Earthquakes Risk is not based on climate projections, but on a static geographical analysis assessing seismic threat. To calculate Seismic Risk, we use a single key indicator from earthquake engineering:
The methodology described for Seismic Risk assessment is fully in line with fundamental principles of earthquake engineering and Seismic Hazard Assessment. It is based on a standard indicator (PGA), uses a historical and reference global data source (GSHAP), and correlates shaking levels to expected damage in a scientifically consolidated way.
Peak Ground Acceleration (PGA) is the most common and fundamental parameter used in technical codes (like Eurocode 8 EN 1998 in Europe or FEMA in the United States) for construction worldwide to define design seismic action.
These codes, which are legally binding for new building design, define seismic forces a structure must be able to withstand precisely in PGA terms. For example, Eurocode 8 maps national territory into seismic zones, each assigned a reference PGA value for design. This confirms that PGA is the standard indicator used by engineering to quantify potential earthquake damage.Our risk scale links specific PGA values to damage descriptions. This relationship has been studied and scientifically formalized, particularly to correlate instrumental measures (PGA) with macroseismic intensity scales (like Modified Mercalli Scale - MMI), which are based on observed effects.
The methodology described for Seismic Risk assessment is fully in line with fundamental principles of earthquake engineering and Seismic Hazard Assessment. It is based on a standard indicator (PGA), uses a historical and reference global data source (GSHAP), and correlates shaking levels to expected damage in a scientifically consolidated way.
• [The GSHAP Global Seismic Hazard Map](The GSHAP Global Seismic Hazard Map)
The Global Seismic Hazard Assessment Program (GSHAP), concluded in 1999, was a pioneering United Nations project that produced the first globally homogeneous seismic hazard map. The map shows Peak Ground Acceleration (PGA) values with a 10% probability of exceedance in 50 years (equivalent to a 475-year return period), which is a standard parameter for seismic design. Although dated, it remains a fundamental and reference source.
Peak Ground Acceleration (PGA) is the most common and fundamental parameter used in technical codes (like Eurocode 8 EN 1998 in Europe or FEMA in the United States) for construction worldwide to define design seismic action.
These codes, which are legally binding for new building design, define seismic forces a structure must be able to withstand precisely in PGA terms. For example, Eurocode 8 maps national territory into seismic zones, each assigned a reference PGA value for design. This confirms that PGA is the standard indicator used by engineering to quantify potential earthquake damage.Our risk scale links specific PGA values to damage descriptions. This relationship has been studied and scientifically formalized, particularly to correlate instrumental measures (PGA) with macroseismic intensity scales (like Modified Mercalli Scale - MMI), which are based on observed effects.
• [Relationships between peak ground acceleration, peak ground velocity, and Modified Mercalli Intensity in California](Relationships between peak ground acceleration, peak ground velocity, and Modified Mercalli Intensity in California)
The equations defined in this article are the reference standard for 'translating' a measured PGA value into an MMI intensity level and, therefore, into an expected damage description. Our classification reflects these correlations: