Journal of Seismology

, Volume 17, Issue 4, pp 1183–1205 | Cite as

An intensity database for earthquakes in South Africa from 1912 to 2011

  • V. Midzi
  • J. J. Bommer
  • F. O. Strasser
  • P. Albini
  • B. S. Zulu
  • K. Prasad
  • N. S. Flint
Original Article


A database of intensity observations from instrumentally recorded earthquakes in South Africa has been compiled as a contribution to the characterisation of seismic hazard. The database contains about 1,000 intensity data points (IDPs) that have been assigned from macroseismic observations retrieved from newspaper reports and questionnaires, and also digitised from previously published isoseismal maps. The database includes IDPs from 57 earthquakes with magnitudes in the range of M w 2.2 to 6.4, at epicentral distances up to 1,000 km. Sixteen events have 20 or more IDPs, with half of these events having more than 80 IDPs. The database is dominated by relatively low intensity values, mostly determined from human perception of shaking rather than structural damage. However, 19 IDPs correspond to intensity values greater than VI MMI-56. Using geological maps of South Africa, the sites of 60 % the IDPs were geologically classified as either ‘rock’ or ‘soil’, the uncertainty in locations precluding such a classification for the remaining data points. A few of the IDPs identified as being from soil sites appear to be strongly influenced by site effects, and these were removed from the trimmed database created for exploring ground-motion levels. The trimmed database includes 15 earthquakes which have a minimum of five useful IDPs, excluding those with intensity MMI = I and those based on a single observation. After removing such points, and those identified as clear ‘outliers’, a total of 436 useful IDPs were selected.


Intensity database Observations IDPs Macroseismic Site effects South Africa 



The authors are grateful for the important contributions made by Adri van Heerden, Zahn Nel and Sonja van Eck in proofreading IDP reports and translations services, Rebekah Singh, Valerie Nxumalo, Neo Moabi, Denver Birch, Souleyman Diop, Lindy Heath and Debbi Killian for assisting with the IDP geological site classification. We are also extremely grateful to Marinda Havenga for all the maps that she prepared for us throughout the study, to Lizelle Labuschagne for checking and editing the electronic supplementary files and to Tebogo Pule for replotting Fig. 2. We also gratefully acknowledge the invaluable work done by various individuals from GSO and CGS who gathered intensity data following earthquakes in South Africa, many of whom are indentified by citations of reports and papers herein. We also note the earlier efforts to compile intensity databases, which served as a useful reference for this work, by several people at CGS, including Mayshree Singh, Erna Hattingh, Tebogo Pule and Andrzej Kijko. Useful feedback and suggestions were also provided at various stages of the development of this work by various participants in the PSHA project for the Thyspunt nuclear site, particularly Drs. Roger Musson and Oona Scotti. We are also very grateful to Associate Editor Andrzej Kijko, Mayshree Singh and an anonymous reviewer for valuable constructive feedback on an earlier version of the paper, which helped to improve the final presentation of the work.

Supplementary material

10950_2013_9387_MOESM1_ESM.xls (4.3 mb)
ESM 1 This file contains the summary of the earthquakes in terms of the instrumental source parameters (i.e. epicentre, depth and magnitude) and a total of 1,059 associated IDPs in terms of their location in decimal degrees, their intensity values and their epicentral distances (XLS 4365 kb)
10950_2013_9387_MOESM2_ESM.xls (6.3 mb)
ESM 2 This file is similar to IDP_SummaryTable.xls, but also contains the results of the surface geology classification exercise for each IDP, where it was possible. The site classification resulted in an increase of the total number of IDPs to 1,102, as a result of 25 IDPs being split into new IDPs (XLS 6446 kb)
10950_2013_9387_MOESM3_ESM.xlsx (59 kb)
ESM 3 This file contains 15 earthquakes with 436 useful IDPs selected from the site classified database in the file IDP_SummaryTable_SiteClassified.xls (XLSX 59 kb)


