Kassa Muluken
Department of Physics, College of Natural and Computational Sciences, Debre Tabor University, P.O.Box 272, Debre Tabor, Ethiopia.
Heliyon. 2025 Jan 10;11(2):e41861. doi: 10.1016/j.heliyon.2025.e41861. eCollection 2025 Jan 30.
The northwest Ethiopian plateau is one of the globe's most complex tectonic zones. Within the area, the previous geological and geophysical investigations revealed volcanism and deformation effects but did not thoroughly examine crust movement, isostatic compensation, and deformation patterns. The main focus of this study is to use high-resolution topography and gravity data to map the region's vertical tectonic stress and crustal thickness, including isostatic and gravity Moho, in order to obtain a better understanding of the tectonics of the area. Here, the Airy model is utilized to estimate the isostatic Moho, which is dependent on topography data. The regional Bouguer anomaly map is estimated using the Butterworth filter, and the resulting map is then inverted using 3D Parker-Oldenburg inversion technique to generate a gravity Moho for the area. Estimated results from power density spectrum analysis and previously published seismic data constrain the inversion outcome. The isostatic and gravity Moho estimations vary between 32.6 and 54.4 km and between 30 and 56.9 km, respectively. The Moho depth results agree with previous seismic and global crustal thickness models. Vertical tectonic stress is generated beneath the region based on isostatic and gravity Moho estimates. The results confirm that both the Blue Nile and Tana escarpments have positive vertical tectonic stress, indicating that the crust beneath isostatically readjusted. The Lake Tana and areas adjacent to the Lake Tana, including the Debre Tabor Graben, Guna, Choke, and Guguftu mountains, are characterized by negative vertical tectonic stress. This negative vertical tectonic stress agrees very well with regional geomorphic and tectonic elements of the region. The study offers in-depth understanding of the area tectonics.
埃塞俄比亚高原西北部是全球最复杂的构造带之一。在该区域内，以往的地质和地球物理调查揭示了火山活动和变形效应，但未对地壳运动、均衡补偿和变形模式进行全面研究。本研究的主要重点是利用高分辨率地形和重力数据绘制该区域的垂直构造应力和地壳厚度图，包括均衡莫霍面和重力莫霍面，以便更好地了解该地区的构造。在此，利用艾里模型估算依赖于地形数据的均衡莫霍面。使用巴特沃斯滤波器估算区域布格异常图，然后利用三维帕克 - 奥尔登堡反演技术对所得地图进行反演，以生成该区域的重力莫霍面。功率密度谱分析的估计结果和先前发表的地震数据对反演结果进行了约束。均衡莫霍面和重力莫霍面的估计值分别在32.6至54.4千米和30至56.9千米之间变化。莫霍面深度结果与先前的地震和全球地壳厚度模型一致。基于均衡莫霍面和重力莫霍面的估计，在该区域下方产生了垂直构造应力。结果证实，青尼罗河和塔纳河陡崖均具有正的垂直构造应力，表明其下方的地壳正在进行均衡调整。塔纳湖及其周边地区，包括德布雷塔博尔地堑、古纳、乔克和古古夫图山脉，具有负的垂直构造应力。这种负的垂直构造应力与该地区的区域地貌和构造要素非常吻合。该研究为深入了解该地区的构造提供了依据。
