The 30-km-long Middle Kedrovaya (MK) fault, on the northwestern flank of Lake Baikal, is one of the most impressive late Quaternary seismogenic structures in the Baikal rift. In places, surface fault scarps expose striated bedrock fault planes and offer some opportunities to examine the faulting history. Using cosmogenic ¹⁰Be exposure dating, we measured the exposure ages of one of the MK scarps (54.44630°N, 108.51524°E, elevation 985 m). This ~12-m-high normal fault scarp is composed of cataclasites in early Proterozoic granitoids of the Irel complex. We analyzed 12 of 18 samples, collected every 0.5 m, from 0.45 m above the toe of the exposed fault plane, which dips 55° in its lower half (samples 1–6) and 45° in upper half (samples 7–12). Exposure ages are the following from the toe upward: sample 1, 2.26 ± 0.53 ka; 2, 1.54 ± 0.55 ka; 3, 0.80 ± 0.55 ka; 5, 1.44 ± 0.55 ka; 6, 2.13 ± 0.62 ka; 8, 1.45 ± 0.48 ka; and 9, 1.40 ± 0.52 ka. The relationship between the oldest calculated ages (samples 1 and 6) and the relative sampling height along the scarp suggests that a recent surface-rupture event with a vertical component of 2.05 m (i.e. net slip of 2.5 m) occurred on the cliff ~2.2 ± 0.6 ka. Striations on the fault plane in the sampling points 1 and 6, as well a close date of 2145–2463 cal years BP calculated from radiocarbon age of a paleoseismic rupture within the Cape Shartly, ~62 km further southwestward, support this interpretation. The close ages assume that the dated deformations were related to a single M_w = 7.4 earthquake, the coseismic effects of which extended at least 82 km (the rupture length between the Cape Shartly and the NNE termination of the MK paleoseismic rupture zone). A more concentrated age mode of about 1.46 ± 0.53 ka (samples 2, 5, 8 and 9), which is in an incorrect stratigraphic order in reference to the older ages, is assumed to result from local erosion or partial shielding. Cosmogenic dating of fault scarps and seismogenic landslide scarps in bedrock potentially offers an independent method of reconstructing the late Quaternary paleoseismology of the northwestern flank of Lake Baikal.

贝加尔湖西北侧的30公里长的中科德罗瓦亚（MK）断裂是贝加尔湖裂谷中最令人印象深刻的第四纪晚期地震成因之一。在某些地方，地表断层陡坡暴露出条纹状的基岩断层，并提供了一些机会来检查断层历史。使用宇宙宇宙¹⁰在暴露定年之前，我们测量了一种MK陡角的暴露年龄（54.44630°N，108.51524°E，高程985 m）。约12米高的正常断层陡坡是由Irel复合体的早期元古代花岗岩中的裂殖体组成的。我们分析了18个样本中的12个，每0.5 m采集一次，从裸露的断层脚趾上方0.45 m开始，其下半部倾斜55°（样本1-6），上半部倾斜45°（样本7-12） 。从脚趾向上的暴露年龄如下：样品1，2.26±0.53 ka; 2，1.54±0.55 ka; 3、0.80±0.55ka；5，1.44±0.55 ka; 6、2.13±0.62ka；8、1.45±0.48ka；和9，1.40±0.52 ka。最古老的计算年龄（样本1和6）与沿陡坡的相对样本高度之间的关系表明，最近的地面破裂事件的垂直分量为2.05 m（即净滑移为2）。5 m）发生在悬崖上〜2.2±0.6 ka。采样点1和6的断层平面上的条纹，以及从西南偏远约62 km的海角Shartly内古地震破裂的放射性碳年龄计算得出的BP结束日期2145–2463 cal BP，都支持这种解释。接近年龄假定过时的变形与单个M _w  = 7.4级地震，其同震作用至少延伸了82 km（在Shartly角和MK古地震破裂带的NNE终端之间的破裂长度）。假定较集中的年龄模式约为1.46±0.53 ka（样本2、5、8和9），这是相对于较早年龄而言不正确的地层顺序，其原因是局部侵蚀或部分屏蔽。基岩中断层赤道和地震成因的滑坡赤道的宇宙成因年代可能为重建贝加尔湖西北侧晚第四纪古地震学提供一种独立的方法。