The Sea of Marmara is a tectonically active basin that straddles the North Anatolian Fault Zone (NAFZ), a major strike-slip fault that separates the Eurasian and Anatolian tectonic plates. The Main Marmara Fault (MMF), which is part of the NAFZ, contains an approximately 150 km long seismotectonic segment that has not ruptured since 1766. A key question for seismic hazard and risk assessment is whether or not the next rupture along this segment is likely to produce one major earthquake or a series of smaller earthquakes. Geomechanical characteristics such as along-strike variations in rock strength may provide an important control on seismotectonic segmentation. We find that variations in lithospheric strength throughout the Marmara region control the mechanical segmentation of the MMF and help explain its long-term seismotectonic segmentation. In particular, a strong crust that is mechanically coupled to the upper mantle spatially correlates with aseismic patches, where the MMF bends and changes its strike in response to the presence of high-density lower crustal bodies. Between the bends, mechanically weaker crustal domains that are decoupled from the mantle indicate a predominance of creeping. These results are highly relevant for the ongoing debate regarding the characteristics of the Marmara seismic gap, especially in view of the seismic hazard (Mw > 7) in the densely populated Marmara region.

马尔马拉海是一个构造活跃的盆地，横跨北安纳托利亚断层带 (NAFZ)，这是一条分隔欧亚和安纳托利亚构造板块的主要走滑断层。主要马尔马拉断层 (MMF) 是 NAFZ 的一部分，它包含一个大约 150 公里长的地震构造段，自 1766 年以来一直没有破裂。地震危险性和风险评估的一个关键问题是沿着该段的下一次破裂是否是可能会产生一次大地震或一系列较小的地震。地质力学特征，例如岩石强度的沿走向变化，可以为地震构造分割提供重要的控制。我们发现整个马尔马拉地区岩石圈强度的变化控制着 MMF 的机械分割，并有助于解释其长期地震构造分割。特别是，与上地幔机械耦合的坚固地壳在空间上与地震斑块相关，其中 MMF 弯曲并改变其走向以响应高密度下地壳体的存在。在弯曲之间，与地幔分离的机械强度较弱的地壳域表明蠕变占主导地位。这些结果与正在进行的关于马尔马拉地震间隙特征的辩论高度相关，特别是考虑到人口稠密的马尔马拉地区的地震危险性 (Mw > 7)。与地幔分离的机械强度较弱的地壳域表明蠕变占主导地位。这些结果与正在进行的关于马尔马拉地震间隙特征的辩论高度相关，特别是考虑到人口稠密的马尔马拉地区的地震危险性 (Mw > 7)。与地幔分离的机械强度较弱的地壳域表明蠕变占主导地位。这些结果与正在进行的关于马尔马拉地震间隙特征的辩论高度相关，特别是考虑到人口稠密的马尔马拉地区的地震危险性 (Mw > 7)。