Risk Analysis Of Dirty Bomb Terrorist Attacks In Key Urban Areas

The urban dirty bomb terrorist attack is an unconventional form of terrorism with a wide range of influence,strong concealment,high technical means,and severe consequences.At present,there are few related studies on critical urban areas with dense infrastructure and complex public environments as research areas.Besides,there is a general lack of a full-chain analysis of the dirty bomb terrorist attacks’ risk evolution process.This article aims at the prevention needs of dirty bomb terrorist attacks in key urban areas.Based on the experts’ experience and the data sources from the Global Terrorism Database and real cases,we established a Bayesian network-based dirty bomb analysis model for weapon acquisition risk and a matrix game-based model for terrorist attack target selection preference.On this basis,a multi-agent simulation model of dirty bomb terrorist attacks in key areas of the city,including the three main subjects of dirty bomb terrorist attackers,urban defence forces,and urban disaster-bearing carriers,was established to analyse the different types of terrorist attacks.Thus,the possibility of successfully launching an attack under the scenario and the effectiveness of different preventive methods were studied,such as patrol and interrogation,plainclothes investigation,and security check.The results of the study are as follows.(1)Taking the critical area of a large city in northern China as the research object,a Bayesian network model was established based on case studies and public security business experts’ experience.Here,terrorists’ approaches to acquiring radioactive materials and fabricating dirty bomb weapons were analysed.The results show that the probability of terrorist organizations successfully obtaining radioactive materials is 2.33%,and the probability of successfully preparing dirty bombs weapons is 0.29%.Through sensitivity analysis,it was found that as the main influencing factor of “terrorist organization’s acquisition of radioactive materials”(59.68%),“illegal trading channels” are far more important than “theft channels”(24.3%).(2)From the calculation results of the terrorist attack model for weapon selection preference,terrorist organizations are more inclined to choose the dirty bomb attack method,under the premise of having dirty bomb weapons(rather than the typical way of high explosive attack or firearm attack).The probability of adopting this attack method is 69～82%.According to the calculation results of the dirty bomb terrorist model for attack strategy selection preference,terrorist organizations are more inclined to choose outdoor crowded places and detonate a bomb(rather than detonating in a remote upwind direction or entering the interior of the building).The probability of using this attack strategy is 58.4～100%.(3)According to the results of the multi-agent simulation model of dirty bomb terrorist attacks in key urban areas,the probability of success of the attack is restricted by the city’s defence forces when the attacker targets outdoor crowds.In the 1140 simulation examples,the check bayonet as the city’s static defence force captured the attackers three times,and the police’s main body as the city’s dynamic defence force captured the attackers 590 times.Therefore,the police’s main body has a more significant role in compensating the risk of dirty bomb terrorist attacks.When the attacker targets the building’s insiders,increasing the spatial distance between the attackers and the target buildings can effectively reduce the attackers’ success probability and significantly improve the defence against dirty bomb for cities’ key areas.This paper’s research results are expected to provide a reference basis and method support for the formulation of risk prevention and control strategies for dirty bomb terrorist attacks in key urban areas.