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| Titel |
The earthquake sedimentary record in marine sediment from cores in the western part of the Marmara Sea, Turkey |
| VerfasserIn |
L. Drab, A. Hubert-Ferrari, S. Schmidt, P. Martinez |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250069584
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| Zusammenfassung |
| The North Anatolian Fault (NAF) is a 1500km long dextral strike-slip fault that
accommodates the extrusion of the Anatolian Plate away from the Arabia/Eurasia collision
zone at a rate of 20-25mm/yr. The submarine part of the North Anatolian Fault (NAF) in the
Sea of Marmara 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. Here a record of
turbidites was obtained in five cores spanning the Tekirdağ Basin, the Western High
and the Central Basin linked by the Tekirdağ Fault Segment. We characterized
earthquake-related sedimentary events by combining X-ray imagery, magnetic susceptibility,
granulometry and XRF measurements. Time constrain was obtain with 14C dating and
210Pb data. The turbidites are synchronous at different sites across the two basins
and through the structural high pointing to shaking by earthquake as a possible
triggering mechanism. In particular the M=7.4 1912 Mürefte earthquake let a distinctive
sedimentary imprint in all the studied cores. Radiocarbon dating implies a turbidite
recurrence interval of about 300 years. The low number of seismoturbidites documented
in the Central Basin compare to the Tekirdağ Basin suggests quasi-synchronous
ruptures of the Tekirdağ Segment and the adjacent Central Segment of the NAF or
a partial seismic slip on the Central Segment. Both scenarios have implications
regarding seismic hazard. Finally though we obtained a paleoseismological record
of the ruptures along the Tekirdağ Segment, further chronological constraints are
needed to better date the events and to confirm the completness of the obtained
record. |
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