INVESTIGATING CLUSTERING STRUCTURES IN TIME-OCCURRENCE SEQUENCES OF SEISMIC EVENTS OBSERVED IN THE IRPINIA-BASILICATA REGION (SOUTHERN ITALY)

Fractals ◽  
1999 ◽  
Vol 07 (03) ◽  
pp. 221-234 ◽  
Author(s):  
L. TELESCA ◽  
V. CUOMO ◽  
M. LANFREDI ◽  
V. LAPENNA ◽  
M. MACCHIATO
Keyword(s):  
Southern Italy ◽  
Temporal Distribution ◽  
Fano Factor ◽  
Seismic Events ◽  
Scale Invariant ◽  
Basilicata Region ◽  
Allan Factor ◽  
Factor Data ◽  
Occurrence Times ◽  
Scaling Coefficient

We reveal the existence of clustering properties in the temporal distribution of the earthquakes observed in a seismic active area of Southern Apennine Chain (Italy) by means of quantitatively fractal tools (Fano Factor and Allan Factor). Data consist in a sequence of seismic events instrumentally recorded during the period 1983–1995 in the Irpinia-Basilicata Region (Southern Italy), in which in past and recent years, many destructive events occurred. The analysis of the Fano and Allan Factors shows that the sequence of the occurrence times of events with magnitude M th ≥2.5 is characterized by a scale-invariant behavior from the time scale τ ~ 5 · 103 s with a scaling coefficient α ~ 0.3. By gradually increasing the threshold magnitude up to M th =3.1, the value of the scaling coefficient monotonically decreases, pointing out a falling-off in the correlation strength. Although the increasing of the threshold magnitude seems to act as a randomizing filter which removes clustered structures, no firm sign of Poissonian, memoryless behavior is detectable in our analysis.

scholarly journals Fractal properties of human muscle sympathetic nerve activity

2004 ◽  
Vol 286 (3) ◽  
pp. H1076-H1087 ◽  
Author(s):  
Paul J. Fadel ◽  
Hakan S. Orer ◽  
Susan M. Barman ◽  
Wanpen Vongpatanasin ◽  
Ronald G. Victor ◽  
...  
Keyword(s):  
Time Scale ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Fano Factor ◽  
Scale Invariant ◽  
Nerve Activity ◽  
Dispersional Analysis ◽  
Allan Factor ◽  
Burst Amplitude

Muscle sympathetic nerve activity (MSNA) in resting humans is characterized by cardiac-related bursts of variable amplitude that occur sporadically or in clusters. The present study was designed to characterize the fluctuations in the number of MSNA bursts, interburst interval, and burst amplitude recorded from the peroneal nerve of 15 awake, healthy human subjects. For this purpose, we used the Allan and Fano factor analysis and dispersional analysis to test whether the fluctuations were time-scale invariant (i.e., fractal) or random in occurrence. Specifically, we measured the slopes of the power laws in the Allan factor, Fano factor, and dispersional analysis curves. In addition, the Hurst exponent was calculated from the slope of the power law in the Allan factor curve. Whether the original time series contained fractal fluctuations was decided on the basis of a comparison of the values of these parameters with those for surrogate data blocks. The results can be summarized as follows. Fluctuations in the number of MSNA bursts and interburst interval were fractal in each of the subjects, and fluctuations in burst amplitude were fractal in four of the subjects. We also found that fluctuations in the number of heartbeats and heart period (R-R interval) were fractal in each of the subjects. These results demonstrate for the first time that apparently random fluctuations in human MSNA are, in fact, dictated by a time-scale-invariant process that imparts “long-term memory” to the sequence of cardiac-related bursts. Whether sympathetic outflow to the heart also is fractal and contributes to the fractal component of heart rate variability remains an open question.

scholarly journals Time-clustering behavior in the sequence of the aftershocks of the Al-Hoceima (Morocco) 24 February 2004 earthquake

2009 ◽  
Vol 9 (6) ◽  
pp. 2063-2066 ◽  
Author(s):  
L. Telesca ◽  
M. Rouai ◽  
T. E. Cherkaoui
Keyword(s):  
Point Processes ◽  
Fano Factor ◽  
Aftershock Sequence ◽  
Scaling Exponent ◽  
Time Dynamics ◽  
Allan Factor ◽  
Al Hoceima ◽  
Scaling Features ◽  
Clustering Behavior ◽  
Occurrence Times

Abstract. The time dynamics of the aftershock sequence of the Al-Hoceima (Morocco) earthquake of 24 February 2004 has been investigated. The sequence of the occurrence times of the events with threshold magnitude Mth≥3.2 is characterized by a time-clustering behavior, identified using different fractal methods (Fano Factor, Allan Factor, Count-based Periodogram), well suited to reveal scaling features in point processes. The obtained results not only show the presence of memory phenomena and correlation structures in the Al-Hoceima aftershocks, but also furnish quantitatively the estimate of the magnitude of such correlation by means of the estimate of the scaling exponent α.

