NHESS Natural Hazards and Earth System Sciences NHESS Nat. Hazards Earth Syst. Sci. 1684-9981 Copernicus Publications Göttingen, Germany 10.5194/nhess-12-165-2012 A proposal for a methodological approach to the characterisation of Widespread Landslide Events: an application to Southern Italy Gullà G. 1 Caloiero T. 2 Coscarelli R. 1 Petrucci O. 1 National Research Council – Research Institute for Geo-Hydrological Protection (CNR-IRPI), Cosenza, Italy National Research Council – Institute for Agricultural and Forest Systems in the Mediterranean (CNR-ISAFOM), Cosenza, Italy 17 01 2012 12 1 165 173 Copyright: © 2012 G. Gullà et al. 2012 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://nhess.copernicus.org/articles/12/165/2012/nhess-12-165-2012.html The full text article is available as a PDF file from https://nhess.copernicus.org/articles/12/165/2012/nhess-12-165-2012.pdf

This paper presents a methodological approach to both identifying and characterising Widespread Landslide Events (WLE), defined as the occurrence of several landslides through wide areas (thousands of square kilometres). This approach is based on a comparative analysis of two historical databases: a rainfall database and a landslide database, both concerning the same period. <br><br> This methodology was tested on Calabria (Southern Italy) by analysing a period of more than 80 yr. The data allowed the individuation of 25 WLEs generated by the following: (a) a single rainfall event (RE), (b) a few distinct but temporarily close REs, or (c) several consecutive REs occurring over a period of up to two months. An empirical curve, obtained by interpolating the number of landslides occurred during the WLEs and the average values of cumulative rainfall that triggered them enables the individuation of the relationship between rainfall and number of landslides. <br><br> The proposed methodological approach can be used wherever historical series of both rainfall and landslides are available. The results can be useful for monitoring the development of events and for the planning of emergency management.

 References Aguilar, E., Auer, I., Brunet, M., Peterson, T. C., and Wieringa, J.: Guidelines on Climate Metadata and Homogenization, World Climate Programme Data and Monitoring WCDMP-No.53, WMO-TD No. 1186, WMO, Geneva, 2003. Au, S. W. C.: Rain induced slope instability in Hong Kong, Eng. Geol., 51, 1–36, 1998. Barredo, J. I.: Normalised flood losses in Europe: 1970–2006, Nat. Hazards Earth Syst. Sci., 9, 97–104, http://dx.doi.org/10.5194/nhess-9-97-2009https://doi.org/10.5194/nhess-9-97-2009, 2009. Borrelli, L., Greco, R., and Gullà, G.: Weathering grade of rock masses as a predisposing factor to slope instabilities: Reconnaissance and control procedures, Geomorphology, 87, 158–175, 2007. Brunetti, M., Maugeri, M., Monti, F., and Nanni, T.: Changes in daily precipitation frequency and distribution in Italy over the last 120 years, J. Geophys. Res., 109, D05102, https://doi.org/10.1029/2003JD004296, 2004. Brunetti, M., Caloiero, T., Coscarelli, R., Gullà, G., Nanni, T. and Simolo, C.: Precipitation variability and change in the Calabria region (Italy) from a high resolution daily dataset, Int. J. Climatol., 32, 55–73, https://doi.org/10.1002/joc.2233, 2012. Caine, N.: The rainfall intensity-duration control of shallow landslides and debris flow, Geogr. Ann. A, 62, 23–27, 1980. Campbell, R.: Soil slips, debris flows and rainstorms in the Santa Monica Mountains and vicinity, Southern California, USGS Professional Paper, 851, US Government Printing Office, Washington, DC, 1975. Caloiero, D., Niccoli, R., and Reali, C.: Le precipitazioni in Calabria (1921–1980), Geodata n.