European Cities Prone to Terrorist Threats: Phenomenological Analysis of Historical Events towards Risk Matrices and an Early Parameterization of Urban Built Environment Outdoor Areas

Abstract

Among other risks, contemporary cities are exposed to terrorism. In addition to being sensitive targets, recent events in Europe have underlined the relevance of public open spaces (squares, streets, etc.) as particularly defenseless parts of Urban Built Environments (UBEs). Despite the fact that previous theoretical studies about radicalism have highlighted the “regional” dimension of the threat, the assessment of terroristic risk is still related to American guidelines. This creates new research scenarios for European UBEs and associated Outdoor Areas (UBEOAs). Thus, this paper provides two correlated main goals. The first is the phenomenological analysis of terrorist threats in European UBEs, starting from the events catalogued in the Global Terrorism Database. Specifically, the matrix of risk is assessed by combining (i) the main urban Environmental Classes (ECs) and their sub-classes, referred to as Outdoor Areas (OutECs), and (ii) the Attack Types (ATs) in order to determine the most efficient and recurrent combination of attack methods and targets (AT-EC and AT-OutEC). Then, the paper identifies the parameters influencing the terroristic risk of the most recurrent and efficient attacks identified in European UBEOAs, starting from (i) the analysis of inherent features of the European phenomenon, (ii) previous experiences in the literature and (iii) the permitted strategies and guidelines in European States. The main results are related to the relevance of Armed Assault and Bombing/Explosion Ats and Open Areas with the presence of public and strategic/symbolic buildings (ECs), while an interesting point of discussion is represented by physical obstacles.

How Could Increasing Temperature Scenarios Alter the Risk of Terrorist Acts in Different Historical Squares? A Simulation-Based Approach in Typological Italian Squares

“…The BE S 2 ECURe project aims at developing methods for risk assessment and mitigation in crowded open spaces, focusing on historical squares, and evaluating the combined impact of built environment features, other boundary conditions related to climate change and anthropogenic hazards (i.e., increasing temperatures and pollution), emergency conditions implying evacuation (i.e., terrorist acts and earthquakes) and users' behaviours. Previous works were devoted to (a) the identification of typological scenarios of risk-prone built environments based on the analysis of real-world squares [48], (b) the simulation-based analysis of their outdoor conditions in the case of increasing temperatures [30,59], and (c) the identification of the main terrorist risk factors in squares [7,19]. This contribution moves towards the next required step concerning the analysis of the joint effects of these elements on the users' risk during the evacuation process and hence traces the methodological bases for specific case study applications.…”

“…According to Section 2.1, the presence of a special building implies that the BET is prone to terrorist acts in view of its symbolic value and its potentially high number of hosted users [7,16,17]. According to the work aims, two kinds of evacuation scenarios are simulated in this work, and both of them imply the evacuation of the outdoor spaces of the square.…”

“…Historical squares are public open spaces in the urban built environment and fundamental parts of the urban tangible cultural heritage [1,2]. They are significant attractors of users to our historical cities, given their social and cultural functions [3][4][5], thus being affected by high potential risk levels in case of an emergency [6][7][8][9] due to a natural or anthropogenic disaster [10].…”

“…In particular, squares can be identified as potential "soft targets" prone to terrorist acts [7,[16][17][18][19]. They can be classified as public open spaces with "low or no security against violent attacks and attraction for the attacker" due to the aforementioned high exposure [16].…”

Mapping the Multi-Vulnerabilities of Outdoor Places to Enhance the Resilience of Historic Urban Districts: The Case of the Apulian Region Exposed to Slow and Rapid-Onset Disasters

“…As the last ROD event to discuss, the terrorist threat and its overall mechanism in risk assessment were not extensively discussed in scientific fields, particularly in Europe. The last studies that referred to such events are discussed [37,38]. Here, the parameters of the built environment are examined to describe and classify the most used mitigation strategies.…”