  1. Allen TI, Wald DJ (2009) Evaluation of ground-motion modeling techniques for use in Global ShakeMap: a critique of instrumental ground-motion prediction equations, peak ground motion to macroseismic intensity conversions, and macroseismic intensity predictions in different tectonic settings. US Geological Survey Open-File Report 2009-1047 Google Scholar
  2. Allen TI, Wald DJ, Hotovec AJ, Lin K, Earle PS, Marano KD (2008) An Atlas of ShakeMaps for selected global earthquakes. US Geological Survey Open-File Report 2008-1236.Google Scholar
  3. Ambraseys NN (1985) Intensity-attenuation and magnitude-intensity relationships for northwest European earthquakes. Earthq Eng Struct Dyn 13:733–788CrossRefGoogle Scholar
  4. Ambraseys NN (1988) Engineering seismology. Earthq Eng Struct Dyn 17:1–105CrossRefGoogle Scholar
  5. Ambraseys NN, Adams RD (1991) Reappraisal of major African earthquakes, south of 20°N, 1900–1930. Nat Hazards 4:389–419CrossRefGoogle Scholar
  6. Astroza M, Monge J (1991) Regional seismic zonation in central Chile. Proceedings of the Fourth International Conference on Seismic Zonation, Stanford, California, 3: 487–494Google Scholar
  7. Bakun WH (2006) MMI attenuation and historical earthquakes in the Basin and Range province of western North America. Bull Seismol Soc Am 96(6):2206–2220CrossRefGoogle Scholar
  8. Bakun WH, McGarr A (2002) Differences in attenuation among the stable continental regions. Geophys Res Lett 29(23): doi: 10.1029/2002GL015457
  9. Bakun WH, Scotti O (2006) Regional intensity attenuation models for France and the estimation of magnitude and location of historical earthquakes. Geophys J Int 164(3):556–610CrossRefGoogle Scholar
  10. Bakun WH, Wentworth CM (1997) Estimating earthquake location and magnitude from seismic intensity data. Bull Seismol Soc Am 87(6):1502–1521Google Scholar
  11. Benouar D (1994) Magnitude-intensity and intensity-attenuation relationships for Atlas region and Algerian earthquakes. Earthq Eng Struct Dyn 13:717–727CrossRefGoogle Scholar
  12. Bommer JJ, Coppersmith KJ, Hattingh E, Nel AP (2013) An application of the SSHAC Level 3 process to the probabilistic seismic hazard assessment for the Thyspunt nuclear site in South Africa. Proceedings of 22 nd International Conference on Structural Mechanics in Reactor Technology (SMiRT22), San Francisco, California, 18–23 August.Google Scholar
  13. Cancani A (1904) Sur l’emploi d’une double échelle sismique des intensités, empirique et absolue. Gerlands Beitr Geophys 2:281–283Google Scholar
  14. Dangkua DT, Cramer CH (2011) Felt intensity versus instrumental ground motion: a difference between California and Eastern North America? Bull Seismol Soc Am 101(4):1847–1858CrossRefGoogle Scholar
  15. Davison C (1921) On scales of seismic intensity and on the construction of isoseismal lines. Bull Seismol Soc Am 11:95–129Google Scholar
  16. Davison C (1933) Scales of seismic intensity: supplementary paper. Bull Seismol Soc Am 23:158–166Google Scholar
  17. De Klerk WJ, du S Reed J (1988) An account of historical seismic activity in southern Africa with emphasis on the southern and eastern Cape. Albany Museum, Grahamstown, South Africa, 83 ppGoogle Scholar
  18. de Rossi MS (1883) Programma dell’Osservatorio ed Archivio Centrale Geodinamico presso il R. Comitato Geologico d’Italia. Bollettino del Vulcanismo Italiano X: 3–91.Google Scholar
  19. Delavaud E, Scherbaum F, Kuehn N, Riggelsen C (2009) Information-theoretic selection of ground-motion prediction equations for seismic hazard analysis: an applicability study using Californian data. Bull Seismol Soc Am 99(6):3248–3263CrossRefGoogle Scholar
  20. Earle PS, Wald DJ, Jaiswal KS, Allen TI, Marano KD, Hotovec AJ, Hearne MG, Fee JM (2009) Prompt Assessment of Global Earthquakes for Response (PAGER): a system for rapidly determining the impact of global earthquakes worldwide. US Geological Survey Open-File Report 2009-1131.Google Scholar
  21. Evernden JF, Thomson JM (1985) Predicting seismic intensities. In: Ziony JI (ed.) Evaluating earthquake hazards in the Los Angeles region — An earth-science perspective. US Geological Survey Professional Paper 1360, 151-202Google Scholar
