New vulnerabilities of historic urban centers and archaeological sites: Extreme loads

Extreme actions represent a high risk for buildings belonging to historic urban areas and archaeological sites. Because of the conformation of the buildings, the low quality of used materials and the current state of conservation, these buildings tend to be very vulnerable to horizontal forces generated during earthquakes and terrorist attacks. This article analyses the mechanisms caused by extreme actions that are capable to generate a considerable degree of damage or even collapse of international cultural heritage buildings from historic urban centers and sites.