The seismic risk assesses the site's earthquake hazard. It does not depend on the climate scenarios: it is a static property of the territory. It is measured with the Peak Ground Acceleration (PGA), the maximum expected ground acceleration during an earthquake, the main parameter for estimating shaking and potential structural damage.
Indicator. Peak Ground Acceleration (PGA), in m/s².
Data. GSHAP global seismic hazard map (Global Seismic Hazard Assessment Program); the PGA represents a 10% probability of exceedance in 50 years (return period 475 years). Static value, independent of the scenario (same value for all SSP scenarios and years).
Calculation. The GSHAP PGA is read for the site's location and absolute acceleration thresholds are applied to assign the level; the value is replicated identically across all scenarios and years.
Thresholds → level A–F.
• Based on the PGA (m/s²): A: up to 0.49 (0.05 g)
• B: above 0.49 up to 0.98 (0.1 g)
• C: above 0.98 up to 1.96 (0.2 g)
• D: above 1.96 up to 3.92 (0.4 g)
• E: above 3.92 up to 7.85 (0.8 g)
• F: above 7.85.
A PGA exactly equal to a threshold falls in the lower class. The 0.05 / 0.1 / 0.2 / 0.4 / 0.8 g thresholds are a xNatura choice without a published source.
From physical to impact. The physical level (A–F) is combined with the production process's sensitivity through the risk matrix (6 physical levels by 5 sensitivity bands) → impact level. The euro amount of this risk is the one described in the "Economic damage" paragraph (Version 2026): the damage factor per class of Version 2025 is no longer used for this risk.
Economic damage. Besides the class, the loss in euro is estimated as a share of the asset value (book value of building and contents).
• In Europe (the 44 countries of the European Seismic Risk Model ESRM20): the mix of industrial or commercial building classes of the area (ESRM20 exposure of the nearest point; if the site has its structure type, only the classes of that material) and, for each class, the ESRM20 vulnerability curve, i.e. the share of value lost at each shaking intensity. Combined with the ESHM20 hazard curve on rock it gives the expected annual loss and the loss at the shaking that comes back once in 100 years. Basis: published source.
• Outside Europe (for now also in the USA): the loss at the 475-year shaking of the GSHAP map, with the FEMA Hazus damage curves of the site's structure type, calibrated on United States buildings. The seismic design level comes from the year of construction with the Hazus rule (UBC 1997 seismic zone derived from the PGA, and US code years); without a year the lowest level is used. Without a structure type the mean of the seven types is used: basis "xNatura estimate".
Simplifications: shaking on rock (ESHM20 and GSHAP do not give the soil), replacement cost equal to the book value, one building type per site.
Sources.
• [The GSHAP Global Seismic Hazard Map](The GSHAP Global Seismic Hazard Map)
• [European Seismic Risk Model 2020 (ESRM20)](European Seismic Risk Model 2020 (ESRM20))
• [European Seismic Hazard Model 2020 (ESHM20)](European Seismic Hazard Model 2020 (ESHM20))
• [FEMA Hazus Earthquake Model Technical Manual 6.1](FEMA Hazus Earthquake Model Technical Manual 6.1)
• [FEMA Hazus Inventory Technical Manual 6.1](FEMA Hazus Inventory Technical Manual 6.1).
Indicator. Peak Ground Acceleration (PGA), in m/s².
Data. GSHAP global seismic hazard map (Global Seismic Hazard Assessment Program); the PGA represents a 10% probability of exceedance in 50 years (return period 475 years). Static value, independent of the scenario (same value for all SSP scenarios and years).
Calculation. The GSHAP PGA is read for the site's location and absolute acceleration thresholds are applied to assign the level; the value is replicated identically across all scenarios and years.
Thresholds → level A–F.
• Based on the PGA (m/s²): A: up to 0.49 (0.05 g)
• B: above 0.49 up to 0.98 (0.1 g)
• C: above 0.98 up to 1.96 (0.2 g)
• D: above 1.96 up to 3.92 (0.4 g)
• E: above 3.92 up to 7.85 (0.8 g)
• F: above 7.85.
A PGA exactly equal to a threshold falls in the lower class. The 0.05 / 0.1 / 0.2 / 0.4 / 0.8 g thresholds are a xNatura choice without a published source.
From physical to impact. The physical level (A–F) is combined with the production process's sensitivity through the risk matrix (6 physical levels by 5 sensitivity bands) → impact level. The euro amount of this risk is the one described in the "Economic damage" paragraph (Version 2026): the damage factor per class of Version 2025 is no longer used for this risk.
Economic damage. Besides the class, the loss in euro is estimated as a share of the asset value (book value of building and contents).
• In Europe (the 44 countries of the European Seismic Risk Model ESRM20): the mix of industrial or commercial building classes of the area (ESRM20 exposure of the nearest point; if the site has its structure type, only the classes of that material) and, for each class, the ESRM20 vulnerability curve, i.e. the share of value lost at each shaking intensity. Combined with the ESHM20 hazard curve on rock it gives the expected annual loss and the loss at the shaking that comes back once in 100 years. Basis: published source.
• Outside Europe (for now also in the USA): the loss at the 475-year shaking of the GSHAP map, with the FEMA Hazus damage curves of the site's structure type, calibrated on United States buildings. The seismic design level comes from the year of construction with the Hazus rule (UBC 1997 seismic zone derived from the PGA, and US code years); without a year the lowest level is used. Without a structure type the mean of the seven types is used: basis "xNatura estimate".
Simplifications: shaking on rock (ESHM20 and GSHAP do not give the soil), replacement cost equal to the book value, one building type per site.
Sources.
• [The GSHAP Global Seismic Hazard Map](The GSHAP Global Seismic Hazard Map)
• [European Seismic Risk Model 2020 (ESRM20)](European Seismic Risk Model 2020 (ESRM20))
• [European Seismic Hazard Model 2020 (ESHM20)](European Seismic Hazard Model 2020 (ESHM20))
• [FEMA Hazus Earthquake Model Technical Manual 6.1](FEMA Hazus Earthquake Model Technical Manual 6.1)
• [FEMA Hazus Inventory Technical Manual 6.1](FEMA Hazus Inventory Technical Manual 6.1).