Assessing seismic hazard of the East African Rift: a pilot study from GEM and AfricaArray

Abstract

The East African Rift System is the major active tectonic feature of the Sub-Saharan Africa region. Although the seismicity level of this divergent plate boundary can be described as moderate, several damaging earthquakes have been reported in historical times, and the seismic risk is exacerbated by the high vulnerability of the local buildings and structures. Formulation and enforcement of national seismic codes is therefore an essential future risk mitigation strategy. Nonetheless, a reliable risk assessment cannot be done without the calibration of an updated seismic hazard model for the region. A major limitation affecting the assessment of seismic hazard in Sub-Saharan Africa is the lack of basic information needed to construct source and ground motion models. The historical earthquake record is sparse, with significant variation in completeness over time across different regions. The instrumental catalogue is complete down to sufficient magnitude only for a relatively short time span. In addition, mapping of seismogenically active faults is still an on-going task, and few faults in the region are sufficiently constrained as to allow them to be directly represented within the seismic hazard model. Recent studies have identified major seismogenic lineaments, but there is substantial lack of kinematic information for intermediate-to-small scale tectonic features, information that is essential for the proper calibration of earthquake recurrence models. In this study, we use new data and Global Earthquake Model (GEM) computational tools such as the Hazard Modeller’s Toolkit and the OpenQuake engine to perform a pilot study of the seismic hazard associated with the East African Rift. The hazard model obtained has been created using the most recent information available from scientific literature, global bulletins and local earthquake catalogues, including those from AfricaArray projects. In this report, in accordance with the GEM philosophy, we describe in detail all working assumptions, main processing steps, data analyses and interpretations used for the model setup.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12

References

  1. Adams A, Nyblade A, Weeraratne D (2012) Upper mantle shear wave velocity structure beneath the East African Plateau: evidence for a deep, plateau-wide low velocity anomaly. Geophys J Int 189:123–142

    Article  Google Scholar 

  2. Akkar S, Sandikkaya MA, Bommer JJ (2014) Empirical ground-motion models for point- and extended-source crustal earthquake scenarios in Europe and the Middle East. Bull Earthq Eng 12:359–387

    Article  Google Scholar 

  3. Ambraseys NN (1991a) The Rukwa earthquake of 13 Dec. 1910 in E. Africa. Terra Nova 3:203–208

    Google Scholar 

  4. Ambraseys NN (1991b) Earthquake hazard in the Kenya Rift: the Subukia earthquake 1928. Geophys J Int 105:253–269

    Article  Google Scholar 

  5. Ambraseys NN, Adams RD (1991) Reappraisal of major African earthquakes, south of 20°N, 1900–1930. Nat Hazards 4:389–419

    Article  Google Scholar 

  6. Atkinson G, Boore D (2006) Earthquake ground-motion prediction equations for eastern North America. Bull Seismol Soc Am 96:2181–2205

    Article  Google Scholar 

  7. Ayele A, Nyblade AA, Langston CA, Cara M, Leveque J (2006) New evidence for Afro-Arabian plate separation in southern Afar. In: Yirgu G, Ebinger CJ, Maguire PKH (eds) The Afar volcanic province within the East African Rift System. Geol. Soc. Lond. Spec. Publ. 259:254–263

  8. Barth A, Wenzel F, Giardini D (2007) Frequency sensitive moment tensor inversion for light to moderate magnitude earthquakes in eastern Africa. Geophys Res Lett 34:L15302

    Article  Google Scholar 

  9. Brazier RA, Nyblade AA, Florentin J (2005) Focal mechanisms and the stress regime in NE and SW Tanzania. Geophys Res Lett 32:L14315. doi:10.1029/2005GL023156

    Article  Google Scholar 

  10. Brazier R, Miao Q, Nyblade A, Ayele A, Langston C (2008) Local magnitude scale for the Ethiopian Plateau. Bull Seismol Soc Am 98:2341–2348. doi:10.1785/0120070266

