, Volume 2, Issue 4, pp 343–357 | Cite as

Quantitative assessment of the residual risk in a rockfall protected area

  • Jordi CorominasEmail author
  • Ramon Copons
  • José Moya
  • Joan M. Vilaplana
  • Joan Altimir
  • Jordi Amigó
Original Article


Quantitative Risk Assessment (QRA) has become an indispensable tool for the management of landslide hazard and for planning risk mitigation measures. In this paper we present the evaluation of the rockfall risk at the Solà d’Andorra slope (Andorra Principality) before and after the implementation of risk mitigation works, in particular, the construction of protective fences. To calculate the risk level we have (i) identified the potential rockfall release areas, (ii) obtained the volume distribution of the falling rocks, (iii) determined the frequency of the rockfall events, and (iv) performed trajectographic analysis with a 3D numerical model (Eurobloc) that has provided both the expected travel distances and the kinetic energy of the blocks. The risk level at the developed area located at the foot of the rock cliff has been calculated taking into account the nature of the exposed elements and their vulnerability. In the Forat Negre basin, the most dangerous basin of the Solà d’Andorra, the construction of two lines of rockfall protection fences has reduced the annual probability of loss of life for the most exposed person inside the buildings, from 3.8×10−4 to 9.1×10−7 and the societal risk from 1.5×10−2 of annual probability of loss of life to 1.2×10−5.

Key words

Rockfall Quantitative risk assessment Residual risk Pyrenees Principality of Andorra 



The authors gratefully acknowledge the assistance of Antoni Díaz from Eurogeotecnica in the trajectographic analysis carried out. This work has received financial support from the Rockfor project (Contract QLK5-CT-2000-01302) funded by the European Commission from the project SGR2001-00081 funded by the DURSI. The authors are indebted to Professors Robin Fell and Christophe Bonnard who have reviewed and made several valuable suggestions to a first draft of the paper


