Hazard and risk modelling
While earthquakes cannot yet be prevented or reliably predicted, research has significantly improved our ability to assess earthquake hazard and risk.
Earthquake hazard describes how strong the ground shaking could be at a specific place and how often such shaking may occur. It depends on where earthquakes can happen, how large they can be, how seismic waves travel through the ground, and how local soil or rock conditions can increase or reduce shaking.
Earthquake risk describes what this shaking could mean for people and society. It looks at the possible damage to buildings and infrastructure, the financial losses that may result, and the potential effects on people’s safety and daily life. Risk therefore depends not only on the earthquake itself, but also on where people live, how buildings are constructed, and how well communities are prepared.
From hazard modelling to risk assessment
For decades, research has focused primarily on earthquake hazard modelling. However, as populations grow and the built environment expands, there is an increasing need to understand the broader effects of earthquakes. Advances in data collection, computational modelling, exposure information, and vulnerability assessment now make it possible to estimate not only where and how strongly the ground may shake, but also what this shaking may mean for buildings, infrastructure, people, and society. This risk perspective supports mitigation planning, preparedness, emergency response, and long-term risk reduction.
Hazard and risk models can be developed at different spatial scales, depending on the purpose of the assessment and the decisions they are intended to support. They may focus on individual sites or critical facilities, cities and cantons, national territories, larger regions such as Europe, or the global scale.
At local and site-specific scales, models can support detailed engineering studies and infrastructure planning. At national and regional scales, they provide input for building codes, risk reduction strategies, insurance applications, and civil protection planning. Global models are used to compare earthquake hazard and risk across countries and to support international disaster risk reduction efforts.
How earthquake hazard and risk models are used
Earthquake hazard and risk models provide a scientific basis for decisions in engineering, spatial planning, insurance, civil protection, and public policy. Engineers and urban planners use hazard information to design safer buildings and infrastructure. Public authorities use hazard and risk estimates to develop building regulations, preparedness plans, and risk reduction strategies. Civil protection agencies and first responders use earthquake scenarios and impact assessments to support emergency planning and response.
Hazard models are used to define seismic design requirements by estimating the levels of ground shaking that buildings and infrastructure should be able to withstand. Risk models go one step further by estimating the possible consequences of this shaking. They can be used to assess damage and losses for building portfolios, support insurance and reinsurance applications, compare the benefits of preventive measures, and provide input for emergency response strategies.
Furthermore, risk models support the development of products for disaster risk management and preparedness, such as scenarios and rapid impact assessments.
Earthquake hazard and risk modelling at SED
The SED designs and implements seismic hazard and risk models at various scales, from site-specific to national and regional. This compromises the implementation of all components and models including the handling of the computational aspects.