The Cheorwon area of South Korea has several records of the Quaternary faulting along the Chugaryung fault system and volcanic activity (Hantangang River Basalt). The most recent faulting event occurred along a segment of the Wangsukcheon fault (ca. 210 ka). In this study, a 5-m-deep trench was examined at the northern end of the Cheorwon Plain. The formation mechanism(s) and characteristics of local sediments as well as the timing of the Quaternary faults observed in the lower sections were analyzed. The sediments are very fine-grained, with a sand content of less than 5%. Soil wedge structures indicate that the sediments were affected by an ice-age environment. Some stratification and our analyses suggest that the sediments were formed on a floodplain. The ages of the sediments range from 150 to 130 ka, based on quartz optically-stimulated luminescence (OSL) dating. The absence of sediments younger than 100 ka is likely attributable to a change to sedimentary environments where erosion processes are dominant, with sediments being removed to the Hantangang River area. Meanwhile, a N-S-striking fault, dipping 30° eastward, cut across the sediments during 140–130 ka. This study provides important information on Quaternary sedimentary environment nearby the Hantangang River area, but also the introduction of the Quaternary fault into Chugaryung fault system, which has been lacking to data.

韩国的Chewwon地区有沿Chugaryung断层系统的第四纪断层和火山活动（Hantangang河玄武岩）的几条记录。最近的断层事件发生在旺石川断层（约210 ka）段。在这项研究中，检查了天原平原北端5米深的海沟。分析了下部沉积物的形成机理和特征，以及第四纪断层的发生时间。沉积物的颗粒非常细，含沙量小于5％。土壤楔形结构表明沉积物受冰龄环境的影响。一些分层和我们的分析表明，沉积物是在洪泛区形成的。沉积物的年龄范围为150至130 ka，基于石英的光激发发光（OSL）测年。小于100 ka的沉积物的缺乏很可能是由于沉积环境的变化，其中侵蚀过程占主导地位，沉积物被移至汉唐岗河地区。同时，向东倾斜30°的南北走向断裂在140–130 ka的时间内横穿了沉积物。该研究为汉唐岗河地区附近的第四纪沉积环境提供了重要信息，也为将第四纪断层引入楚加里格断裂系统提供了重要的资料。向东倾斜30°，在140–130 ka的时间内横穿沉积物。该研究为汉唐岗河地区附近的第四纪沉积环境提供了重要信息，也为将第四纪断层引入楚加里格断裂系统提供了重要的资料。向东倾斜30°，在140–130 ka的时间内横穿沉积物。该研究为汉唐岗河地区附近的第四纪沉积环境提供了重要信息，也为将第四纪断层引入楚加里格断裂系统提供了重要的资料。