&nbsp;36, CNR-IRPI, Cosenza, 1990. Caloiero, T., Coscarelli, R., Ferrari, E., and Mancini, M.: Trend detection of annual and seasonal rainfall in Calabria (Southern Italy), Int. J. Climatol., 31, 44–56, 2011. Clarizia, M., Gullà, G., and Sorbino, G.: Sui meccanismi di innesco dei soil slip, International conference Prevention of hydrogeological hazards: the role of scientific research, 1, 585–597, 1996. Corominas, J.: Landslides and climate. Keynote lecture, in: Proceedings of the 8th International Symposium on Landslides, Balkema, Cardiff, 4, 1–33, 2000. Craddock, J. M.: Methods of comparing annual rainfall records for climatic purposes, Weather, 34, 332–346, 1979. Crozier, M. J.: Landslides: causes, consequences and environment, Croom Helm, London, 1986. Della-Marta, P. M. and Wanner, H.: A method of homogenizing the extremes and mean of daily temperature measurements, J. Climate, G, 4179–4197, 2006. Devoli, G., Morales, A., and Høeg, K.: Historical landslides in Nicaragua-collection and analysis of data, Landslides, 4, 5–18, 2007. EM-DAT (The International Disaster Database): Centre for Research on the Epidemiology of Disasters (CRED), available at: <a href="http://www.emdat.be/">http://www.emdat.be/</a>, last access: June 2010. Glade, T.: Landslide hazard assessment and historical landslide data – an inseparable couple?, in: The use of historical data in natural hazard assessments, Advances of Technological and Natural Hazard Research, edited by: Glade, T., Albini, P., and Frances, F., Kluwer, 153–169, 2001. Glaser, R. and Stangl, H.: Climate and floods in central Europe since ad 1000: data, methods, results and consequences, Surv. Geophys., 25, 485–510, 2004. Gullà, G., Antronico, L., Iaquinta, P., and Terranova, O.: Susceptibility and triggering scenarios at a regional scale for shallow landslides, Geomorphology, 99, 39–58, 2008. Jones, P. D.: The instrumental data record: Its accuracy and use in attempts to identify the "CO<sub>2</sub>" signal, in: Analysis of Climate Variability, edited by: von Storch, H. and Navarra, A., Springer Verlag, Berlin, 53–76, 1995. Jones, P. D., Wigely, T. M. L., and Briffa, K. R.: Monthly mean pressure reconstructions for Europe (back to 1780) and North America (back to 1858), Tech. Note TR037, US Dept. of Energy, Washington, DC, 99 pp., 1987. Karl, T. R. and Williams, C. N.: An approach to adjusting climatological time series for discontinuous inhomogeneity, J. Clim. Appl. Meteorol., 26, 1744–1763, 1987. Keefer, D. K., Wilson, R. C., Mark, R., Brabb, E. E., Brown III, W. M., Ellen, S. D., Harp, E. L., Wieczorek, G. F., Alger, C. S., and Zatkin, R. S.: Real time landslide warning during heavy rainfall, Science, 238, 921–925, 1987. Kirschbaum, D. B., Adler, R., Hong, Y., Hill, S., and Lerner-Lam, A.: A global landslide catalog for hazard applications: method, results, and limitations, Nat. Hazards, 52, 561–575, 2009. Llasat, M. C., Barriendos, M., and Barrera, A.: The use of historical data in flood risk assessment. Application to Catalonia (NE Spain) 14th–20th centuries, View from the South, Environmental stories from the Mediterranean Word, in: CNR, edited by: Armiero, M., Istituto di Studi sulle Società del Mediterraneo, Napoli, Italy, 95–11, 2006. Mestre, O., Gruber, C., Prieur, C., Caussinus, H., and Jourdain, S.: SPLIDHOM: A method for homogenization of daily temperature