Luciano Pietronero

Publications (3)2.99 Total impact

• Source

  Available from: uniroma1.it

  Article: Space–time correlation of earthquakes

  Patrizia Tosi, Valerio De Rubeis, Vittorio Loreto, Luciano Pietronero
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  ABSTRACT: Seismicity is a complex process featuring non-trivial space–time correlations in which several forms of scale invariance have been identified. A frequently used method to detect scale-invariant features is the correlation integral, which leads to the definition of a correlation dimension separately in space and time. In this paper, we generalize this method with the definition of a space–time combined correlation integral. This approach allows us to analyse medium-strong seismicity as a point process, without any distinction among main, after or background shocks. The analyses performed on the catalogue of worldwide seismicity and the corresponding reshuffled version strongly suggest that earthquakes of medium-large magnitude are time clustered inside specific space–time regions. On the basis of this feature, we recognize a space–time domain statistically characterized by sequences' behaviour and a domain of temporal randomness. Then, focusing on the spatial distribution of hypocentres, we find another domain confined to short distances and characterized by a relatively high degree of spatial correlation. This spatial domain slowly increases with time: we interpret this as the ‘afterevent’ zone representing the set of all subsequent events located very near (about 30 km) to each reference earthquake and embedded on specific seismogenic structures such as faults planes.
  Geophysical Journal International 05/2008; 173(3):932 - 941. · 2.42 Impact Factor
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  Available from: Patrizia Tosi

  Article: Space-time combined correlation integral and earthquake interactions

  Patrizia Tosi, Valerio De Rubeis, Vittorio Loreto, Luciano Pietronero
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  ABSTRACT: Scale invariant properties of seismicity argue for the presence of complex triggering mechanisms. We propose a new method, based on the space-time combined generalization of the correlation integral, that leads to a self-con-sistent visualization and analysis of both spatial and temporal correlations. The analysis was applied on global medium-high seismicity. Results show that earthquakes do interact even on long distances and are correlated in time within defined spatial ranges varying over elapsed time. On that base we redefine the aftershock concept.
  Annals of geophysics = Annali di geofisica 12/2005; 47(6):1849-1854. · 0.57 Impact Factor
• Source

  Available from: Patrizia Tosi

  Article: Influence length and space-time correlation between earthquakes

  Patrizia Tosi, Valerio De Rubeis, Vittorio Loreto, Luciano Pietronero
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  ABSTRACT: Short and long range interactions between earthquakes are attracting increasing interest. Scale invariant properties of seismicity in time, space and energy argue for the presence of complex triggering mechanisms where, like a cascade process, each event produces aftershocks. A definitive method to assess any connection between two earthquakes separated in time and distance does not exist. Here we propose a novel method of data analysis that, based on the space-time combined generalization of the correlation integral leads to a self-consistent visualization and analysis of both spatial and temporal correlations. When analyzing global seismicity we discovered a universal relation linking the spatial Influence Length of a given earthquake to the time elapsed from the event itself. Following an event, time correlations (i.e. causality effects) exist in a region that shrinks over time, suggesting a long-range dissipating stress transfer. A different process is acting in the short-range where events are randomly set, evidencing a sub-diffusive growth of the seismogenic zone.
  10/2004;