Time-scaling properties of high-casualty fires in China

摘要

High-casualty fires (HCFs) involving > 3 fatalities derived from the Fire Statistical Year Book of China and Chinese Fire Services from 2002-2010 were analyzed. The aim of this study was to investigate the time-scaling properties of HCFs. The time-scaling properties were detected by means of Fano Factor (FF), Allan Factor (AF) and detrended fluctuation analysis (DFA). The results of FF and AF show that the HCF sequences with death > 3 and death > 4 exhibit obvious time scaling behavior after the fractal onset times. The scaling exponents of FF and AF decrease significantly with increasing fatality, which reflects that HCF sequences with more fatalities tend to behave as Poisson process. The sequence of HCFs with death > 6 can be considered as a Poisson process according to the comparison of FF (AF) curve and Poissonian 95% confidence curve. The DFA scaling exponent of HCF sequence involving fatality > 3 is approximate 0.551±0.005, indicating that this sequence exhibits long-range correlations. With the increase of fatality threshold the DFA scaling exponent gradually decreases to about 0.5, which reflects that the HCFs with high fatality levels are likely to be uncorrelated. Furthermore, the sequence of HCFs with death > 6 can be regarded as uncorrelated because its DFA scaling exponent is 0.496±0.003.