Browsing by Author "Msabi, Michael M."

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    Flood susceptibility mapping using GIS and multi-criteria decision analysis: a case of Dodoma region, central Tanzania
    (Elsevier, 2021) Msabi, Michael M.; Makonyo, Michael
    Floods have become common natural disasters that lead to devastating destruction to the infrastructure and natural environment. With the eminent climate change and weather variability, it might not be possible to prevent floods. However, flood prevention and mitigation can be facilitated by flood susceptibility mapping. Dodoma Region was selected due to its susceptibility to flash floods every year. The map presented in this paper is produced based on the analytical hierarchy process methodology which is an interactive decision-making approach under multi-criteria decision analysis. The method can check the consistency of the model obtained. A total of seven influencing factors are considered for mapping the flood susceptible areas within the Dodoma region, i.e. elevation, slope, geology, drainage density, flow accumulation, land-use/cover, and soil. This study established that around 40.27% of the region (17,073.323 km2) is under high to very high, whereas, 59.73% (24,517.679 km2) accounts for very low to moderate probability of flooding, respectively. The validation process of the analytical hierarchy process is executed based on the comparison of the historical flood locations of the different flood susceptible zones on the final map and AUC of 87.24% give a significant accuracy of the model. Therefore, the flood susceptibility map presented in this paper serves as a valuable tool for key stakeholders both state and non-state actors assessing flood risks in Dodoma region and the country at large.
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    Flood susceptibility mapping using GIS and multi-criteria decision analysis: a case of Dodoma region, central Tanzania
    (Elsevier, 2021) Msabi, Michael M.; Makonyo, Michael
    Floods have become common natural disasters that lead to devastating destruction to the infrastructure and natural environment. With the eminent climate change and weather variability, it might not be possible to prevent floods. However, flood prevention and mitigation can be facilitated by flood susceptibility mapping. Dodoma Region was selected due to its susceptibility to flash floods every year. The map presented in this paper is produced based on the analytical hierarchy process methodology which is an interactive decision-making approach under multi-criteria decision analysis. The method can check the consistency of the model obtained. A total of seven influencing factors are considered for mapping the flood susceptible areas within the Dodoma region, i.e. elevation, slope, geology, drainage density, flow accumulation, land-use/cover, and soil. This study established that around 40.27% of the region (17,073.323 km2) is under high to very high, whereas, 59.73% (24,517.679 km2) accounts for very low to moderate probability of flooding, respectively. The validation process of the analytical hierarchy process is executed based on the comparison of the historical flood locations of the different flood susceptible zones on the final map and AUC of 87.24% give a significant accuracy of the model. Therefore, the flood susceptibility map presented in this paper serves as a valuable tool for key stakeholders both state and non-state actors assessing flood risks in Dodoma region and the country at large.
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    Identification of groundwater potential recharge zones using GIS-based multi-criteria decision analysis: a case study of semi-arid midlands Manyara fractured aquifer, North-Eastern Tanzania
    (Elsevier, 2021) Makonyo, Michael; Msabi, Michael M.
    The extraction of groundwater has recently increased due to water scarcity as a result of human activities including agriculture, industrial and domestic use. This has accelerated the need to spatially identify groundwater potential zones for artificial aquifer recharge and extraction through boreholes drilling. The current study is aimed at identifying groundwater potential recharge zones (GPRZ) of semi-arid midlands Manyara fractured aquifer using Geographic Information System (GIS) and Multi-criteria Decision Analysis (MCDA) based on Analytic Hierarchy Process (AHP) technique. The study area solely depends on groundwater for human survival through deep and shallow boreholes water extraction. Eight influencing factors including aquifer lithology, slopes, land use/land cover (LULC), soil types, drainage density, geological lineament density, flow accumulation, and topographic wetness index (TWI) were determined and reclassified on a scale of 1–5 in ArcGIS 10.6 environments. These factors were weighted with the help of AHP and integrated with ArcGIS pro based on the weighted linear combination (WLC) method. The results were scaled into five recharge potential classes; very high, high, moderate, low, and very low recharge potential zones. The results indicates that about 1607 km2 (14.7%) of the study area is under very high potential recharge zones, 3982 km2 (36.43%) falls under high recharge zones, 3120 km2 (28.55%) moderate, 1658 km2 (15.17%) low and 562 km2 (5.14%) under very low recharge zone. To assess the accuracy of the result a total of 66 boreholes collected from the field were used and the Receiver Operator Characteristics (ROC) curve generated. The area under the curve (AUC) was found to be 78% signifying moderate to higher accuracy of the model. The presented results provide an inventory of information for the land, water, environmental policy maker's authorities, and other stakeholders to enhancing groundwater resource management within semi-arid midlands Manyara basement fractured aquifer of the internal drainage basin North-Eastern Tanzania.
