Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 8 5 2008 10.5194/nhess-8-973-2008 http://www.nat-hazards-earth-syst-sci.net/8/973/2008/ http://www.nat-hazards-earth-syst-sci.net/8/973/2008/nhess-8-973-2008.html http://www.nat-hazards-earth-syst-sci.net/8/973/2008/nhess-8-973-2008.pdf 973 976 2008-09-01 Investigating non-uniform scaling behaviour in temporal fluctuations of seismicity L. Telesca luciano.telesca@imaa.cnr.it M. Lovallo Dipartimento Infrastrutture e Mobilità, Ufficio Difesa del Suolo, Regione Basilicata, Potenza, Italy Scaling behaviour in nonstationary time series can be successfully detected using the detrended fluctuation analysis (DFA). Observational time series often do not show a stable and uniform scaling behaviour, given by the presence of a unique clear scaling region. The deviations from uniform power-law scaling, which suggest the presence of changing dynamics in the system under study, can be identified and quantified using an appropriate instability index. In this framework, the scaling behaviour of the 1981–2007 seismicity in Umbria-Marche (central Italy), which is one of the most seismically active areas in Italy, was investigated. Significant deviations from uniform power-law scaling in the seismic temporal fluctuations were revealed mostly linked with the occurrence of rather large earthquakes or seismic clusters. Allan, D. W.: Statistics of Atomic Frequency Standards, Proc. IEEE, 54, 221–230, 1966. Ashkenazy, Y., Havlin, S., Ivanov, P. Ch., Peng, C.-K., Schulte-Frohlinde, V., and Stanley, H. E.: Magnitude and sign scaling in power-law correlated time series, Physica A, 323, 19–41, 2003. Boncio, P. and Lavecchia, G.: A structural model for active extension in Central Italy, J. Geodyn., 29, 233–244, 2000. Calamita, F., Coltorti, M., Piccinini, D., Pierantoni, P. P., Pizzi, A., Ripepe, M., Scisciani, V., and Turco, E.: Quaternary faults and seismicity in the Umbro-Marchean Apennines (Central Italy): evidence from the 1997 Colfiorito earthquake, J. Geodyn., 29, 245–264, 2000. Cinti, F. R., Cucci, L., Marra, F., and Montone, P.: The 1997 Umbria-Marche earthquakes (Italy): relation between the surface tectonic breaks and the area of deformation, J. Seismol., 4, 333–343, 2000. Cox, D. R. and Isham, V.: Point Processes, Chapman and Hall, London, 1980. Di Giovambattista, R. and Tyupkin, Y. S.: Spatial and temporal distribution of seismicity before the Umbria-Marche September 26, 1997 earthquakes, J. Seismol., 4, 589–598, 2000. Esposito, E., Porfido, S., Simonelli, A. L., Mastrolorenzo, G., and Iaccarino, G.: Landslides and other surface effects induced by the 1997 Umbria-Marche seismic sequence, Eng. Geol., 58, 353–376, 2000. Galadini, F., Galli, P., Leschiutta, I., Monachesi, G., and Stucchi, M.: Active tectonics and seismicity in the area of the 1997 earthquake sequence in central Italy: A short review, J. Seismol., 3, 167–175, 1999. Kuksenko, V., Tomilin, N., and Chmel, A.: The rock fracture experiment with a drive control: A spatial aspect, Tectonophysics, 431, 123–129, 2007. Lavecchia, G., Brozzetti, F., Barchi, M., Menichetti, M., and Keller, J. V. A.: Seismotectonic zoning in east-central Italy deduced from an analysis of the Neogene to Present deformations and related stress fields, Geol. Soc. Am. Bull., 106, 1107–1120, 1994. Lowen, S. B. and Teich, M. C.: Estimation and Simulation of Fractal Stochastic Point Processes, Fractals, 3, 183–210, 1995. Peng, C.-K., Havlin, S., Stanley, H. E., and Goldberger, A. L.: Quantification of scaling exponents and crossover phenomena in nonstationary heartbeat time series, Chaos, 5, 82–87, 1995. Ripepe, M., Piccinini, D., and Chiaraluce, L.: Foreshock sequence of September 26th, 1997 Umbria-Marche earthquakes, J. Seismol., 4, 387–399, 2000. Telesca, L., Lapenna, V., and Macchiato, M.: Spatial variability of time-correlated behaviour in Italian seismicity, Earth Planet. Sci. Lett., 212, 279–290, 2003. Telesca, L., Cuomo, V., Lapenna, V., and Macchiato, M.: Statistical analysis of fractal properties of point processes modeling seismic sequences, Phys. Earth Planet. Int., 125, 65–83, 2001. Turcott, R. G., Lowen, S. B., Li, E., Johnson, D. H., Tsuchitani, C., and Teich, M. C.: A Nonstationary Poisson Point Process Describes the Sequence of Action Potentials Over Long Time Scales in Lateral-Superior-Olive Auditory Neurons, Biol. Cybern., 70, 209–217, 1994. Viswanathan, G. M., Peng, C.-K., Stanley, H. E., and Goldberger, A. L.: Deviations from uniform power law scaling in nonstationary time series, Phys. Rev. E, 55, 845–849, 1997.