Marmara Demonstration Mission within ESONET
The Sea of Marmara and Istanbul area is the only one along the North Anatolian Fault system that did not experience a large earthquake during the XXth century. This heavily populated region (by more than 15 millions inhabitants) thus presents an exceptionally high earthquake risk.
The goal of the Marmara Demonstration Mission (DM) is to contribute to the establishment of optimized permanent seafloor observatory stations for earthquake monitoring, as part of ESONET NoE. The Marmara Sea offers the ideal location for seafloor seismogenic observations directed towards risk assessment. The deformation rates (20 mm/y) are very high compared to any other marine sites in Europe, resulting in active submarine processes that are measurable on short time scales. In addition, numerous fluid vents and related features have been discovered along the MS fault system. The area is thus unique to test hypothesis on the relations between strike-slip deformation, seismic activity, fluid flow and gas expulsion within the active fault zone. Better understanding of fluid-fault coupling processes may, hypothetically, lead to the recognition of earthquake precursors and also improve assessment of slope instability. Last but not least, logistics are favored by the proximity to the coastlines (only 5 to 30 km), which make cost-effective and realistic the establishment of permanent seafloor observatories.
The partner institutions involved in the project are : Ifremer, Collège de France, and CNRS/INSU in France ; INGV and ISMAR in Italy ; Istanbul Technical University (ITU) and DEU (Dokuz Eylul University, Izmir) in Turkey. Strong relations have also been established with KOERI (Kandilli observatory and Earthquake Research Institute) in Istanbul which is currently developing a project of cabled, seabottom seismometers in the Marmara Sea.
Visit the dedicated web site http://www.esonet.marmara-dm.itu.edu.tr/
Location of Nautile dive sites during the Marnaut Cruise (May 12 - June 12, 2007). Red dots indicate sites where cold seeps were found ; white dots where no cold seep was found. G and H stand for, respectively, gas bubble emissions and gas hydrates sites. Photographs illustrate some examples of the cold seeps explored with Nautile. G1 : gas bubble from tensional faults cutting the north-western escarpment of the Tekirdag basin. G2 : Black patch of reduced sediment with polychete tubes (3 cm length) and sulfide oxydizing bacterial colonies. G3 : in-situ gas sampling of the bubbles escaping from the black patch shown in G2. A1 : example of acoustic anomaly detected on the Eastern Ridge using the 38 kHz, SIMRAD EK-60 echo-sounder. H1 : Sediment corer pushed into bacterial mat on the Western Ridge, where hydrocarbon traces and gas hydrates (H2) were found