We analyze borehole breakouts in 18 boreholes in the North-Sudetic Basin (NSB), located on the Lower Silesian tectonic block, to provide the first present-day stress analyses performed for the NSB. Dipmeter logs from the Upper Permian sedimentary succession showed short breakout profiles in 15 boreholes, from 458 to 1368 m depth interval. Integration of log and core interpretation revealed a close correlation between breakout occurrence and fault zones. The breakouts, although scarce, indicate consistent changes of maximum horizontal stress (S_Hmax) direction among three spatial clusters of boreholes: a prominent cluster of NNW–SSE S_Hmax direction and two subordinate ones of NW–SE and NE–SW S_Hmax directions. These stress patterns in the NSB may be placed in the tectonic stress context of the broader Sudetic region comprising the northern part of the Bohemian Massif and the Fore-Sudetic Homocline. For this area, statistics of compiled stress indicators exhibit a tri-modal S_Hmax direction distribution, quite similar to that obtained for the NSB. We proposed that stress directions and regime changes were triggered by minor fault reactivation in a transtensional stress regime, and this might be applicable also to the NSB.

我们分析了位于下西里西亚构造块上的北苏德蒂克盆地 (NSB) 的 18 个钻孔中的钻孔突破，以提供对 NSB 进行的第一次现代应力分析。来自上二叠纪沉积序列的倾角计测井显示，在 458 至 1368 m 深度间隔的 15 个钻孔中出现了短的突破剖面。测井和岩心解释的整合揭示了突破发生与断层带之间的密切相关性。突破虽然稀少，但表明三个钻孔空间簇之间最大水平应力（S _Hmax）方向的一致变化：一个突出的 NNW-SSE S _Hmax方向簇和两个从属 NW-SE 和 NE-SW S _Hmax方向簇方向。NSB 中的这些应力模式可以置于包括波西米亚地块北部和前苏地同跃层在内的更广泛的苏德蒂地区的构造应力环境中。对于该区域，编译应力指标的统计数据显示出三模态S _Hmax方向分布，与 NSB 获得的非常相似。我们提出应力方向和状态变化是由跨张应力状态中的小断层再激活触发的，这可能也适用于 NSB。