Seismic Risk Definition

Seismic risk is the probability that a subject site will be adversely affected by any seismic hazard, such as an earthquake. Seismic risk tends to increase in areas that are more earthquake-prone and vulnerable to damage. And vulnerability refers to the potential impact on people, as well as properties. For instance, places that are densely populated, and have numerous buildings that are not structurally sound to withstand an intense seismic event.

While the descriptions of seismic risk hazards are relatively straightforward, a seismic risk assessment is a professional service that provides a detailed investigation and report of the matter. Seismic risk assessments are an important part of the real estate due diligence process. For these reasons, licensed professional geologists are often employed to conduct a seismic risk assessment that will meet the specific needs of the property owner or developer.

Seismic Hazard

Seismic hazard refers to the natural phenomenon of earthquakes, or earthquake-induced tsunamis, landslides, avalanches, sinkholes, and more. Thus, seismic risk is determined by the likelihood that an earthquake could negatively impact the people and property where such a hazard occurs. For example, consider two areas that are equally prone to earthquakes. And one location lies in an undeveloped area, while the other is within a densely populated and developed city. While the seismic hazard occurrence may be equal at both sites, the seismic risk is greater in the second scenario, because more people and property are vulnerable to damage.

Even more specifically, professionals can assess two different cities with equal seismic hazards and equal populations.  To illustrate, if one city comprises structures that are more structurally sound, then that city would have lower seismic risk because its buildings are less vulnerable to damage during a catastrophic event.