  1. Alestalo J (1971) Dendrochronological interpretation of geomorphic processes. Fennia 105:1–140Google Scholar
  2. Bordonau J (1992) Els complexos glaciolacustres relacionats amb el darrer cicle glacial als Pirineus, Geoforma Ediciones, Logroño, 251 ppGoogle Scholar
  3. Braam RR, Weiss EEJ, Burrough PA (1987) Spatial and temporal analysis of mass movement using dendrochronology. Catena 14:573–584CrossRefGoogle Scholar
  4. Bunce CM, Cruden DM, Morgenstern RM (1997) Assessment of the hazard from rock fall on a highway. Can Geotech J 34:344–356CrossRefGoogle Scholar
  5. Caine N (1980) The rainfall intensity-duration control of shallow landslides and debris-flows. Geografiska Annaler 62A:23–27CrossRefGoogle Scholar
  6. Cannon SH (1988) Regional rainfall-threshold conditions for abundant debris-flow activity. In: Ellen SD, Wieczorek GF (eds) Landslides, floods and marine effects of the storm of January 3–5, 1982, in the San Francisco Bay region, California. U.S. Geological Survey Professional Paper, 1434, pp 35–42Google Scholar
  7. Chau KT, Wong RHC, Liu J, Lee CF (2003) Rockfall hazard analysis for Hong Kong based on rockfall inventory. Rock Mech Rock Eng 36(5):383–408CrossRefGoogle Scholar
  8. Copons R, Vilaplana JM, Altimir J, Amigó J (2000) Estimación de la eficacia de las protecciones contra la caída de bloques. Revista de Obras Públicas 3394:37–48Google Scholar
  9. Copons R, Altimir J, Amigó J, Vilaplana JM (2001) Medotología Eurobloc para el estudio y protección de cáidas de bloques rocosos. Principado de Andorra. V Simposio Nacional sobre Taludes y Laderas Inestables. Madrid 2:665–676Google Scholar
  10. Copons R (2005) Avaluació de la perillositat de caiguda de blocs a Andorra la Vella (Principat d’Andorra). Monografia del CRECIT. Ed. Centre de Recerca en Ciències de la Terra (CRECIT). Sant JuliàGoogle Scholar
  11. Copons R, Vilaplana JM, Corominas J, Altimir J, Amigó J (2005) Rockfall risk management in high-density urban areas. The Andorran experience. In: Glade T, Anderson M, Crozier MJ (eds) Landslide hazard and risk. Wiley, New York, pp 675–698Google Scholar
  12. Corominas J (1996) The angle of reach as a mobility index for small and large landslides. Can Geotech J 33:260–271Google Scholar
  13. Corominas J (2000) Landslides and climate. 8th International Symposium on Landslides. Cardiff, Keynote lectures [CD-Rom]Google Scholar
  14. Corominas J, Moya J (1999) Reconstructing recent landslide activity in relation to rainfall in the Llobregat river basin, Eastern Pyrenees, Spain. Geomorphology 30:79–93CrossRefGoogle Scholar
  15. Dorren LKA, Maier B, Putters US, Seijmonsbergen AC (2004) Combining field and modelling techniques to assess rockfall dynamics on a protection forest hisllslope in the European Alps. Geomorphology 57:151–167CrossRefGoogle Scholar
  16. Dussauge C, Helmstetter A, Grasso JR, Hantz D, Desvarreux P, Jeannin M, Giraud A (2002) Probabilistic approach to rockfall hazard assessment: potential of historical data analysis. Nat Hazards Earth Syst Sci 2:15–26CrossRefGoogle Scholar
  17. Fell R (1994) Landslide risk assessment and acceptable risk. Can Geotech J 31:261–272CrossRefGoogle Scholar
  18. Fell R, Hartford D (1997) Landslide risk management. In: Cruden D, Fell R (eds) Landslide risk assessment. Balkema, Rotterdam, pp 51–109Google Scholar
  19. Fell R, Ho KKS, Lacasse S, Leroi E (2005) A framework for landslide risk assessment and management. International Conference on Landslide Risk Assessment and Management. Vancouver, BC, CanadaGoogle Scholar
  20. Geotechnical Engineering Office (1998). Landslides and Boulder Falls from Natural Terrain: Interim Risk Guidelines. GEO Report No.75, Geotechnical Engineering Office, The Government of the Hong Kong Special Administrative RegionGoogle Scholar
  21. Hungr O (1997) Some methods of landslide hazard intensity mapping. In: Cruden D, Fell R (eds) Landslide risk assessment. Balkema, Rotterdam, pp 215–226Google Scholar
  22. Hungr O, Evans SG (1988) Engineering evaluation of fragmental rockfall hazard. In: Bonnard C (ed) 5th International symposium on landslides, Vol 1. Lausanne, pp 685–690Google Scholar
  23. Hungr O, Evans SG, Hazzard J (1999) Magnitude and frequency of rock falls and rock slides along the main transportation corridors of southwestern British Columbia. Can Geotech J 36:224–238CrossRefGoogle Scholar
  24. Hupp CR, Osterkamp WR, Thornton JL (1987) Debris-flow activity and associated hazards on Mount Shasta, northern California. United States Government Printing Office, paper 1396-B, B1–B39Google Scholar
  25. Leone F, Asté JP, Leroi E (1996) Vulnerability assessment of elements exposed to mass moving: working towards a better risk perception. In: Senneset K (ed) Landslides. Balkema, Rotterdam, pp. 263–269Google Scholar
  26. Lopez C, Ruíz J, Amigó J, Altimir J (1997) Aspectos metodológicos del diseño de sistemas de protección frente a las caídas de bloques mediante modelos de simulación cinemáticos. IV Simposio nacional sobre taludes y laderas inestables, Vol. 2. Granada, pp. 811–823Google Scholar
  27. Miller I, Miller M, (1998) John E. Freund's mathematical statistics with applications, 6th edn. Prentice Hall, Upper Saddle, NJ, 624 ppGoogle Scholar
  28. Moya J (2002) Determinación de la edad y de la periodicidad de los deslizamientos en el Prepirineo oriental Ph. D. Thesis, Unpublished, Universidad Politécnica de Catalunya. 260 p Google Scholar
  29. Noverraz F, Bonnard C (1991) L’écroulement rocheux de Randa, près de Zermatt. In Bell (ed) Proceedings 6th International Symposium on Landslides, Vol 1. Christchurch. A.A. Balkema, pp. 165—170Google Scholar
  30. Perret S, Dolf F, Kienholz H (2004) Rockfalls into forest: analysis and simulation of rockfall trajectories—considerations with respect to mountainous forests in Switzerland. Landslides 1:123–130CrossRefGoogle Scholar
  31. Rouiller JD, Marro C (1997) Application de la métodologie MATTEROCK à l’évaluation du danger lié aux falaises. Eclogae Geol Helvetiae 90:393–399Google Scholar
  32. Shroder JF (1978) Dendrogeomorphological analysis of mass movement of Table Cliffs Plateau, Utah. Quatern Res 9:168–185CrossRefGoogle Scholar
  33. Teixidó T, Palomares I, Valls P, Martinez P (2003) Prospecció sísmica a la cubeta d’Andorra la Vella-Escaldes-Engordany. Horitzó, Crecit-IEA 4:3–25. ( H4prospecciosismica.pdf)
  34. Wieczorek GF (1987) Effect of rainfall intensity and duration on debris flows in central Santa Cruz Mountains, California. Geological Society of America. Rev Eng Geol 7:93–104Google Scholar
  35. Wyllie DC, Norrish NI (1996) Stabilisation of rock sloes. In: Turner AK, Schuster RL (eds) Landslides: investigation and mitigation. Special Report 247. Transportation Research Board, National Research Council, Washington, DC, pp 474–504Google Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Jordi Corominas
    • 1
    Email author
  • Ramon Copons
    • 2
    • 3
  • José Moya
    • 1
  • Joan M. Vilaplana
    • 3
  • Joan Altimir
    • 2
  • Jordi Amigó
    • 4
  1. 1.Department of Geotechnical Engineering and GeosciencesTechnical University of Catalonia—UPC, Campus Nord UPCBarcelonaSpain
  2. 2.Euroconsult, Na Maria Plana 33, Andorra la VellaPrincipality of AndorraBarcelonaSpain
  3. 3.RISKNAT Group, Departament de Geodinàmica i Geofísica, Facultat de GeologiaUniversitat de BarcelonaBarcelonaSpain
  4. 4.Eurogeotecnica, Avda. De les Corts Catalanes 5-7BarcelonaSpain

Personalised recommendations