observations, J. Appl. Meteor. Climatol., 50, 2343–2358, <a href="http://dx.doi.org/10.1175/2011JAMC2641.1">https://doi.org/10.1175/2011JAMC2641.1</a>, 2011. Munich Re: Natural catastrophes 2010, Munich Re, 2010, available at: <a href="http://www.munichre.com/en/homepage/default.aspx">http://www.munichre.com/en/homepage/default.aspx</a>, last access: June 2011. Ogniben, L.: Schema geologico della Calabria in base ai dati odierni, Geologica Romana, 12, 243–585, 1973. Peterson, T. C. and Easterling, D. R.: Creation of homogeneous composite climatological reference series, Int. J. Climatol., 14, 671–679, 1994. Peterson, T. C., Easterling, D. R., Karl, T. R., Groisman, P., Nicholls, N., Plummer, N., Torok, S., Auer, I., Boehm, R., Gullett, D., Vincent, L., Heino, R., Toemenvirta, H., Mestre, O., Szentimrey, T., Salinger, J., Førland, E., Hanssen-Bauer, I., Alexandersson, H., Jones, P., and Parker, D.: Homogeneity adjustments of in situ atmospheric climate data: a review, Int. J. Climatol., 18, 1493–1517, 1998. Petrucci, O. and Gullà, G.: A simplified method for landslide damage scenario assessment based on historical data, Nat. Hazards, 52, 539–560, 2010. Petrucci, O. and Pasqua, A. A.: The study of past damaging hydrogeological events for damage susceptibility zonation, Nat. Hazards Earth Syst. Sci., 8, 881–892, <a href="http://dx.doi.org/10.5194/nhess-8-881-2008">https://doi.org/10.5194/nhess-8-881-2008</a>, 2008. Petrucci, O., Polemio, M., and Pasqua, A. A.: Analysis of damaging hydro-geological events: the case of Calabria region (southern Italy), Environ. Manage., 25, 483–495, 2008. Petrucci, O., Pasqua, A. A., and Gullà, G.: Landslide damage assessment using the Support Analysis Framework (SAF): the 2009 landsliding event in Calabria (Italy), Adv. Geosci., 26, 13–17, <a href="http://dx.doi.org/10.5194/adgeo-26-13-2010">https://doi.org/10.5194/adgeo-26-13-2010</a>, 2010. Polemio, M. and Petrucci, O.: Occurrence of landslide events and the role of climate in the twentieth century in Calabria, southern Italy, Q. J. Eng. Geol. Hydroge., 43, 403–415, 2010. Sandersen, F., Bakkehøi, S., Hestnes, E., and Lied, K.: The influence of meteorological factors on the initiation of debris flows, rockfalls, rockslides and rockmass stability, Landslides, edited by: Senneset, K., Proc. of 7th Int. Symp. on Landslides, Trondheim, Rotterdam, Balkema, 1, 97–113, 1996. Schuster, R. L. and Highland, L. M.: The Third Hans Cloos Lecture, Urban landslides: socioeconomic impacts and overview of mitigative strategies, Bull. Eng. Geol. Environ., 66, 1–27, 2007. Smolka, A.: Natural disasters and the challenge of extreme events: risk management from an insurance perspective, Phil. Trans. R. Soc., 364, 2147–2165, 2006. Terranova, O., Antronico, L., and Gullà, G.: Landslide triggering scenarios in homogeneous geological contexts: The area surrounding Acri (Calabria, Italy), Geomorphology, 87, 250–267, 2007. Tortorici, L.: Lineamenti geologico-strutturali dell'Arco Calabro-Peloritano, Rendiconti della Società Italiana di Mineralogia e Petrologia, 38, 972–940, 1982. Versace, P., Ferrari, E., Gabriele, S., and Rossi, F.: Valutazione delle piene in Calabria, Geodata n.30, CNR-IRPI, Cosenza, 1989. Wieczoreck, G. F.: Effect of rainfall intensity and duration on debris flows in central Santa Cruz Mountains, California, Geol. Soc. of America, Rev. Eng. Geol., 7, 93–104, 1987. Young, K. C.: Detecting and removing inhomogeneities from long-term monthly sea level pressure time series, J. Climate, 6, 1205–1220, 1993.