The earthquake sedimentary record in the the Sea of Marmara, Turkey

The submarine part of the North Anatolian Fault (NAF) is a very significant hazard for
the 12 million people living in Istanbul (Turkey). An accurate seismic risk assessment
necessitates paleoseismological data, which can be retrieved in the Marmara Sea by using
sedimentary cores. We present here a record of turbidites obtained in cores spanning the
Tekirdag ̆ Basin, the Western High, the Central Basin, and the Cinarcik Basin. In the Tekirdag
and Western High the turbidites are synchronous pointing to shaking by earthquakes as a
triggering mechanism. Generally seismoturbidites in the Marmara Sea are distinguished from
other turbidites based in their large extension, their particular granulometric and their particular
geochemical characteristics. The 210Pb and 137Cs radionucleides measurements have also
shown that the M=7.4 1912 Mürefte earthquake and the M=7.3 1894 Prince's Island earthquake
have left a distinctive sedimentary imprint at the top of the studied cores. The chronology of
other seismoturbidites is built combining radiocarbon dating and secular variation patterns of
paleo-declination and paleo-inclination. Finally the obtained record is compared to the historical
seismicity record.