    Article  Google Scholar 

  11. Brzev S, Scawthorn C, Charleson AW, Allen L, Greene M, Jaiswal K, Silva V (2013) GEM building taxonomy version 2.0. GEM Technical Report 2013-02 V1.0.0, p 188, GEM Foundation, Pavia, Italy. doi:10.13117/GEM.EXP-MOD.TR2013.02

  12. BSSC (2003) The 2003 NEHRP Recommended provisions for new buildings and other structures. Part 1: provisions (FEMA 450), Building Seismic Safety Council. www.bssconline.org

  13. Casey M, Ebinger C, Keir D, Gloagen R, Mohamed R (2006) Strain accommodation in transitional rifts: extension by magma intrusion and faulting in the Ethiopian rift magmatic segment. In: Yirgu G, Ebinger CJ, Maguire PKH (eds) The Afar volcanic province within the East African Rift System. Geol. Soc. Lond. Spec. Publ. 259: 143–163

  14. CEN (2004) Eurocode 8: design of structures for earthquake resistance—part 1: general rules, seismic actions and rules for buildings. European Committee for Standardization, British Standard BS EN 1998-1:2004: E, 219

  15. Chesley JT, Rudnick RL, Lee CT (1999) Re-Os systematics of mantle xenoliths from the East African Rift: age, structure, and history of the Tanzanian craton. Geochim Cosmochim Acta 63:1203–1227

    Article  Google Scholar 

  16. Chiou BS-J, Youngs RR (2014) Update of the chiou and youngs NGA model for the average horizontal component of peak ground motion and response spectra. Earthq Sp 30:1117–1153

    Article  Google Scholar 

  17. Chorowicz J (2005) The East African rift system. J Afr Earth Sci 43:379–410

    Article  Google Scholar 

  18. Cotton F, Scherbaum F, Bommer JJ, Bungum H (2006) Criteria for selecting and adjusting ground motion models for specific target regions: application to central Europe and rock sites. J Seismol 10:137–156

    Article  Google Scholar 

  19. Craig TJ, Jackson JA, Priestley K, McKenzie D (2011) Earthquake distribution patterns in Africa: their relationship to variations in lithospheric and geological structure, and their rheological implications. Geophys J Int 185:403–434

    Article  Google Scholar 

  20. Dawson JB (1992) Neogene tectonics and volcanicity in the North Tanzania sector of the Gregory Rift Valley: contrasts with the Kenya sector. Tectonophysics 204:81–92

    Article  Google Scholar 

  21. Delvaux D, Barth A (2010) African stress pattern from formal inversion of focal mechanism data. Tectonophysics 482:105–128

    Article  Google Scholar 

  22. Delvaux D, Kervyn F, Macheyeki AS, Temu EB (2012) Geodynamic significance of TRM segment in East African Rift (W-Tanzania): active tectonics and paleostress in the Ufipa plateau and Rukwa basin. J Struct Geol 37:161–180

    Article  Google Scholar 

  23. Delvaux D, Mulumba J-L, Fiama Bondo S, Kervyn F, Havenith H-B (2016) Seismic hazard assessment of the Kivu rift segment based on a new seismotectonic zonation model (Western Branch, East African Rift system). J Afr Earth Sci AVCoR. doi:10.1016/j.jafrearsci.2016.10.004

    Google Scholar 

  24. d’Oreye N, Fernandez J, Gonzalez P, Kervyn F, Wauthier C, Frischknecht C, Calais E, Heleno S, Cayol V, Oyen A, Marinkovic P (2008) Systematic InSAR monitoring of African active volcanic zones: what we have learned in three years, or an harvest beyond our expectations. In: Second workshop on use of remote sensing techniques for monitoring volcanoes and seismogenic areas, USEReST 2008, 57–62

  25. Durrheim RJ (2016) African earthquakes. In: Mulugeta G, Simelane T (eds) Natural and human-induced hazards and disasters in Africa. Africa Institute of South Africa, Pretoria, pp 16–42

    Google Scholar 

  26. Edwards B, Allmann B, Fäh D, Clinton J (2010) Automatic computation of moment magnitudes for small earthquakes and the scaling of local to moment magnitude. Geophys J Int 183:407–420

