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

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