Fractal fluctuations in human respiration

2004 ◽  
Vol 97 (6) ◽  
pp. 2056-2064 ◽  
Author(s):  
Paul J. Fadel ◽  
Susan M. Barman ◽  
Shaun W. Phillips ◽  
Gerard L. Gebber
Keyword(s):  
Time Scale ◽  
Power Laws ◽  
Fano Factor ◽  
Respiratory Pattern ◽  
Scale Invariant ◽  
Long Range Correlations ◽  
Dispersional Analysis ◽  
Human Respiration ◽  
Allan Factor ◽  
Fractal Fluctuations

The present study was designed to characterize respiratory fluctuations in awake, healthy adult humans under resting conditions. For this purpose, we recorded respiratory movements with a strain-gauge pneumograph in 20 subjects. We then used Allan factor, Fano factor, and dispersional analysis to test whether the fluctuations in the number of breaths, respiratory period, and breath amplitude were fractal (i.e., time-scale-invariant) or random in occurrence. Specifically, we measured the slopes of the power laws in the Allan factor, Fano factor, and dispersional analysis curves for original time series and compared these with the slopes of the curves for surrogates (randomized data sets). In addition, the Hurst exponent was calculated from the slope of the power law in the Allan factor curve to determine whether the long-range correlations among the fluctuations in breath number were positively or negatively correlated. The results can be summarized as follows. Fluctuations in all three parameters were fractal in nine subjects. There were four subjects in whom only the fluctuations in number of breaths and breath amplitude were fractal, three subjects in whom only the fluctuations in number of breaths were fractal, and two subjects in whom only fluctuations in breath number and respiratory period were fractal. Time-scale-invariant behavior was absent in the two remaining subjects. The results indicate that, in most cases, apparently random fluctuations in respiratory pattern are, in fact, correlated over more than one time scale. Moreover, the data suggest that fractal fluctuations in breath number, respiratory period, and breath amplitude are controlled by separate processes.

A multidisciplinary approach for landslide residual risk assessment: the Pomarico landslide (Basilicata Region, Southern Italy) case study

Landslides ◽  
2020 ◽  
Author(s):  
Angela Perrone ◽  
Filomena Canora ◽  
Giuseppe Calamita ◽  
Jessica Bellanova ◽  
Vincenzo Serlenga ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Multidisciplinary Approach ◽  
Southern Italy ◽  
Residual Risk ◽  
Basilicata Region

Geotourism as a Specialization in the Territorial Context of the Basilicata Region (Southern Italy)

Geoheritage ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 1435-1445 ◽  
Author(s):  
A. Pilogallo ◽  
G. Nolè ◽  
F. Amato ◽  
L. Saganeiti ◽  
M. Bentivenga ◽  
...  
Keyword(s):  
Southern Italy ◽  
Basilicata Region

1/fα FLUCTUATIONS OF SEISMIC SEQUENCES

2002 ◽  
Vol 02 (04) ◽  
pp. L357-L367 ◽  
Author(s):  
LUCIANO TELESCA ◽  
VINCENZO CUOMO ◽  
VINCENZO LAPENNA ◽  
MARIA MACCHIATO
Keyword(s):  
Power Law ◽  
Point Processes ◽  
Fano Factor ◽  
Temporal Fluctuations ◽  
Time Dynamics ◽  
Seismic Sequences ◽  
Seismic Zones ◽  
Allan Factor ◽  
Correlation Properties

We investigate the time dynamics of sequences of earthquakes occurred in three different seismic zones in Italy. All the series analyzed present 1/f α temporal fluctuations, shown by the power-law behaviour of several statistics (Fano Factor, Allan Factor and Count-based Periodogram), that allow to detect correlation properties in point processes.

EVIDENCE FOR A FRACTAL STOCHASTIC PROCESS UNDERLYING MEASLES EPIDEMICS IN BRITAIN

Fractals ◽  
2000 ◽  
Vol 08 (01) ◽  
pp. 29-34 ◽  
Author(s):  
WAYNE S. KENDAL
Keyword(s):  
Stochastic Process ◽  
Time Series ◽  
Spectral Density ◽  
Geometric Distribution ◽  
Fano Factor ◽  
Distribution Histogram ◽  
Power Spectral ◽  
Allan Factor ◽  
Measles Incidence ◽  
Vaccination Period

The variability in measles incidence during the pre-vaccination period of 1944 to 1966, as recorded from 366 communities in England and Wales, was examined for properties of fractal stochastic processes. The power spectral density, Fano factor, and Allan factor were computed from the incidence time-series, and all revealed power-law scaling. As well, the distribution histogram for the weekly incidence approximated a geometric distribution. These features constituted evidence for a fractal stochastic process with underlying geometric statistics at play in the development and resolution of measles epidemics.

IDENTIFYING TIME-CLUSTERING STRUCTURES IN LIGHTNING SEQUENCES

2005 ◽  
Vol 05 (04) ◽  
pp. L507-L514 ◽  
Author(s):  
LUCIANO TELESCA ◽  
MARINA BERNARDI ◽  
CINZIA ROVELLI
Keyword(s):  
Southern Italy ◽  
Time Dynamics ◽  
Factor Method ◽  
Scaling Behaviour ◽  
Allan Factor ◽  
The Mean

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.

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