    Article  Google Scholar 

  27. Ekström G, Nettles M, Dziewonski AM (2012) The global CMT project 2004–2010: centroid-moment tensors for 13,017 earthquakes. Phys Earth Planet Inter 200–201:1–9

    Article  Google Scholar 

  28. Engdahl ER, Villaseñor A (2002) Global Seismicity: 1900-1999. In: Lee WHK, Kanamori H, Jennings PC, Kisslinger C (eds) International Handbook of Earthquake and Engineering Seismology, Part A, Chapter 41. Academic Press, New York, pp 665–690

    Google Scholar 

  29. Fenton CH, Bommer JJ (2006) The MW 7.0 Machaze Mozambique earthquake of 23 February 2006. Seismol Res Lett 77:425–439

    Article  Google Scholar 

  30. Field EH, Jordan TH, Cornell CA (2003) OpenSHA—a developing community-modeling environment for seismic hazard analysis. Seismol Res Lett 74:406–419

    Article  Google Scholar 

  31. Franke D, Jokat W, Ladage S, Stollhofen H, Klimke J, Lutz R, Mahanhane ES, Ehrhardt A, Schreckenberger B (2015) The offshore East African Rift System: structural framework at the toe of a juvenile rift. Tectonics 34:2086–2104

    Article  Google Scholar 

  32. Furman TK, Kaleta J, Bryce J, Hanan B (2006) Tertiary mafic lava of Turkana, Kenya: constraints on EAST African plume structure and the occurrence of high μ volcanism in Africa. J Petrol 47:1221–1244

    Article  Google Scholar 

  33. Gardner JK, Knopoff L (1974) Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian? Bull Seismol Soc Am 64:1363–1367

    Google Scholar 

  34. Grimison NL, Chen WP (1988) Earthquakes in Davie Ridge-Madagascar region and the southern Nubian-Somalian plate boundary. J Geophys Res 93:10439–10450

    Article  Google Scholar 

  35. Gurnis M, Mittovica J, Ritsema J, Van Hest HJ (2000) Constraining mantle density structure using geological evidence of surface uplift rates: the case of African super-plume. Geochem Geophys Geosyst 1:10220

    Article  Google Scholar 

  36. Hansen S, Nyblade AA, Benoit M (2012) Mantle structure beneath Africa and Arabia from adaptively parameterized P-wave tomography: implications for the origin of Cenozoic Afro-Arabian tectonism. Earth Planet Sci Lett 319–320:23–34

    Article  Google Scholar 

  37. Hartnady CJH (1990) Seismicity and plate boundary evolution in Southeastern Africa. S Afr J Sci 93:473–484

    Google Scholar 

  38. Hartnady CJH (2002) Earthquake hazard in Africa: perspectives on the Nubia-Somalia boundary. S Afr J Sci 98:425–428

    Google Scholar 

  39. Hartnady CJH, Ben-Avrahan HZ, Rogers J (1992) Deep-ocean basin basins and submarine rises of the continental margin of south-eastern Africa: new geological research. S Afr J Sci 88:534–539

    Google Scholar 

  40. ISC (2013) International Seismological Centre, On-line Bulletin. http://www.isc.ac.uk. Int Seismol Cent, Thatcham, United Kingdom

  41. Kebede F, Kulhanek O (1991) Recent seismicity of the East African rift system and its implications. Phys Earth Planet Inter 68:259–273

    Article  Google Scholar 

  42. Keir D, Hamling J, Ayele A, Calais E, Wright T (2009) Evidence for focused magmatic accretion at segment centers from lateral dike injection captured beneath the Red Sea Rift in Afar. Geology 37:59–62

    Article  Google Scholar 

  43. Kipata ML, Delvaux D, Sebagenzi MN, Cailteux J-J, Sintubin M (2013) Brittle tectonic and stress field evolution in the Pan-African Lufilian arc and its foreland (Katanga, DRC): from orogenic compression to extensional collapse, transpressional inversion and transition to rifting. Geol Belg 16:1–17

    Google Scholar 

  44. Langston CA, Brazier RA, Nyblade AA, Owens TJ (1998) Local magnitude scale and seismicity rate for Tanzania, East Africa. Bull Seismol Soc Am 88:712–721

