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Rapisarda, A.
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Rapisarda, A.
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5 results
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- PublicationRestrictedDetection of invisible and crucial events: from seismic fluctuations to the war against terrorism(2004)
; ; ; ; ; ; ; ; ;Allegrini, P.; Istituto di Linguistica Computazionale del Consiglio Nazionale delle Ricerche, Area della Ricerca di Pisa ;Fronzoni, L.; Dipartimento di Fisica dell’Università di Pisa and NFM e Centro Interdipartimentale per lo Studio dei Sistemi Complessi ;Grigolini, P.; Dipartimento di Fisica dell’Università di Pisa and NFM e Center for Nonlinear Science, University of North Texas e Istituto dei Processi Chimico Fisici del CNR Area della Ricerca di Pisa ;Latora, V.; Università di Catania, Dipartimento di Fisica e Astronomia ;Mega, M. S.; Università di Pisa and NFM, Dipartimento di Fisica ;Palatella, L.; Università di Pisa and NFM, Dipartimento di Fisica ;Rapisarda, A.; Università di Catania, Dipartimento di Fisica e Astronomia ;Vinciguerra, S.; Università di Catania, Dipartimento di Fisica e Astronomia e Istituto di Geofisica e Vulcanologia, Osservatorio Vesuviano; ; ; ; ; ; ; We argue that the recent discovery of the non-Poissonian statistics of the seismic main-shocks is a special case of a more general approach to the detection of the distribution of the time increments between one crucial but invisible event and the next. We make the conjecture that the proposed approach can be applied to the analysis of terrorist network with significant benefits for the Intelligence Community.136 152 - PublicationRestrictedNon poisson distribution of the time distances between two consecutive clusters of earthquakes(2004)
; ; ; ; ; ; ; ;Palatella, L.; Dip. Fisica, Univ. di Pisa ;Allegrini, P.; CNR, Pisa ;Grigolini, P.; CNR, Pisa ;Latora, V.; Dip. di Fis, Univ. di Catania ;Mega, M.; Dip. Fis. , Univ. di Pisa ;Rapisarda, A.; Dip. di Fis, Univ. di Catania ;Vinciguerra, S.; Dipartimento di Fisica e Astronomia, Universit a di Catania, and INFN; ; ; ; ; ; With the help of the di0usion entropy technique we show the non-Poisson statistics of the distances between consecutive Omori’s swarms of earthquakes. We give an analytical proof ofthe numerical results of an earlier paper (Phys. Rev. Lett. 90 (2003) 188501).130 15 - PublicationRestrictedMultifractal analysis of Mt. St. Helens seismicity as a tool for identifying eruptive activity(2006)
; ; ; ; ; ;Caruso, F.; Scuola Superiore di Catania, Universit`a di Catania ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Latora, V.; Dipartimento di Fisica e Astronomia, Universit`a di Catania ;Rapisarda, A.; Dipartimento di Fisica e Astronomia, Universit`a di Catania ;Malone, S.; Department of Earth and Space Sciences, University of Washington; ; ; ; We present a multifractal analysis of Mount St. Helens seismic activity during 1980–2002. The seismic time distribution is studied in relation to the eruptive activity, mainly marked by the 1980 major explosive eruptions and by the 1980–1986 dome building eruptions. The spectrum of the generalized fractal dimensions, i.e. Dq versus q, extracted from the data, allows us to identify two main earthquake time distribution patterns. The first one exhibits a multifractal clustering correlated to the intense seismic swarms of the dome building activity. The second one is characterized by an almost constant value of Dq ≈ 1, as for a random uniform distribution. The time evolution of Dq (for q = 0.2), calculated on a fixed number of events window and at different depths, shows that the brittle mechanical response of the shallow layers to rapid magma intrusions, during the eruptive periods, is revealed by sharp changes, acting at a short time scale (order of days), and by the lowest values of Dq (≈ 0.3). Conversely, for deeper earthquakes, characterized by intense seismic swarms, Dq do not show obvious changes during the whole analyzed period, suggesting that the earthquakes, related to the deep magma supply system, are characterized by a minor degree of clustering, which is independent of the eruptive activity.141 25 - PublicationRestrictedNon-Poisson distribution of the time distances between two consecutive clusters of earthquakes(2004)
; ; ; ; ; ; ; ;Palatella, L.; INFM - Dipartimento di Fisica dell’Università di Pisa ;Allegrini, P.; Istituto di Linguistica Computazionale del CNR ;Grigolini, P.; INFM - Dipartimento di Fisica dell’Università di Pisa e Istituto dei Processi Chimico Fisici del CNR e University of North Texas, Center for Nonlinear Science ;Latora, V.; Istituto dei Processi Chimico Fisici del CNR ;Mega, M. S.; INFM - Dipartimento di Fisica dell’Università di Pisa ;Rapisarda, A.; Istituto dei Processi Chimico Fisici del CNR ;Vinciguerra, S.; Istituto dei Processi Chimico Fisici del CNR; ; ; ; ; ; With the help of the di0usion entropy technique we show the non-Poisson statistics of the distances between consecutive Omori’s swarms of earthquakes. We give an analytical proof of the numerical results of an earlier paper131 179 - PublicationRestrictedAnalysis of self-organised criticality in the Olami-Feder-Christensen model and in real earthquakes(2007-05-14)
; ; ; ; ; ;Caruso, F.; CNR-INFM and Scuola Normale Superiore, Pisa, Italy ;Pluchino, A.; Univ. of Catania, Italy ;Latora, V.; Univ. of Catania, Italy ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rapisarda, A.; Univ. of Catania, Italy; ; ; ; We perform an analysis on the dissipative Olami-Feder-Christensen model on a small world topology considering avalanche size differences. We show that when criticality appears, the probability density functions (PDFs) for the avalanche size differences at different times have fat tails with a q-Gaussian shape. This behavior does not depend on the time interval adopted and is found also when considering energy differences between real earthquakes. Such a result can be analytically understood if the sizes (released energies) of the avalanches (earthquakes) have no correlations. Our findings support the hypothesis that a self-organized criticality mechanism with long-range interactions is at the origin of seismic events and indicate that it is not possible to predict the magnitude of the next earthquake knowing those of the previous ones.141 20