The San Ramón Fault (SRF) runs for 30 km along the western flank of the Andes in front of the city of Santiago, Chile (33.5°S). Geological studies have highlighted the SRF role in the Neogene uplift of the Andes at this latitude, but the fault geometry at depth is not well constrained. Here we infer the structure of the sedimentary cover and bedrock up to a depth of 500 m along the SRF by integrating gravimetric, electrical resistivity, seismic, and magnetic methods. In a section crossing the central segment of the SRF, lateral variations in P wave velocity models indicate that the sedimentary cover is more deformed close to SRF scarps, while coincident low‐density and low‐resistivity zones suggest that the presence of two depocenters in the sedimentary cover below the SRF scarps. Gravimetric profiles distributed along the entire trace of the SRF show the same configuration of two depocenters, but the geometry of these depocenters is complex and varies along strike. Our findings suggest that the bedrock and sediments deformation along the SRF exhibit a complex geometry, which can be explained by the interplay of reverse and strike‐slip movements during the late Cenozoic. Based on our results, the distribution of crustal seismicity and shortening rates interpreted across the Andes, we estimated that SRF deformation represents 5–20% of the whole Andean shortening for the last 4 Ma. Using empirical length scales for crustal seismicity, this deformation pattern is consistent with a maximum earthquake magnitude in the range of 6.0–6.5 Mw.

中文翻译：

---

受地球物理方法约束的圣拉蒙断裂（智利）浅层解剖：其在安第斯变形中的作用

SanRamón断层（SRF）沿着安第斯山脉的西翼在智利圣地亚哥市（33.5°S）前方延伸30公里。地质研究强调了SRF在该纬度的安第斯山脉新近纪隆升中的作用，但深度断层的几何形状并没有受到很好的约束。在这里，我们通过结合重力法，电阻率法，地震法和磁法来推断沿SRF深度达500 m的沉积物盖层和基岩的结构。在横穿SRF中央部分的截面中，P的横向变化波速模型表明，沉积层在SRF陡坡附近变形更大，而重合的低密度和低电阻率区域表明，在SRF陡坡以下的沉积覆盖层中存在两个沉积中心。沿着SRF的整个轨迹分布的重量分布图显示了两个重心的相同配置，但是这些重心的几何形状很复杂，并且沿走向变化。我们的发现表明，沿着SRF的基岩和沉积物变形表现出复杂的几何形状，这可以用新生代晚期反向运动和走滑运动的相互作用来解释。根据我们的结果，解释了整个安第斯山脉的地壳地震活动性和缩短率的分布，我们估计SRF变形代表了最后4 Ma整个安第斯山脉缩短的5-20％。