Advanced intensity measures for urban seismic-risk mapping: Evidence from a Megacity

A series of spatial analyses were conducted to examine the correlation between seismic intensity—using both traditional and advanced intensity measures—and the structural damage observed in buildings affected by the 2017 Puebla earthquake in Mexico City. Probabilistic seismic hazard analyses were performed to generate seismic intensity maps based on PGA and Sa(T₁) and the advanced intensity measure I_Np, which incorporates period elongation due to nonlinear structural behavior. A recently released government database of damaged low- and mid-rise buildings was used in the analyses. Moran's Index and Local Indicators of Spatial Association revealed significant spatial autocorrelation between seismic demand and damage distribution. To evaluate which measure better reflects the observed damage, overlay and proximity analyses were applied. Results show that while both intensity measures perform similarly for short-period structures, I_Np outperforms Sa(T₁) for mid-rise buildings; particularly at intermediate-to-long vibration periods. These findings support the integration of I_Np into seismic risk mapping and mitigation strategies for urban environments.