The ShakeMap and the Emilia-Lombardia 2012 Earthquake

ShakeMap is a product of the USGS Earthquake Hazard Program: the aim is to provide near real-time ground motion maps after significant earthquakes (approx. M > 5.5). The results are given in terms of PGA and spectral accelerations for 3 periods: 0.3, 1 and 3 s, which are the reference spectral periods of UBC (Uniform Building Code). This product has been adopted by INGV (Istituto Nazionale di Geofisica e Vulcanologia) to generate shake maps for Italian earthquakes immediately after a major quake. The Italian national law 122/2012, signed after the Emilia-Lombardia 2012 earthquake, is entirely devoted to the reconstruction of the damaged zones and includes several procedures to foster a quick restart of the economic activities. To assess, as soon as possible, the safety level of buildings (in particular factories) within the shaken area, the law established a criteria based on the degree of damage of the building and the ground motion at the building site. If the ground motion computed on the basis of the shake maps is greater than a given percentage of the design spectrum required by the National building code (NTC 2008) and the building did not undergo inelastic deformations, the building is granted the required safety clearance. Starting from the data provided by INGV we herein explain the procedure and the criteria that lead to the preparation of the Lombardia 2012 earthquake shake map formally adopted by the Lombardia Administration.