The paleoearthquake record of the Cinarcık Segment of the North Anatolian Fault in the Marmara Sea (Turkey) and its implication regarding past historical rupture scenario across the Marmara Sea

Istanbul and its 12 million inhabitants borders the Marmara Sea, a submarine pull-apart
basin related to the North Anatolian Fault (NAF), a major strike slip fault that ruptures in
M>7 earthquakes. Constraining the recurrence rate of M>7 earthquakes that threaten the
megacity is problematic because the active faults are submarine. For assessing past
submarine earthquake ruptures of the Cinarcik Fault Segment located just south of
Istanbul, we studied two sedimentary cores and identified seismoturbidites related to
historical ruptures. Earthquake related turbidites are identified in both cores, based on
their distinctive sedimentological and geochemical signatures. The seismoturbidites
recorded in one of the core named Klg04 are inferred to record only mass wasting events
related to the rupture on the Cinarcik Segment because of its specific geomorphological
location. To constrain the seismoturbidites chronology, we combine short-lived
radionuclide, radiocarbon and paleoinclination data. The first four seismoturbidites
recorded match the 1894, 1509, 14th century and 989 historical earthquakes. The obtained
age model allows us to discuss past historical rupture scenario across the Marmara Sea.
The fact that the 1766 earthquakes are not recorded is further discussed based on new
macroseismic intensity data and sedimentary records East of the Cinarcik Basin.