Europhys. Lett.
Volume 71, Number 6, September 2005
Page(s) 1036 - 1042
Section Geophysics, astronomy, and astrophysics
Published online 12 August 2005
Europhys. Lett., 71 (6), pp. 1036-1042 (2005)
DOI: 10.1209/epl/i2005-10185-0

Unified scaling law for waiting times between seismic events

V. Carbone1, 2, L. Sorriso-Valvo1, 3, P. Harabaglia4 and I. Guerra1

1  Dipartimento di Fisica, Università della Calabria - Rende (CS), Italy
2  Istituto Nazionale di Fisica della Materia, Sezione di Cosenza - Rende (CS), Italy
3  Liquid Crystal Laboratory (CNR) - Rende (CS), Italy
4  Dipartimento di Strutture, Geotecnica e Geologia Applicata all'Ingegneria Università della Basilicata - Potenza, Italy

received 11 April 2005; accepted in final form 20 July 2005
published online 12 August 2005

The statistical properties of seismic time series, including both sequences of aftershocks, and patterns of occurrence of mainshocks, are studied. In this case, the universality claimed by Bak et al. (Phys. Rev. Lett. 88 (2002) 178501) about the waiting times between earthquakes, has not been found. Looking for a different law, we show that the behavior of the surviving function $P(\tau)$ of inter-event times $\tau$ satisfy a simple relation, with two free parameter, which generalizes Omori's law also to catalogues of main earthquakes. Moreover we observe that the $P(\tau)$ calculated for all catalogues we investigate, collapse to a single curve when suitably scaled. This is an indication that the above relation expresses a unified scaling law for seismic events whatever their origin. On the base of this relation it results that the seismic event occurrence pattern within a given seismogenetic area, significantly departs from a Poissonian distribution.

91.30.Dk - Seismicity: space and time distribution.
89.75.Da - Systems obeying scaling laws.
05.45.Tp - Time series analysis.

© EDP Sciences 2005