    Google Scholar 

  45. Lithgow-Berteloni C, Silver PG (1998) Dynamic topography, plate driving forces and the African superswell. Nature 395:269–272

    Article  Google Scholar 

  46. Lubkowski Z, Villani M, Coates K, Jirouskova N, Willis M (2014) Seismic design considerations for East Africa. In: Second European conference on earthquake engineering and seismology, 25–29 August 2014, p 14

  47. Macgregor D (2015) History of the development of the East African Rift System: a series of interpreted maps through time. J Afr Earth Sci 101:232–252

    Article  Google Scholar 

  48. Macheyeki AS, Delvaux D, De Batist M, Mruma A (2008) Fault kinematics and tectonic stress in the seismically active Manyara-Dodoma Rift segment in Central Tanzania—implications for the East African Rift. J Afr Earth Sci 51:163–188

    Article  Google Scholar 

  49. Mavonga T (2007) Some characteristics of aftershock sequences of major earthquakes from 1994 to 2002 in the Kivu Province, Western Rift Valley of Africa. Tectonophysics 439:1–12

    Article  Google Scholar 

  50. Mavonga T, Durrheim RJ (2009) Probabilistic seismic hazard assessment for the Democratic Republic of Congo and surrounding areas. S Afr J Geol 112:329–342

    Article  Google Scholar 

  51. McConnell RB (1980) A resurgent taphrogenic lineament of Precambrian origin in eastern Africa. J Geol Soc Lond 137:483–489

    Article  Google Scholar 

  52. McDougall I, Brown FH (2009) Timing of volcanism and evolution of northern Kenya Rift. Geol Mag 146:34–47

    Article  Google Scholar 

  53. McGuire RK (2004) Seismic hazard and risk analysis. Earthqu Eng Res Inst, Oakland

    Google Scholar 

  54. Midzi V, Manzunzu B (2014) Large recorded earthquakes in sub-Saharan Africa. In: Ismail-Zadeh A, Urrutia-Fucagauchi J, Kijko A, Zaliapin I (eds) Extreme natural hazards, disaster risks and societal implications. Cambridge University Press, Cambridge

    Google Scholar 

  55. Midzi V, Hlatywayo DJ, Chapola LS, Kebede F, Atakan K, Lombe DK, Turyomurugyendo G, Tugume FA (1999) Seismic hazard assessment in eastern and Southern Africa. Ann Geophys 42:1067–1083

    Google Scholar 

  56. Mulibo GD, Nyblade AA (2013) Mantle transition zone thinning beneath eastern Africa: evidence for a whole-mantle superplume structure. Geophys Res Lett 40:3562–3566

    Article  Google Scholar 

  57. Mulibo GD, Nyblade AA (2016) The seismotectonics of southeastern Tanzania: implications for the propagation of the Eastern Branch of the East African Rift. Tectonophysics 974:20–30

    Article  Google Scholar 

  58. Mulwa JK, Kimata F, Suzuki S, Kuria ZN (2014) The seismicity in Kenya (East Africa) for the period 1906–2010: a review. J Afr Earth Sci 89:72–78

    Article  Google Scholar 

  59. Nyblade AA, Langston CA (1995) East African earthquakes below 20 km depth and their implications for crustal structure. Geophys J Int 121:49–62

    Article  Google Scholar 

  60. Nyblade AA, Robinson SW (1994) The African superswell. Geophys Res Lett 21:765–768

    Article  Google Scholar 

  61. Pagani M, Monelli D, Weatherill G, Danciu L, Crowley H, Silva V, Henshaw P, Butler L, Nastasi M, Panzeri L, Simionato M, Viganò D (2014) OpenQuake-engine: an open hazard (and risk) software for the global earthquake model. Seismol Res Lett 85:692–702

    Article  Google Scholar 

  62. Petit C, Ebinger C (2000) Flexure and mechanical behaviour of cratonic lithosphere: gravity models of the East African and Baikal rifts. J Geophys Res 105:19151–19162