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    Mineralogy and geochemistry of the Asanje iron ore deposit within the Mayamaya-Hombolo belt, Dodoma region, central Tanzania
    (University of Dar es Salaam, 2022) Shine, Yusto J.; Msabi, Michael M.; Seetharamaiah, Jagarlamudi
    This paper presents the mineralogy and chemical composition including iron ore impurities to ascertain its suitability for industrial applications. The Asanje iron ore deposit is hosted in Precambrian volcano-sedimentary rocks in the Mayamaya-Hombolo Belt in Dodoma region, within the Lake Nyanza Superterrane. Iron ores are found in two parallel ridges trending NW-SE. Ridge I occurs as vein and banded hematite-type ore and Ridge II as massive-type ore. A total of 24 ore samples were analysed for major and trace elements by XRF and petrographic studies by optical microscopy and XRD. The XRD results revealed that hematite and goethite are the main components and quartz is the gangue mineral in the iron ores. The XRF data shows the Fe2O3t content ranges from 20.8 to 87.3 wt% with an average of 52.7 wt%. The average concentrations in wt% of impurities such as SiO2, Al2O3, P2O5 and S are 37.9, 0.9, 1.2, and 0.2, respectively. By comparison, Ridge II has greater iron content (30.5–87.3 = Avg. 64.66 wt% Fe2O3t) than Ridge I (20.8–78.22 = Avg. 48.68 wt% Fe2O3t). Based on the chemical composition, the quality of iron ore is categorised as low to medium grade, and can be used in metallurgical and cement industries.
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    Reconnaissance exploration for gold in the Misaki area within the Iramba-Sekenke greenstone belt, central Tanzania
    (University of Dar es Salaam, 2020) Mpangile, Zortosy M; Msabi, Michael M.; Kazimoto, Emmanuel O.
    Combinations of geological, geophysical and geochemical techniques have been used to explore for gold deposits at Misaki within the Iramba-Sekenke Greenstone Belt in Singida region. The Misaki area is occupied by different rocks including homogeneous coarse-grained granite containing numerous xenoliths(>5 vol. %), tonalite, K-rich granite, pegmatite and dolerite dykes. All granitic rocks have been intruded by dolerite dykes, cut by epidote veins and are found juxtaposed to a tonalitic rock. Granitic rocks contain mainly anhedral to subhedral K-feldspar, plagioclase, quartz, biotite, hornblende, muscovite and opaque minerals, whereas tonalite contains similar minerals with relatively large amounts of plagioclase and mafic minerals (>10 wt. %; biotite, hornblende and opaque minerals) and no K-feldspar. The rocks are weakly foliated to massive and poikilitic. K-feldspar is perthitic, whereas plagioclases have cores with rim overgrowths. Chlorite, epidote and sericite in the rock formed at the expense of primary minerals under greenschist facies conditions. Geophysical datasets managed to identify lineaments that crosscut different rocks at Misaki, from which three (3) major structural trends have been recognized, which are NE-SW, NW-SE and ESE-WNW. Results from radiometric data mapped different lithological units by their different radiometric element contents (U, Th and K), distinguishing areas occupied by sediments or sedimentary rocks and those underlain by granitoid rocks. Soil geochemical survey have identified gold anomalies of up to 0.2ppm Au that in parts show strong affinity with Pb. Bismuth and arsenic were also found to be associated with Au in the soil. Gold anomalies when overlaid with magnetic lineaments indicate an association of gold with NE-SW trending lineaments. Results of this work call for a follow-up detailed geological mapping that would involve trenching and sampling of unweathered rocks,and documentation of geological structures to uncover potential gold deposits of the Misaki areawithin the Iramba-Sekenke Greenstone Belt.