GIS-Based Susceptibility Mapping of the Fentale–Metehara Blisters and Blister Caves in the Main Ethiopian Rift: Implications for Their Conservation


The biggest and most spectacular blister caves in the world are found in the Fentale–Metehara area, in the Main Ethiopian Rift, where we inventoried 639 blisters and blister caves in an area of 80 sq. km straddling between the southern foot of Fentale volcano and the northern shore of Lake Beseka. The blisters were formed by a unique geological process involving up-doming of fluid-rich pyroclastic flows due to pressure of gases entrapped in the progressing flow, and subsequent breaching of some of the hollow domes. These unique geological heritages have been threatened, in some cases already destroyed, by various man-made and natural factors such as the unprecedented expansion of Lake Beseka, extensive infrastructure development (roads, railways, settlements and urbanization, and large-scale irrigation schemes), and younger fissural lava flows. In order to systematically determine the degree of threat quantitatively and qualitatively and evaluate the probability of destruction of any of the blisters and blister caves, we applied GIS-based frequency ratio model and non-hierarchical cluster analysis techniques and produced a susceptibility map of the area. The susceptibility map, validated using the degree of fitness technique, indicates that most of the blister field falls within very high to high susceptibility of destruction, implying that the destruction of most of these spectacular features is imminent particularly due to expansion of Lake Beseka and the Metehara town. This calls for concerted effort by the local authorities to devise mechanisms to protect the threatened blisters and blister caves along with mitigating the impacts of the expanding Lake Beseka. The susceptibility map will be helpful to guide and prioritize conservation efforts.

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  1. Abadi B (2007) Brittle fracture and lake level change at Beseka: Main Ethiopian Rift, Metehara area. Unpubl. MSc thesis. Addis Ababa University

  2. Abebe F (2007) Environmental analysis of the areal expansion and lake level rise of Lake Beseka. Unpubl. MSc thesis. Addis Ababa University

  3. Ayalew E (2009) Growing lake with growing problems: integrated hydrogeological investigation on Lake Beseka, Ethiopia. Unpubl. PhD thesis. Friedrich–Wilhelms–Universität Bonn. 194 pp

  4. Belay D (2017) Environmental impact analysis of infrastructures development and the Lake Beseka expansion on the integrity of the Fentale–Metehara blister caves, Main Ethiopian Rift. Unpubl. MSc thesis. Addis Ababa University. 165 pp

  5. Buxton DR (1949) Travels in Ethiopia. London

  6. Clark D, Williams MAJ (1978) Recent archaeological research in Southeastern Ethiopia (1974–1975): some preliminary results. Annales d’Ethiopie 11:19–44

    Article  Google Scholar 

  7. Corti G (2009) Continental rift evolution: from rift initiation to incipient breakup in the Main Ethiopian Rift. East Africa Earth Sci Rev 96:1–53

    Article  Google Scholar 

  8. Dinka MO (2017) Delineating the drainage structure and sources of groundwater flux for Lake Basaka, Central Rift Valley Region of Ethiopia. Water 797(9):1–19.

    Article  Google Scholar 

  9. Fell R, Corominas J, Bonnard C, Cascini L, Leroi E, Savage WZ (2008) Guidelines for landslide susceptibility, hazard and risk zoning for land use planning. Eng Geol 102:85–98

    Article  Google Scholar 

  10. Gibson IL (1974) Blister caves associated with an Ethiopian volcanic ash flow tuff. Stud Speleol 2:225–232

    Google Scholar 

  11. Goerner A, Jolie E, Gloaguen R (2009) Non-climatic growth of the saline Lake Beseka, Main Ethiopian Rift. J Arid Environ 73:287–295

    Article  Google Scholar 

  12. Grimes KG (2002) Small subcrustal lava caves: examples from Victoria, Australia. AMCS Bull 19:35–44

    Google Scholar 

  13. Harris WC (1844) The highlands of Ethiopia, Vol. 3. Longman, Brown and Longman, London

    Google Scholar 

  14. Mohr PA (1960) Report on a geological excursion through southern Ethiopia. Bull Geophys Observ Addis Ababa 3:9–20

    Google Scholar 

  15. MWR (1999) Study of Lake Beseka (Main Report, Vol. 1). Ministry of water resources, Addis Ababa 203 pp

    Google Scholar 

  16. Williams FM, Williams MAJ, Aumento F (2004) Tensional fissures and crustal extension rates in the northern part of the Main Ethiopian Rift. J Afr Earth Sci 38:183–197

    Article  Google Scholar 

  17. WWDSE (2011) Lake Beseka level rise project II. Final report. Environmental and socio-economic impact assessment. Water Works Design and Supervision Enterprise of the Federal Democratic Republic of Ethiopia. Technical report, pp 180

  18. Yilmaz I (2007) GIS based susceptibility mapping of karst depression in gypsum: a case study from Sivas basin (Turkey). Eng Geol 90:89–103

    Article  Google Scholar 

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This work was funded by the Addis Ababa University Small Research Fund Program to AA. Dilla University is acknowledged for supporting DB to conduct her MSc at Addis Ababa University within the framework of this project. The local authorities in the Metehara area are acknowledged for facilitating fieldwork.

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Correspondence to Asfawossen Asrat.

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Belay, D., Asrat, A. GIS-Based Susceptibility Mapping of the Fentale–Metehara Blisters and Blister Caves in the Main Ethiopian Rift: Implications for Their Conservation. Geoheritage 13, 15 (2021).

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  • Blister
  • Blister cave
  • Frequency ratio model
  • Susceptibility map
  • Geoheritage