Mozafari Nasim, Özkaymak Çağlar, Sümer Ökmen, Tikhomirov Dmitry, Uzel Bora, Yeşilyurt Serdar, Ivy-Ochs Susan, Vockenhuber Christof, Sözbilir Hasan, Akçar Naki
Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, 3012 Bern, Switzerland.
Department of Geological Engineering, Afyon Kocatepe University, Ahmet Necdet Sezer Kampusü Gazligöl Yolu, 03200 Afyonkarahisar, Turkey.
Swiss J Geosci. 2022;115(1):5. doi: 10.1186/s00015-022-00408-x. Epub 2022 Feb 17.
Western Anatolia is one of the most seismically active regions worldwide. To date, the paleoseismic history of many major faults, in terms of recurrence intervals of destructive earthquakes, their magnitude, displacement, and slip rates is poorly understood. Regional crustal extension has produced major horst-graben systems bounded by kilometer-scale normal faults locally in carbonates, along which vertical crustal displacements occurred. In this study, we explore the seismic history of western Anatolia using Cl exposure dating through study of well-preserved carbonate normal fault scarps. To accomplish this, Cl concentrations in 214 samples from fault plane transects on the Rahmiye and Ören fault scarps were measured and compared with existing Cl measurements of 370 samples on five fault scraps in western Anatolia. At least 20 seismic events have been reconstructed over the past 16 kyr. The age correlation of the seismic events implies four phases of high seismic activity in western Anatolia, at around 2, 4, 6, and 8 ka. Slips are modeled ranging between 0.6 to 4.2 m per seismic event, but are probably the result of clustered earthquakes of maximum magnitude 6.5 to 7.1. While the average slip rates have values of 0.3 to 1.9 mm/yr, incremental slip rates of the faults range greater than 0.1 to 2.2 mm/yr, showing more activity mostly through late Holocene. Our finding reveals high capability of cosmogenic Cl dating to explore seismic behavior of active faults beyond the existing earthquake records.
The online version contains supplementary material available at 10.1186/s00015-022-00408-x.
安纳托利亚西部是全球地震活动最频繁的地区之一。迄今为止，许多主要断层的古地震历史，在破坏性地震的复发间隔、震级、位移和滑动速率方面，人们了解甚少。区域地壳伸展在碳酸盐岩中局部形成了以千米级正断层为界的主要地垒-地堑系统，沿着这些断层发生了垂直地壳位移。在本研究中，我们通过对保存完好的碳酸盐正断层陡坎进行研究，利用氯暴露测年法来探究安纳托利亚西部的地震历史。为此，测量了来自拉赫米耶和厄伦断层陡坎断层面横断面的214个样本中的氯浓度，并与安纳托利亚西部五个断层陡坎上370个样本的现有氯测量值进行了比较。在过去16千年中至少重建了20次地震事件。地震事件的年龄相关性表明，安纳托利亚西部在大约2、4、6和8千年时出现了四个高地震活动阶段。每次地震事件的滑动模拟范围在0.6至4.2米之间，但可能是最大震级为6.5至7.1的成群地震的结果。虽然平均滑动速率值为0.3至1.9毫米/年，但断层的增量滑动速率范围大于0.1至2.2毫米/年，显示出主要在全新世晚期有更多活动。我们的发现揭示了宇宙成因氯测年在探索现有地震记录之外的活动断层地震行为方面的高能力。
在线版本包含可在10.1186/s00015-022-00408-x获取的补充材料。