    Article  Google Scholar 

  63. Pezeshk S, Zandieh A, Tavakoli B (2011) Hybrid empirical ground-motion prediction equations for eastern North America using NGA models and updated seismological parameters. Bull Seismol Soc Am 101:1859–1870

    Article  Google Scholar 

  64. Pik R, Marty B, Carignan J, Lave J (2003) Stability of the upper Nile drainage network (Ethiopia) deduced from (U–Th)/He thermochronometry: implication for uplift and erosion of the Afar plume dome. Earth Planet Sci Lett 215:73–88

    Article  Google Scholar 

  65. Poggi V, Edwards B, Fäh D (2017) A comparative analysis of site-specific response spectral amplification models. Phys Chem Earth 98:16–26 (Special issue)

    Article  Google Scholar 

  66. Reiter L (1990) Earthquake hazard analysis. Columbia University Press, New York, p 254

    Google Scholar 

  67. Ritsema JH, Van Hest HJ, Woodhouse JH (1998) Complex shear wave velocity structure imaged beneath Africa and Iceland. Science 286:1925–1928

    Article  Google Scholar 

  68. Roberts EM, Stevens NJ, O’Connor PM, Dirks PHGM, Gottfried MD, Clyde WC, Armstrong RA, Kemp AIS, Hemming S (2012) Initiation of the Western Branch of the East African Rift, coeval with the eastern Branch. Nat Geosci 5:289–294

    Article  Google Scholar 

  69. Rydelek PA, Sacks JS (1989) Testing the completeness of earthquake catalogues and the hypothesis of self-similarity. Nature 337:249–251

    Article  Google Scholar 

  70. Saria E, Calais E, Stamps DS, Delvaux D, Hartnady CJH (2014) Present-day kinematics of the East African Rift. J Geophys Res 119:3584–3600. doi:10.1002/2013JB010901

    Article  Google Scholar 

  71. Shudofsky GN (1985) Source mechanisms and focal depths of East African earthquakes using the Rayleigh-wave inversion and body-wave modelling. Geophys J R Astron Soc 83:563–634

    Article  Google Scholar 

  72. Simmons NA, Forte AM, Grand SP (2007) Thermochemical structure and dynamics of the African superplume. Geophys Res Lett 34(L02301):2006G. doi:10.1029/L028009

    Google Scholar 

  73. Stamps DS, Saria E, Kreemer C (2015) Sub-Saharan Africa geodetic strain rate model 1.0. GEM Technical report

  74. Stepp JC (1971) An investigation of earthquake risk in the Puget Sound area by use of the type I distribution of largest extremes. Ph.D. thesis, Pennsylvania State University

  75. Storchak DA, Di Giacomo D, Bondár I, Engdahl ER, Harris J, Lee WHK, Villaseñor A, Bormann P (2013) Public Release of the ISC-GEM Global Instrumental Earthquake Catalogue (1900-2009). Seismol Res Lett 84:810–815

    Article  Google Scholar 

  76. Storchak DA, Di Giacomo D, Engdahl ER, Harris J, Bondár I, Lee WHK, Bormann P, Villaseñor A (2015) The ISC-GEM global instrumental earthquake catalogue (1900–2009). Introd Phys Earth Planet Int 239:48–63

    Article  Google Scholar 

  77. Studt FE, Cornet J, Buttgenbach H (1908) Carte geologique du Katanga et notes descriptive. Am Musee Congo, Ser. 2, 1

  78. Tanaka K, Horiuchi S, Sato T, Zana N (1980) The earthquake generating stresses in the Western Rift Valley of Africa. J Phys Earth 28:45–57

    Article  Google Scholar 

  79. Uhrhammer R (1986) Characteristics of Northern and Central California seismicity. Earthq Notes 57:21

    Google Scholar 

  80. USGS (2016) M5.9–22 km NE of Nsunga, Tanzania. U.S. Geological Survey—earthquake hazards Program. http://earthquake.usgs.gov/earthquakes/eventpage/us10006nkx#executive. Accessed 12 Sept 2016

