Compared analyses of the seismicity cutoff depth and the corresponding BDT (brittle-ductile transition) depth obtained from rheological modelling have been performed for numerous test sites all over the Aegean Region. The major goal of this research is to determine whether the rheological transition could be effectively correlated to the seismological one, so that both information can independently contribute in determining the seismogenic layer thickness and hence in constraining the maximum width of active faults affecting a region. As concerns the seismological data, only relocated events have been considered for the purpose of this paper, included either in seismic sequences associated with a mainshock, or in datasets of background seismicity. In the same areas, we carried out rheological modelling for reconstructing the local strength envelope, focusing our attention on the BDT depth. The systematic comparison at the investigated sites indicates that 90% of the relocated seismicity always occurs within the corresponding rheological transition. Moreover, for the datasets also providing magnitudes, 99% of the total seismic scalar moment is always released above the BDT depth. Such results are verified for different tectonic regimes and geological settings, both extensional, transcurrent and compressional. The achieved results confirm that the BDT depth based on accurate strength envelopes could be considered a reliable indicator for the thickness of the seismogenic layer, thus contributing to constrain the maximum widths for active faults affecting those regions. Based on these constraints, we also applied some empirical relationships to estimate the possible maximum magnitude for seismogenic sources in correspondence of the tested sites, thus potentially improving our seismic hazard assessment analyses for these areas.

在整个爱琴海地区的许多测试地点都进行了地震活动截止深度和从流变学模型获得的相应的BDT（脆性-延性转变）深度的比较分析。这项研究的主要目的是确定流变转变是否可以有效地与地震学联系起来，以便这两种信息都可以独立地确定地震发生层的厚度，从而限制影响一个地区的活动断层的最大宽度。关于地震数据，出于本文的目的，仅考虑了重新定位的事件，包括与主震相关的地震序列或背景地震活动性数据集中。在同一地区 我们进行了流变建模以重建局部强度包络线，将注意力集中在BDT深度上。在调查地点的系统比较表明，重新定位的地震活动中有90％总是发生在相应的流变过渡内。此外，对于也提供震级的数据集，总地震标量矩的99％总是在BDT深度以上释放。对于不同的构造方式和地质环境，无论是伸展性，横流性还是压缩性，这些结果都得到了验证。所获得的结果证实，基于精确强度包络线的BDT深度可被视为震源层厚度的可靠指标，从而有助于限制影响这些区域的活动断层的最大宽度。基于这些限制，