  22. Fenton CH, Bommer JJ (2006) The Mw 7. Machaze, Mozambique, earthquake of 23 February 2006. Seismol Res Lett 77(4):424–437CrossRefGoogle Scholar
  23. Fernandez LM, Brandt MBC (2000) The reference spectral noise ratio method to evaluate the seismic response of a site. Soil Dyn Earthq Eng 20(5–8):381–388CrossRefGoogle Scholar
  24. Fernandez LM, Labuschagne PGA (1979) Catalogue of earthquakes in Southern Africa and surrounding oceans for 1976. Seismologic Series 8, Geological Survey of South Africa, 32 ppGoogle Scholar
  25. Fernandez LM, Labuschagne PGA (1980) Catalogue of earthquakes in Southern Africa and surrounding oceans for 1977. Seismologic Series 11, Geological Survey of South Africa, 29 ppGoogle Scholar
  26. Fernandez LM, Craill C, Molea T (1990) An investigation on the seismic intensities generated by the Transkei earthquake of 29 September 1989. Geological Survey Report No. 1990-0005, Geological Survey of South Africa, Pretoria, South Africa, 9 ppGoogle Scholar
  27. Graham G, Fernandez LM (1987) The Transkei Earthquake of 5 October 1986. Geological Survey Report No. 1987-0163. Geological Survey of South Africa, Pretoria, South Africa, 20 ppGoogle Scholar
  28. Green RWE, Bloch S (1971) The Ceres, South Africa, earthquake of September 29, 1969, I. Report on some aftershocks. Bull Seismol Soc Am 61:851–859Google Scholar
  29. Grünthal G (ed) (1998) European Macroseismic Scale 1998 (EMS-98). Cahiers du Centre Européen de Géodynamique et de Séismologie, LuxembourgGoogle Scholar
  30. Jensen BL (1991). Source parameters and seismotectonics of three earthquakes in the stable continental interior of Africa. MSc Thesis, Memphis State UniversityGoogle Scholar
  31. Joyner WB, Boore DM (1981) Peak horizontal acceleration and velocity from strong-motion records including records from the 1979 Imperial Valley, California, earthquake. Bull Seismol Soc Am 71:2011–2038Google Scholar
  32. Kagami H, Okada S, Ohta Y (1988) Versatile application of dense and precision seismic intensity data by an advanced questionnaire survey. Proceedings of the Ninth World Conference on Earthquake Engineering, Tokyo-Kyoto, VIII: 937–942Google Scholar
  33. Kästli P, Fäh D (2006) Rapid estimation of macroseismic effects and ShakeMaps using macroseismic data. Proceedings of First European Conference on Earthquake Engineering and Seismology, Geneva, Paper no. 1353.Google Scholar
  34. Keyser AW (1974) Some macroseismic observations in the meizoseismal area of the Boland earthquake of 29 September 1969 in the earthquake of 29 September 1969 in the South-western Cape Province, South Africa. Seismological Series 4, Geological Survey of South Africa, 53 ppGoogle Scholar
  35. Krige LJ (1936) The Swaziland and Fauresmith earthquakes of January, 1936. Trans Geol Soc S Afr 39:429–440Google Scholar
  36. Krige LJ, Maree BD (1951) Earthquakes in South Africa. Bulletin 20 published by the Geological Survey of South Africa, 14 pp. [published in Afrikaans 1948; English translation, 1951].Google Scholar
  37. Krige LJ, Venter FA (1933) The Zululand earthquake of the 31st December 1932. Trans Geol Soc S Afr 36:101–112Google Scholar
  38. Labuschagne PGA (1980) An intensity survey following the earthquake of 17 February 1980 in the south-eastern Transvaal. Geological survey Report No. 1980-0209, Geological Survey of South Africa.Google Scholar
  39. Labuschagne PGA, Lopez-Casado C (1980) An intensity survey following the seismic event of 6 July 1979 on the East Rand. Geological survey Report No. 1980-0069, Geological Survey of South Africa, 18 ppGoogle Scholar
  40. McLaughlin KL (1991) Maximum likelihood estimation of strong-motion attenuation relationships. Earthq Spectra 7(2):267–279CrossRefGoogle Scholar
  41. Medvedev JS (1962) Engineering seismology. Academia Nauk Press, Moscow, 260 ppGoogle Scholar
  42. Mercalli G (1902) Sulle modificazioni proposte alla scala sismica De Rossi-Forel. Boll Soc Sismol Ital 8:184–191Google Scholar