  81. USNRC (2012) Practical implementation guidelines for SSHAC Level 3 and 4 hazard studies. Technical report, p 235. US Nuclear Regulatory Commission

  82. Van Stiphout T, Zhuang J, Marsan D (2012) Theme V—models and techniques for analysing seismicity. Technical report. Community online resource for statistical seismicity analysis. doi:10.5078/corssa-52382934

  83. Vilanova SP, Nemser ES, Besana-Ostman GM, Bezzeghoud M, Borges JF, Da Silveira AB, Cabral J, Carvalho J, Cunha PP, Dias RP, Madeira J, Lopes FC, Oliveira CS, Perea H, García-Mayordomo J, Wong I, Arvidsson R, Fonseca JFBD (2014) Incorporating descriptive metadata into seismic source zone models for seismic-hazard assessment: a case study of the Azores-West Iberian region. Bull Seismol Soc Am 104:1212–1229

    Article  Google Scholar 

  84. Vittori E, Delvaux D, Kervyn F (1997) Kanda fault: a major seismogenic element west of the Rukwa Rift (East Africa: Tanzania). J Geophys 24:139–153

    Google Scholar 

  85. Weatherill GA (2014a) OpenQuake hazard modeller’s toolkit—user guide. Glob Earthq Model (GEM). Technical Report. doi:10.13117/GEM.OPENQUAKE.MAN.HMTK.01

  86. Weatherill GA (2014b) OpenQuake ground motion toolkit—user guide. Glob Earthq Model (GEM). Technical Report. doi:10.13117/GEM.OPENQUAKE.MAN.GMTK.01

  87. Weatherill GA, Pagani M, Garcia J (2016) Exploring earthquake databases for the creation of magnitude-homogeneous catalogues: tools for application on a regional and global scale. Geophys J Int 206:1652–1676

    Article  Google Scholar 

  88. Weichert DH (1980) Estimation of the earthquake recurrence parameters for unequal observation periods for different magnitudes. Bull Seismol Soc Am 70:1337–1346

    Google Scholar 

  89. Woessner J, Wiemer S (2005) Assessing the quality of earthquake catalogues: estimating the magnitude of completeness and its uncertainty. Bull Seismol Soc Am 95:684–698

    Article  Google Scholar 

  90. Wolfenden E, Ebinger C, Yiirgu G, Deino A, Ayalew D (2004) Evolution of the northern Main Ethiopian Rift: birth of a triple junction. Earth Planet Sci Lett 224:213–228

    Article  Google Scholar 

  91. Worku A (2014) The status of basic design ground motion provisions in seismic design codes of Sub-Saharan African countries. J S Afr Inst Civ Eng 56:40–53

    Google Scholar 

  92. Yang Z, Chen WP (2010) Earthquakes along the East African Rift System: a multiscale, system-wide perspective. J Geophys Res 115:B12309

    Article  Google Scholar 

  93. Zana N, Wafula M, Lukaya N, Batabolo M (2004) The Kabalo earthquake in DR Congo on September 11, 1992: field observations and damages. Quelques résultats de Recherches en Géophysique. Centre de Recherches et Pédagogie appliqués (C. R. P. A), I.P.N, Kinshasa, 77–89

Download references

Acknowledgements

This study is made possible by the generous support of the American people through the United States Agency for International Development (USAID). The contents are the responsibility of GEM and do not necessarily reflect the views of USAID or the United States Government. AfricaArray projects that have provided seismicity information used for this study have been supported by the U.S. National Science Foundation. We would like to thank Dr. Duncan Macgregor for having provided the African fault database. A special thanks goes also to Dr. Dario Slejko and the anonymous reviewer for their appreciation for our work and their insightful suggestions.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Valerio Poggi.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Poggi, V., Durrheim, R., Tuluka, G.M. et al. Assessing seismic hazard of the East African Rift: a pilot study from GEM and AfricaArray. Bull Earthquake Eng 15, 4499–4529 (2017). https://doi.org/10.1007/s10518-017-0152-4

Download citation

Keywords

  • Probabilistic seismic hazard analysis
  • GMPEs
  • Uncertainty analysis
  • Earthquake engineering
  • Logic-tree