Search

The temporal fluctuations of the 1880–1994 seismicity recorded in Pannonian Basin were investigated by means of the Fano Factor and Allan Factor methods, which allows us to estimate the power spectrum for point processes. Up to our knowledge, this is the first scaling analysis performed on earthquake series spanning for almost one century. Our findings point out a presence of two temporal regimes in the analyzed seismicity, which is characterized by quasi-Poissonian behavior for low to intermediate timescales for up to about 1/2 years, and by scaling behavior for higher timescales with scaling exponent around 0.3–0.4, indicating a rather high time-clustering of the events. Furthermore the Allan Factor shows the presence of a periodicity at about 2.23 years for events with magnitude larger or equal to 3.5. [ABSTRACT FROM AUTHOR]

Lightning data, measured from April to October 2002 in an area of northern Italy, have been analyzed by using the Allan Factor statistics. The sequence of lightning time-occurrences is characterized by two scaling regions, which reveal intra-cluster (inside an individual thunderstorm) and inter-cluster (among successive thunderstorms) time-clustering properties of lightning data. We investigated intra- and inter-cluster correlations for three classes of lightning: (i) the whole series, (ii) the sequence of only negative flashes and (iii) that of only positive flashes. Furthermore, we performed the analysis of the scaling behavior of the three classes of lightning varying the current intensity threshold. [ABSTRACT FROM AUTHOR]

The time-clustering behavior of the neutron star SGR1806-20 burst sequence (detected by the International Cometary Explorer, ICE) has been analyzed. The presence of two different timescaling regions, related to the "foreshock" and "aftershock" phases, separated by the largest event occurred on November 16, 1983, 8:34 GMT, E = 5.17 · 1041erg, has been evidenced. The results highlight that starquake foreshocks involve medium timescales from about 30 minutes to approximately 5 days, while starquake aftershocks involve longer timescales ranging up 4 months. [ABSTRACT FROM AUTHOR]

Point processes, like other geophysical phenomena, such as earthquakes or avalanches, are well suited to model rain event sequences. Time-clustering analysis has been performed over rainfall sequences by using the statistical approaches of Fano Factor and Allan Factor. The obtained results suggest the presence of clustering in the time distribution of the sequence of rain events, with scaling exponent α ranging between ~0.35 and ~0.42. [ABSTRACT FROM AUTHOR]

Time regimes in fire data recorded from 1992 to 2007 in a fire vulnerable area of Patagonia (Argentina) were revealed by using the Allan Factor statistics. The obtained results show the presence of seasonal periodicities, superimposed to three time-scaling regimes, which characterize the point process of the fire sequence as a fractal time process with a rather high degree of time-clusterization of the events. [ABSTRACT FROM AUTHOR]

Two years of lightning data, measured during 2002 and 2003 in an area of southern Italy, have been analyzed in order to reveal scaling behaviour in their time dynamics. We used the Allan Factor method to evidence the presence of time-clustering in the lightning data. We found that i) the sequence of lightning time-occurrences is characterized by two scaling regions, which reveal intra-cluster (inside an individual thunderstorm) and inter-cluster (among successive thunderstorms) time-clustering properties of lightning data. A crossover timescale is identified, which is connected with the mean duration of a thunderstorm. We investigated intra- and inter-cluster time-dynamics for the whole sequence as well as the sequence of only positive and only negative flashes. The negative lightning show a time-clustering feature stronger than that of the positive lightning. [ABSTRACT FROM AUTHOR]