Weak signals and damage scenarios - Systematics to identify weak signals and their sources related to mass transport attacks

Mass transport systems are vital for big cities and their disruption may have severe consequences for the economy, safety and security of the general public. Thus far, the attacks on mass transport have been about twice as lethal as terrorist attacks overall. Mass transport systems are typically of open design layout with multiple access points, and these characteristics make the process of screening challenging. Therefore, the early identification of an attack plan is the most efficient way to protect such systems. This paper aims to better understand the attack phenomenon and to develop a new approach for the systematic identification of possible weak signals and their sources. If such weak signals can be timely detected and correctly interpreted, this could improve awareness and thus possibilities for intervention. The developed approach is demonstrated by applying it to two well-known but different cases: the Tokyo sarin attack of 1995 and the 2005 London bombings.