  43. Musson RMW (1986) The use of newspaper data in historical earthquake studies. Disasters 10(3):217–223CrossRefGoogle Scholar
  44. Musson RMW, Cecić I (2002) Macroseismology. In: W.H.K. Lee, H. Kanamori, P.C. Jennings and C. Kisslinger (eds.) International handbook of earthquake and engineering seismology. International Geophysics 81: Part A, 49, 807–822.Google Scholar
  45. Musson RMW, Grünthal G, Stucchi M (2010) The comparison of macroseismic intensity scales. J Seismol 14:413–428CrossRefGoogle Scholar
  46. Naude M (2007) A legacy of rondavels and rondavel houses in the northern interior of South Africa. S Afr J Art Hist 22(2):216–237Google Scholar
  47. Oliver HO (1956) South African earthquakes—January 1953 to December 1955. Trans Geol Soc S Afr 59:123–129Google Scholar
  48. Raper PE (1989) A dictionary of Southern African place names. Jonathan Ball Publishers, Johannesburg, 608 ppGoogle Scholar
  49. Richter CF (1958) Elementary seismology. W.H. Freeman, San FranciscoGoogle Scholar
  50. Scherbaum F, Delavaud E, Riggelsen C (2009) Model selection in seismic hazard analysis: an information-theoretic perspective. Bull Seismol Soc Am 99(6):3234–3247CrossRefGoogle Scholar
  51. Sieberg A (1912) Über die makroseismische Bestimmung der Erdbebenstärke. Gerlands Beitr Geophys 11:227–239Google Scholar
  52. Sieberg A (1920) Zerstörendes Beben im Oranjestaat. In: Hecker, O. (1920). Mitteilungen über Erdbeben im Jahre 1912. Hauptstation für Erdbebenforschung, früher in Straßburg, zurzeit in Jena, 26 ppGoogle Scholar
  53. Sieberg A (1923) Geologische, physikalische und angewandte Erdbebenkunde. G. Fischer, JenaGoogle Scholar
  54. Singh M, Hattingh E (2009) Short communication: collection of isoseismal maps for South Africa. Nat Hazards 50(2):403–408CrossRefGoogle Scholar
  55. Singh SK, Mena E, Castro R (1988) Some aspects of source characteristics of the 19 September 1985 Michoacan earthquake and ground motion amplification in and near Mexico City from strong motion data. Bull Seismol Soc Am 78:451–477Google Scholar
  56. Singh M, Kijko A, Durrheim R (2009) Seismotectonic models for South Africa: synthesis of geoscientific information, problems and way forward. Seismol Res Lett 80:70–80CrossRefGoogle Scholar
  57. Singh M, Kijko A, Durrheim R (2011) First order regional seismotectonic model for South Africa. Nat Hazards 59:383–400CrossRefGoogle Scholar
  58. Stafford PJ (2008) Conditional prediction of absolute durations. Bull Seismol Soc Am 98(3):1588–1594CrossRefGoogle Scholar
  59. USGS (2006) M7.0 Mozambique Earthquake of 22 February 2006. Poster, National Earthquake Information Center, US Geological SurveyGoogle Scholar
  60. Wald DJ, Quitoriano V, Dengler LA, Dewey JW (1999) Utilization of the Internet for rapid Community Intensity Maps. Seismol Res Lett 70:680–697CrossRefGoogle Scholar
  61. Wald DJ, Jaiswal KS, Marano KD, Bausch D (2009) Developing casualty and impact alert protocols based on the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system. Proceedings of the Second International Disaster Casualty Workshop, Cambridge, UK, p. 10 Google Scholar
  62. Wood HE (1913) On the occurrence of earthquakes in South Africa. Bull Seismol Soc Am 3:113–120Google Scholar
  63. Wood HO, Neumann F (1931) Modified Mercalli intensity scale of 1931. Bull Seismol Soc Am 21:277–283Google Scholar
  64. Worden CB, Gerstenberger MC, Rhoades DA, Wald DJ (2012) Probabilistic relationships between ground-motion parameters and Modified Mercalli Intensity in California. Bull Seismol Soc Am 102(1):204–221CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • V. Midzi
    • 1
  • J. J. Bommer
    • 2
  • F. O. Strasser
    • 1
  • P. Albini
    • 3
  • B. S. Zulu
    • 1
  • K. Prasad
    • 4
  • N. S. Flint
    • 5
  1. 1.Seismology Unit, Council for GeosciencePretoriaSouth Africa
  2. 2.Civil EngineeringImperial College LondonLondonUK
  3. 3.Istituto Nazionale di Geofisica e VulcanologiaMilanItaly
  4. 4.Central Regions Unit, Council for GeosciencePretoriaSouth Africa
  5. 5.Seismology UnitCouncil for GeoscienceCape TownSouth Africa

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