It is important to stress that hazard and risk assessment are two separate fields of expertise though being strongly connected.
While the more scientific field of seismic hazard assessment deals with the properties of the earthquake itself, i.e., the (spectral-dependent) ground motion level, the more recent field of seismic risk assessment addresses which consequences this respective seismic ground motion may cause to a particular site, the built environment (building or infrastructure assets) or humans. In this respect, seismic hazard establishes one key component of any seismic risk assessment.
The scheme below illustrates the general “qualitative risk equation”. In order to estimate the seismic risk to a certain region (in terms of expected damages and losses), three integral components have to be identified, i.e., (1) hazard providing information on the seismic ground motion level (and, in case of a probabilistic risk assessment the ground motion’s probability of occurrence), (2) the vulnerability (damageability) of buildings, infrastructure facilities and the population, (3) the exposure of these assets in terms of their inventory and spatial distribution over the respective study area.
The “risk equation” illustrating the three main components towards predicting the seismic risk of a certain geographical unit.
Over the past 20 years, NORSAR has conducted numerous research and collaboration projects in many parts of the world with the main focus on earthquake hazard assessment and risk mitigation. In the course of these, often long-term projects, all elements necessary for the generation of reliable earthquake risk models have been covered in close collaboration with professionals, academic institutions and authorities of the respective regions. Thereby, NORSAR was able to build up a unique worldwide network often serving as a facilitator between regional institutions and raising awareness among the public and authorities.