Heat flow map of Africa projected from spectral analyses out of aeromagnetic research
Efficiency and you will discussion
The latest compilation away from a great geothermal potential chart off Africa constitutes a few main values. The original phase is the character of your chief sources of facts one to predict geothermal potentiality; next phase is then the fresh new preparing out-of thematic maps for each of these bits of facts. The 5 wishing thematic charts (i.elizabeth., geothermal epidermis manifestations, geological maps, flaws, seismic craft chart, and heat flow chart) were used just like the ArcGIS model enters. Every TLs was indeed inserted to the ArcGIS geodatabase and interpolated using brand new pure surrounding strategy which is good weighted-mediocre interpolation means you to makes sheer people areas as much as per section on dataset. The latest TLs was basically after that reclassified so you’re able to benim kaynaklarД±m a familiar viability size (from one in order to nine) where large pricing imply better geothermal potentiality. The newest geothermal potential varies according to new endurance beliefs of any factor, because dictated by AHP-derived weighting thinking.
The fresh geothermal body expression levels were an effective “distance to help you volcanic craft” covering and you can an excellent “distance so you’re able to very hot springs and you can geysers” layer. All these layers was separated into a couple groups. When you look at the elements close to these characteristics, a value of nine try assigned; the greater the distance in the geothermal body manifestation, the brand new less new influence, and you can, past a threshold length, a smaller worth of step one was used. Noorollahi et al. (2007) indicated that a lot of (97%) out-of geothermal wells are situated within this cuatro kilometer from sizzling hot springs in Northern The japanese. Although not, to minimize the opportunity of ignoring probably promising geothermal areas, i’ve assumed that the geothermal surface symptoms submitted was restricted so you’re able to a neighborhood of 5 because of the 5 km. Thus, distances less than 5 km (a comparable range to this employed by Yousefi et al. (2010) getting very hot springs inside the Iran) are thought as close so you’re able to an excellent geothermal ability, causing the task of one’s large property value 9 to own this parameter.
Depending on the in past times computed testing ranks of one’s indices, the new wisdom pairwise matrix is attained (find “Methodology” Section) while the lbs of each and every covering is projected (Dining table step 3)
Brand new geological maps are lithological research and “distance so you’re able to flaws” study due to the fact a couple separate GIS layers. To your lithological covering, sedimentary rocks tend to have reduced thermal conductivity viewpoints as compared to eruptive and you may cellar stones, for this reason, they are tasked a lower life expectancy worth towards the potentiality level. Eruptive and basements rocks provides large thermal conductivity and you may correspondingly highest geothermal potential (assigned due to the fact class 8 to have basement stones and you will group 9 to own volcanic rocks). From inside the geothermal portion, splits and you will problems are very important as they control the brand new subsurface course of drinks. In the earlier in the day knowledge, Noorollahi ainsi que al. (2007) learned that to 95% of geothermal wells are observed contained in this six kilometer out-of regional defects for the The japanese and you can Yousefi ainsi que al. (2010) used the same length to cultivate a beneficial geothermal capital map regarding Iran. Consequently, just like the geothermal epidermis manifestations TL more than, new “distance in order to faults” research level try quantified since the a scale out-of a few groups-metropolitan areas below 6000 m from defects was assigned the greatest worth (9).
New geophysical research are the newest “distance in order to seismic interest” covering while the “temperatures move determined regarding the CPD” coating. The “length to help you seismic interest” covering are addressed in the same way because range to help you defects layer; disturbance foci having depths less than ten kilometres was categorized to the a couple categories. Given that range regarding epicenter of quake increases (> 6000 m), the brand new influence on geothermal passion reduces, and you may, ergo, a lower class is understood. Regarding your highest heat disperse covering really worth, the greater number of geothermally encouraging a place was, and higher potentiality classes was assigned correctly.
Shortly after standardization of each and every covering to help you a scale from 1 so you can 9, the 5 standards levels can be compared (Fig. 6). The latest calculated structure proportion (CR) is equivalent to 0.1, ergo, the fresh new pairwise research matrix is actually consistent.