Seafloor gas seeps and sediment failures triggered by the August 17, 1999 earthquake in the Eastern part of the Gulf of İzmit, Sea of Marmara, NW Turkey

Kuşçu, İsmail; Okamura, Makoto; Matsuoka, Hiromi; Gökaşan, Erkan; Awata, Yasuo; Tur, Hüseyin; Şimşek, Mehmet; Keçer, Mustafa

doi:10.1016/j.margeo.2004.12.002

Cited by 57 publications

(28 citation statements)

References 58 publications

(77 reference statements)

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“…Helium analyses of water samples from this area sustain this suggestion by showing anomalous high 3 He values which point to an input from deepderived fluids (Holzner et al, 2005). A potential link between sub-surface structures and mass wasting was already suggested by several authors for other areas (Orange and Breen, 1992;Eichhubl et al, 2000;Kuşçu et al, 2004). Mass-wasting may be triggered by upward migration of fluids along faults resulting in a reduction in slope stability (Orange et al, 1997).…”

Section: Submarine Landslidesmentioning

confidence: 72%

Geological and morphological setting of 2778 methane seeps in the Dnepr paleo-delta, northwestern Black Sea

et al. 2006

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The Dnepr paleo-delta area in the NW Black Sea is characterized by an abundant presence of methane seeps. During the expeditions of May-June 2003 and within the EU-funded CRIMEA project, detailed multibeam, seismic and hydro-acoustic water-column investigations were carried out to study the relation between the spatial distribution of methane seeps, sea-floor morphology and sub-surface structures.2778 new methane seeps were detected on echosounding records in an area of 1540 km 2 . All seeps are located in the transition zone between the continental shelf and slope, in water depths of 66 to 825 m. The integration of the different geophysical datasets clearly indicates that methane seeps are not randomly distributed in this area, but are concentrated in specific locations.The depth limit for the majority of the detected seeps is 725 m water depth, which corresponds more or less with the stability limit for pure methane hydrate at the ambient bottom temperature (8.9 8C) in this part of the Black Sea. This suggests that, where gas hydrates are stable, they play the role of buffer for the upward migration of methane gas and thus prevent seepage of methane bubbles into the water column.Higher up on the margin, gas seeps are widespread, but accurate mapping illustrates that seeps occur preferentially in association with particular morphological and sub-surface features. On the shelf, the highest concentration of seeps is found in elongated depressions (pockmarks) above the margins of filled channels. On the continental slope where no pockmarks have been observed, seepage occurs along crests of sedimentary ridges. There, seepage is focussed by a parallel-stratified sediment cover that thins out towards the ridge crests. On the slope, seepage also appears in the vicinity of canyons (bottom, flanks and margins) or near the scarps of submarine landslides where mass-wasting breaches the fine-grained sediment cover that acts as a stratigraphic seal. The seismic data show the presence of a distinct bgas front,Q which has been used to map the depth of the free gas within the sea-floor sediments. The depth of this gas front is variable and locally domes up to the sea floor. Where the gas front approaches the seafloor, gas bubbles were detected in the water column. A regional map of the sub-surface depth of the gas front emphasises this bgas front-versus-seepQ relationship. The integration of all data sets indicates that the spatial distribution of methane seeps in the Dnepr paleo-delta is mainly controlled by the gas-hydrate stability zone as well as by stratigraphic and sedimentary factors. D

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Section: Submarine Landslidesmentioning

confidence: 72%

Geological and morphological setting of 2778 methane seeps in the Dnepr paleo-delta, northwestern Black Sea

et al. 2006

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“…These events have been tentatively correlated with earthquakes or tsunamis (Hébert et al, 2005;McHugh et al, 2006;Beck et al, 2007;McHugh et al, 2008;Çağatay et al, 2009). It is inferred that the 1999 Izmit-Kocaeli earthquake, that produced a surface rupture reaching the western end of the Gulf of Izmit , triggered mass wasting events (Polonia et al, 2002;Kuşçu et al, 2005;Çagatay et al, in press). Within the Central Basin, Beck et al (2007) identified a several meters thick homogeneous transparent acoustic layer, named "homogenite" (Kastens and Cita, 1981), and composed of very fined-grained sediment likely re-suspended after a large mass-wasting event, consequence of a tsunamigenic earthquake.…”

Section: Morpho-sedimentary Contextmentioning

confidence: 98%

Distribution, morphology and triggers of submarine mass wasting in the Sea of Marmara

et al. 2012

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An overview is given of mass wasting features along the slopes of the Sea of Marmara, Turkey, based on new data and previously published information. The Sea of Marmara is characterized by active tectonics along the North Anatolian Fault and by eustatic sea level changes controlling the connections both to the Mediterranean and Black Sea (i.e. lacustrine and marine conditions during sea-level low and high stands, respectively). High resolution bathymetric data, subsurface echo-sounder and seismic reflection profiling, seafloor visual observations, as well as stratigraphic analysis of sediment cores have been used to identify, map and date submarine slope failures and mass wasting deposits. Gravity mass movements are widespread on the steep slopes of the Sea of Marmara, and range from small scale slope failures, mainly located within the canyons, to wider unstable areas (20 to 80 km 2 ). The largest mass wasting features, i.e. the Tuzla, Ganos and Yalova complexes, have been analyzed in connection with crustal deformation. These gravitational gliding masses are probably induced by the transtensional deformation within the crust. Moreover, age determination of landslides and debris flows indicate that they were more frequent during the last transgressive phase, when the rate of terrigenous sediments supplied by the canyons to the deep basin was higher. We discuss these results taking into account activity, pre-conditioning and trigger mechanisms for slope instability with respect to tectonics and paleo-environmental changes induced by sea-level oscillations.

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“…Seepage of hydrothermal fluids along a fault located below the sea may lead to salinity or pH changes in the water during or after an earthquake (Claesson et al, 2004;Kuşçu et al, 2005). However, the local hydrogeological setting determines whether any change occurs at all (Sneed et al, 2003;Woith et al, 2003).…”

Section: Movements Of the Anatolian And The Eurasian Plates Along Thementioning

confidence: 99%

Palaeolimnology of Lake Sapanca and identification of historic earthquake signals, Northern Anatolian Fault Zone (Turkey)

Schwab

Werner

Dulski³

et al. 2009

Quaternary Science Reviews

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Lake Sapanca is located on a strand of the Northern Anatolian Fault Zone (NAFZ, Turkey), where a series of strong earthquakes (Ms > 6.0) have occurred over the past hundred years. Identifying prehistoric earthquakes in and around Lake Sapanca is key to a the better understanding of plate movements along the NAFZ. This study contributes to the development of palaeolimnological tools to identify past earthquakes in Lake Sapanca. To this end several promising proxies were investigated, specifically lithology, magnetic susceptibility, grain size (thin-section and laser analysis), geochemistry, pollen concentration, diatom assemblages, demonstrates that a combination of indicators can be used to recognize earthquakerelated event layers in cores that encompass a longer period of time.

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Seafloor gas seeps and sediment failures triggered by the August 17, 1999 earthquake in the Eastern part of the Gulf of İzmit, Sea of Marmara, NW Turkey

Cited by 57 publications

References 58 publications

Geological and morphological setting of 2778 methane seeps in the Dnepr paleo-delta, northwestern Black Sea

Geological and morphological setting of 2778 methane seeps in the Dnepr paleo-delta, northwestern Black Sea

Distribution, morphology and triggers of submarine mass wasting in the Sea of Marmara

Palaeolimnology of Lake Sapanca and identification of historic earthquake signals, Northern Anatolian Fault Zone (Turkey)

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