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| Titel |
Short-term and long-term slip rate along the westernmost segment of the North Anatolian Fault using paleoseismic trenching and drainage offsets |
| VerfasserIn |
Murat-Ersen Aksoy, Mustapha Meghraoui, Ziyadin Cakir, Mathieu Ferry, Gülsen Uçarkus |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042659
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| Zusammenfassung |
| We investigate the cumulative and co-seismic offsets of the Ganos fault, the westernmost segment of the right-lateral North Anatolian Fault System that ruptured during the 9 August 1912 Mürefte earthquake (Ms = 7.3). The earthquake size requires a minimum 120 km fault rupture length. Right-lateral coseismic offsets are measured at 45 sites along the 45-km-long onland section of the fault (from Gaziköy to Saros Bay). The maximum co-seismic slip reached 5.5 m at Güzelköy and Yörgüç and the average displacement was inferred as 2-3 m. Using paleo-channel and stream offsets combined with dated units from trenches we obtain slip rates for the Güzelköy and Yeniköy sites. At Güzelköy, two paleo-channels display 16 ± 0.5 m and 21 ± 0.5 m offset and yield 22.3 ± 0.5 mm/yr for the last ~700 years and 26.9 ± 0.5 mm/yr for the last 781 years. Furthermore, the dating of the lowermost sedimentary units of the 46 ± 1 m dextral offset stream at Yeniköy provided a maximum 17 mm/yr slip rate for the last 2840 years. Cumulative displacements determined at 69 localities and tectonic reconstructions provide insight on the long term deformation of the Ganos fault segment. A classification of the stream incisions, related offsets and correlations with climatic events deduced from Black Sea sea level curves indicate the correlations of consecutive 5 groups of deflections (from 70 to 300 m) with subsequent sea level rise periods at 4 ka, 10.2 ka, 12.5 ka, 14.5 ka and 17.5 ka. Slip rate estimations yield a constant slip rate of 17.9 mm/yr for the last 20 ka and a variable slip rate from 17.7 mm/yr to 18.9 mm/yr for the last 17.5 ka. These long term slip rates obtained from cumulative stream offsets are comparable to the paleoseismic rates (17 - 27 mm/yr) obtained for the last ~800 years. We discuss the signification of our results and their small variability in comparison with 22 - 26 mm/yr GPS velocities that suggest strain accumulation along the Marmara segment of the North Anatolian Fault. |
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