The Sierra Chica Fault System (SCFS) is a west-vergent thrust bounding the easternmost basement uplift in the Pampean Ranges of Argentina. Neogene-Recent activity along this structure is responsible for ongoing mountain-building in the broken foreland of the Andes, some 800 km away from the Pacific-South American subduction zone. We characterize Quaternary activity along the SCFS and provide the first numerical age constraints at sites where crystalline rocks of the Sierra Chica range overthrust Quaternary sediments as recent as ~50 ka. Detailed trench logging of the deformation zone defines average slip rates along the SCFS to 0.01–0.36 mm/a over the past ~90 ka. Historical earthquakes of magnitudes ≤7.4 occur along Pampean Range faults without any primary surface ruptures. Thus, evidence for surface ruptures suggests that late Pleistocene slip along the SFCF was likely associated with prehistoric earthquakes with magnitudes >7, although the application of global scaling laws to this tectonic setting tends to underpredict seismogenic potential along the SCFS. Our study aims to highlight the challenges of evaluating the seismic hazard of a fault system that has been active during the late Quaternary, but lack diagnostic geomorphic expression of past surface ruptures. This observation underscores that caution is needed when applying global scaling laws to intracontinental deformation in the broken forelands of subduction zones.

Sierra Chica断层系统（SCFS）是西向逆冲推力，其边界是阿根廷Pampean山脉中最东端的基底隆升。沿这种结构的新近近来活动负责在安第斯山脉破碎的前陆进行不断的山区建设，该区域距太平洋-南美俯冲带约800公里。我们对沿SCFS的第四纪活动进行了特征描述，并提供了最早的年龄年龄限制，该纪要是塞拉塞卡山脉的结晶岩在大约50 ka之前推覆第四纪沉积物的位置。变形区的详细沟槽测井将过去约90 ka沿SCFS的平均滑移率定义为0.01-0.36 mm / a。沿潘庞山脉断裂发生的≤7.4级的历史地震没有任何主表面破裂。因此，表面破裂的证据表明，沿着SFCF的晚更新世滑移可能与7级以上的史前地震有关，尽管在该构造背景下应用全球尺度定律往往会低估SCFS上的震源潜力。我们的研究旨在凸显评估在第四纪后期活跃的断层系统的地震危险性的挑战，但该断层系统缺乏过去地表破裂的诊断地貌表达。该观察结果强调，当对俯冲带断裂的前陆中的洲内变形应用整体尺度定律时，需要谨慎行事。尽管将全球尺度定律应用于该构造环境往往会低估SCFS沿岸的震源潜力。我们的研究旨在凸显评估在第四纪晚期活跃的断层系统的地震危险性的挑战，但是该断层系统缺乏过去地表破裂的诊断地貌表达。该观察结果强调，当对俯冲带断裂的前陆中的洲内变形应用整体尺度定律时，需要谨慎行事。尽管将全球尺度定律应用于该构造环境往往会低估SCFS沿岸的震源潜力。我们的研究旨在凸显评估在第四纪晚期活跃的断层系统的地震危险性的挑战，但是该断层系统缺乏过去地表破裂的诊断地貌表达。该观察结果强调，当对俯冲带断裂的前陆中的洲内变形应用整体尺度定律时，需要谨慎行事。