Documenting neotectonic instabilities and determining the style and time of deformation in the vast and difficult to access central Amazonia region is challenging. We focus on these issues by investigating a large area of the Negro River drainage basin, applying morphostructural analysis based on synthetic aperture radar data. The digital elevation models of the C-band Shuttle Radar Topography Mission and the L-band Protection System of Amazonia were used as the database. We also used subsurface magnetic information from the Earth Magnetic Anomaly Grid global model to validate the morphostructures. The results revealed NW-oriented morphostructural lineaments bounding multiple depositional valley fills. These were extensively fragmented to form regularly distributed en échelon rectangular blocks commonly offset horizontally by several kilometers. Strike-slip faults and oblique, either normal or reverse, faults are present. These structures were reactivated along the main NE- and SW-oriented regional structural trends due to N-S-oriented horizontal compression and E-W-oriented horizontal extension in the late Pleistocene and Holocene. The extensive neotectonic faulting results from the interplay of plate motion and Andean uplifting since the late Pleistocene, combined with local stresses.

中文翻译：

---

南美洲板内晚更新世-全新世应力由亚马逊河中部的构造不稳定性证明

记录新构造不稳定性并确定广阔且难以进入的亚马逊河中部地区的变形方式和时间具有挑战性。我们通过调查大面积的内格罗河流域流域来关注这些问题，应用基于合成孔径雷达数据的形态结构分析。C波段穿梭雷达地形任务和亚马逊L波段保护系统的数字高程模型被用作数据库。我们还使用来自地球磁异常网格全球模型的地下磁信息来验证形态结构。结果揭示了以 NW 为导向的形态结构轮廓，界定了多个沉积山谷填充物。这些被广泛分散以形成规则分布的梯形矩形块，通常水平偏移数公里。存在走滑断层和斜断层，无论是正断层还是反向断层。由于晚更新世和全新世的 NS 向水平压缩和 EW 向水平伸展，这些结构沿着主要的 NE 和 SW 向区域结构趋势重新激活。大范围的新构造断层是晚更新世以来板块运动和安第斯隆升相互作用以及局部应力共同作用的结果。