BREAM (SPARUS AURATA) REARED IN THE BLACK SEA

Investigations on weight loss occuring in winter season and growth of gilthead sea bream (Sparus aurata) reared in the Black Sea

Temel Sahin, Bilal Akbulut, Muharrem Aksungur

Central Fisheries Research Institute, Şana, Trabzon, TURKEY

Abstract

In this research, weight loss occurring in winter season and growth performance of gilthead sea bream (Sparus aurata L., 1758) have been investigated in a cage on Eastern Black Sea coast. Fish (n=2590) with initial mean total length of 11.1±0.17 cm, body weight 24.4± 1.14 g, condition factor of 1.7±0.02  were stocked in a cage on  11 September  1996 and  fed by hand three times a day, up to they were satisfied. At monthly intervals, 30 fish were taken as sample and their total lengths and body weights measured to determine growth,  food conversion, feeding rates and condition factor. After 421 days at the end of the experiment, mean values of total length, body weight and condition factor were determined as 26.3±0.28 cm, 258.9±9.47 g and 1.7±0.02 respectively. It is observed that growth almost ceased after November when the  seawater temperature dropped below 16°C, the fish have lost weight between January and April, then growth rate increased as depending on rising  the seawater temperature.

Keywords: Gilthead sea bream, Sparus aurata , weight loss, growth, Black Sea

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ATYLUS MASSILENSIS BELLAN-SANTINI, 1975 (AMPHIPODA, DEXAMINIDAE) FOR THE FAUNA OF TURKISH BLACK SEA

Atylus massilensis Bellan-Santini, 1975 (Amphipoda, Dexaminidae) for the fauna of Turkish Black Sea

Murat Sezgin, Levent Bat

University of Ondokuz Mayıs, Sinop Fisheries Faculty, Division of Basic Sciences, Main Branch of Marine Biology, 57000, Sinop, TURKEY

Abstract

In this study, the characteristic features of Atylus massilensis Bellan-Santini, 1975, a new record for the Turkish fauna, are given based on the drawings made from collected specimens as well as their distribution and ecology.

Keywords: Atylus massilensis, Dexaminidae, Crustacea, Amphipoda, Black Sea

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EVOLUTION OF THE HERSEK DELTA (IZMIT BAY)

Evolution of the Hersek Delta (Izmit Bay)

Bedri Alpar, A. Cem Güneysu

University of Istanbul, Institute of Marine Sciences and Management, Vefa, 34470 Istanbul, TURKEY

Abstract

The Hersek Delta which was developed by the alluvial deposits carried by the Yalakdere River is an important morphological element in the middle of the southern coasts of the lzmit Bay. In the present study, field observations, detailed bathymetric data and analyses of single-channel, high resolution seismic reflection data are used to characterise the stratal geometry and seismic stratigraphy of the Hersek Delta. The tectonised acoustic basement (unit F) is overlain by a sedimentary cover composed of 4 main seismic units (A, B, C and D/E from top to bottom). The absence of late Pleistocene aged unit C at the eastern part of the Hersek Delta implies that the waters of the Marmara Sea could not spill over the Hersek Pass during the sea level maximum (~-60 m relative to modern sea level) occurred ~25 kyr BP. During Holocene and at present, the development of the Hersek Delta continues with positive and negative
accelerations under the control of tectonics and climatic changes.

Keywords: Hersek Delta, Izmit Bay, Marmara Sea, Plio-Quaternary, seismic stratigraphy, evolution

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TRITAETA GIBBOSA BATE (1862) (AMPHIPODA, DEXAMINIDAE) IN THE TURKISH BLACK SEA FAUNA

Tritaeta gibbosa Bate (1862) (Amphipoda, Dexaminidae) in the Turkish Black Sea fauna

Murat Sezgin

Ondokuz Mayıs University, Sinop Fisheries Faculty, Division of Basic Sciences, 57000 Sinop, TURKEY

Abstract

The present work is concerned with 1 Amphipod species (Tritaeta gibbosa Bate (1862)), obtained during a benthic sampling by diving at the Sinop Peninsula coasts at the depth of 22-31 m. in December 1997. 43 species of marine Crustacea Amphipoda are now known to occur in the Black Sea coast of Turkey. However, the Amphipod Tritaeta gibbosa Bate (1862) is new for the Black Sea of Turkish coastal waters.

Keywords: Tritaeta gibbosa, Dexarninidae, Crustacea Amphipoda, Black Sea

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RADIONUCLIDE CONCENTRATIONS IN MACROALGAE AND SEDIMENT SAMPLES FROM THE BOSPHORUS

Radionuclide concentrations in macroalgae and sediment samples from the Bosphorus

Sayhan Topçuoglu, Nurdan Güngör

Çekmece Nuclear Research and Training Center. P.O.Box 1, Atatürk Airport, 34831, Istanbul, TURKEY

Abstract

The paper reports 134Cs, 137Cs and 40K radionuclide concentrations in macroalgae and sediment samples collected from the Bosphorus of Turkey. They were determined during the period of 1989-1990. The highest accumulation of 137Cs radionuclide was found in Enteromorpha linza species. The 134Cs and 137Cs levels reached peak values in all sediment samples collected from Sarıyer. The results showed that the Sarıyer station was the most contaminated among all the stations of the Bosphorus.

Keywords: Bosphorus, radionuclide, macroalgae, sediment

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