CONCLUDING REMARKS AND FUTURE WORKS

Main targets of MARAMARA2009 cruise have been reached. A schematic list of first results is indicated.

• Deployment of Piezometers The 5 piezometers have been successfully deployed in key sites in the Marmara Sea, Çinarcik  basin; first tests of piezometers carried out after deployment with acoustic trasponders indicates that the instruments where correctly deployed and are recording; gravity cores collected at piezo-station will be studied at the Geotechnical Lab. of IFREMER in Brest.

• Deployment of OBS The 10 OBSs where also deployed correctly at their station, as verified by tests carried out soon after deployment. Four of them have been deployed near piezometers, while the piezometer on the Darica Basin was served by the SN4'seismometer

• Medusa survey Several sites were surveyed with the MEDUSA system, including the SN4-station prior deployment, a site with the 1999 earthquake rupture visible at the seafloor and several sites potentially interesting for gas and fluid emissions. Those emissions were detected as anomalous reflections of the sonars in the water column and subsequently investigated using the CH$_4$ sensors on board of MEDUSA. First results indicate a striking correspondence between those anomalies and the CH$_4$ contents in the water column detected by the MEDUSA sensors. At each of the CH$_4$ anomaly sites, water have been also collected by means of a rubber pipe connected with the deployment cable of MEDUSA, and a pump operated from the surface. Sample will be analysed for CH$_4$ and He isotopes. All of the surveyed sites are located in the Darica basin and include a mud volcanoes field, a strike-slip fault scarp along the main strand of the NAF, and a possible chimney on top of a transpressive high.

• Deployment of the SN4 observatory

  Deployment of the SN4 station in the Darica Canyon was carried out after high resolution survey of the site using MBES and chirp-sonar. The deployment on the flat base of the canyon, indicated originally as a possible site, was discarded, due to the presence of a markedly uneven seafloor characterized by the presence of debris-flow deposits which included coarse grained material, stones and boulders. Therefore, we concentrated our attention to the fault segment just east of the canyon, and in particular to the narrow rectilinear valley that dissect the Darica basin and mark NAF trace in this area. We finally decided for a location that presented:

  1. a relatively flat bottom (at the scale of few meters);
  2. the presence of a CH4 anomaly;
  3. a shelter against fishing nets trowling;
  4. the important character of being the only fault active during the Holocene;
  5. a narrow principal displacement zone;

  After some test with acoustic transponder we were able to communicate with the SN4 station verifying its functioning and attitude. Moreover we carried high-resolution mutlibeam survey after deployment that enabled us to detect the SN-4 station at the seafloor and map its position (Fig.26)

• Geophysical data

  First results highlighted the high-resolution of the MB and the Chirp system on board of Urania that fitted perfectly the requirement of accuracy in mapping the subtle trace of active faults in the Sea of Marmara.

Analysis of the data collected during the expedition is under process, and will continue during the forthcoming several months.

No problems were encountered regarding neither the people nor the environment during the cruise.