Preliminary slip rate estimates for the Düzce segment of the North Anatolian Fault Zone from offset geomorphic markers
- 作者：S. Pucci ; P.M. De Martini ; D. Pantosti
- 关键词：Tectonic geomorphology ; Geomorphic markers ; Slip rate ; Strike-slip ; 1999 Dü ; zce earthquake
- 刊名：Geomorphology
- 出版年：2008
- 期刊代码：31_0169555x
- 类别：soc
- 出版时间：15 May 2008
- 卷：97
- 期：3-4
- 页码：538-554
- 文件大小：5318 K
摘要
New estimates on the Quaternary slip rate of the active transform margin of North Anatolia are provided. We investigated the area struck by a Mw 7.1 earthquake on the 12th of November 1999 that ruptured the Düzce Fault segment of the North Anatolian Fault. In order to analyze the spectacular tectonically driven cumulative landforms and the drainage pattern settings, we carried out a 1:25,000-scale geological and geomorphological mapping along the fault trace. We reconstruct and describe, as offset geomorphic markers, right-hand stream deflections and fluvial terraces inset into alluvial fan deposits. Radiocarbon dating indicates that 
100 m stream deflections were built up by the last 7000 yrs of fault activity. Conversely, two documented and correlated Late Pleistocene fluvial terraces are horizontally offset by 300 and 900 m, respectively. These were dated by means of Optically Stimulated Luminescence (OSL) to 21 ka BP and 60 ka BP. Assuming a constant rate of deformation for the Düzce Fault, ages and related offsets translate to consistent slip rates that yield an average slip rate of 15.0 ± 3.2 mm/yr for the last 60 ka. Thus, the Düzce Fault importantly contributes to the North Anatolian margin deformation, suggesting a present-day partitioning of displacement rates with the Mudurnu Fault to the south and confirming its important role in the seismic hazard of the area.
100 m stream deflections were built up by the last 7000 yrs of fault activity. Conversely, two documented and correlated Late Pleistocene fluvial terraces are horizontally offset by 300 and 900 m, respectively. These were dated by means of Optically Stimulated Luminescence (OSL) to 21 ka BP and 60 ka BP. Assuming a constant rate of deformation for the Düzce Fault, ages and related offsets translate to consistent slip rates that yield an average slip rate of 15.0 ± 3.2 mm/yr for the last 60 ka. Thus, the Düzce Fault importantly contributes to the North Anatolian margin deformation, suggesting a present-day partitioning of displacement rates with the Mudurnu Fault to the south and confirming its important role in the seismic hazard of the area.