ST-RISK™ is an earthquake risk management tool that can be used for individual buildings. In helping to manage risk, the program must first be able to quantify it.
In the course of quantifying a building's risk to earthquake damage, the hazard must first be determined. The hazard reflects the probability that various levels of ground shaking will occur. A specific site's susceptibility to ground shaking is due to the following factors:
- Proximity of site to active faults
- Recurrence rate of events on nearby faults
- Size of events that can be generated on nearby faults
- Local soil conditions
The hazard only reflects to the likelihood and intensity of ground shaking. To obtain risk measurements, the effects of the ground movement on the building must also be considered. As the ground underlying a building shakes, the building suffers damage, and damage results in economic loss. Higher levels of shaking cause higher levels of damage and higher levels of loss. Risk, therefore, reflects the likelihood that certain levels of economic loss will occur.
Historical loss data, organized engineering reconnaissance information, and instrumental ground shaking measurements are used by ST-RISK™ to correlate ground movement with economic loss. This correlation has been done for different levels of ground shaking, different building types and different building characteristics.
Important characteristics essential to seismic resilience have been identified by FEMA-310. ST-RISK™ provides a FEMA-310 worksheet that enables an engineer to properly characterize structural strengths and deficiencies.