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Tackling Heterogeneity in Groundwater Numerical Modeling: A Comparison of Linear and Inverse Geostatistical Approaches— Example of a Volcanic Aquifer in the East African Rift
Published in M. Thangarajan, Vijay P. Singh, Groundwater Assessment, Modeling, and Management, 2016
The study area is located in the East African Rift region, which is found in a particular geodynamic context, related to the separation of African and Arabian plates since about 30 million years ago. The East African Rift is an active continental rift zone. It includes the Main Ethiopian Rift, which continues south as the Kenyan Rift Valley. Therefore, the volcanic formations resulting from plate tectonics outcrop over a major part of the territory. The volcanic aquifer system, which is the focus of this chapter, is located in Ethiopia (Upper Awash aquifer).
Estimating Leaf Area Index and biomass of sugarcane based on Gaussian process regression using Landsat 8 and Sentinel 1A observations
Published in International Journal of Image and Data Fusion, 2023
Gebeyehu Abebe, Tsegaye Tadesse, Berhan Gessesse
The topography of the area is characterised by gentle slopes (slopes < 1%) with flood-prone plains of the Awash River (Dinka et al. 2014a). The soils of the Wonji-Shoa sugarcane plantation are of alluvial-colluvial origin developed under hot, tropical conditions. Texturally, the soil can be classified into heavy clay and light (coarse textured) soils. The heavy clay soils are the predominant soil group in the study area. The regional geology of the study area is mainly characterised by volcanic activities and rift tectonics, which are features of the main Ethiopian rift valley. Sugarcane is the dominant crop grown in the plantation, with few crotalaria and haricot beans grown on heavy clay soil during a fallow period (Dinka et al. 2014b). Currently, the Wonji-Shoa Sugar factory has a capacity of crushing 6,250 tons of sugarcane per day and producing 174,946 tons of sugar per year. In this study, the Wonji-Shoa sugarcane plantation was selected mainly due to easy access, availability of research laboratory and related facilities at the Wonji sugar research centre.
Controls of faulting on synrift infill patterns in the Eocene PY4 Sag, Pearl River Mouth Basin, South China Sea
Published in Australian Journal of Earth Sciences, 2019
J. Ge, X. Zhu, F. Yu, B. G. Jones, W. Tao
The early rift stage of PY4 Sag is characterised by a half-graben like geometry, three isolated depocentres and short low-displacement faults (Figures 10–12). As indicated by the scatter and discrete patterns of the fault displacement curve, F1 showed segmented activities with a displacement of less than 200 m during this stage (Figures 12a and 13a); this faulting pattern could be comparable to the initial rift motif proposed by Cowie et al. (2000). Due to the weak faulting, the early rift stage is associated with a low tectonic subsidence, which could be largely outpaced by the sediment supply. Therefore, the incipient PY4 Sag is related to a sediment overfilled basin (Figures 13a and 14a), as supported by the predominant coarsening-upwards pattern on the curve log in WSQ1 (Figures 3 and 9a, b). The footwall-sourced fan delta systems are primarily fed by antecedent drainages from the Dongsha Uplift (Figures 9a, b and 13a). This suggestion agrees with the opinion that the Dongsha Uplift had already formed during the Late Cretaceous and supplied abundant clastic sediment to the Eocene PRMB (Liu, Wu, & Cheng, 2011; Yi et al., 2012).
Quantitative discrimination of normal fault segment growth and its geological significance: example from the Tanan Depression, Tamtsag Basin, Mongolia
Published in Australian Journal of Earth Sciences, 2018
H. X. Wang, X. F. Fu, S. R. Liu, R. Chu, B. Liu, P. P. Shi
Segments are, however, transient features in the evolution of a rift zone, as they grow and interact, they may link to form larger structures (Dawers & Anders, 1995; Kim & Sanderson, 2005; Pollard & Aydin, 1988). Therefore, the process of interaction is a necessary step in the evolution of a rift zone over a range of scales. The main basin geometries of rift systems (half-graben or graben) are controlled by major faults (Morley, 1995), with fault segment growth linkages controlling the evolution of depocentres (half-graben or graben) (Dawers & Underhill, 2000). Transfer zones are associated with such faults as transfer zones link major boundary faults that are located on opposite sides of rifts (Gawthorpe & Hurst, 1993) and can therefore cause variations in rift segment geometry (Morley, Nelson, Patton, & Mun, 1990; Rosendahl et al., 1986). As well as on basin formation and depositional patterns (Athmer & Luthi, 2011; Gawthorpe & Hurst, 1993; Morley, 1999, 2002), transfer zones also have considerable influence on hydrocarbon migration and trapping in rift systems (Coskun, 1997; Morley et al., 1990; Peacock & Sanderson, 1994).