Thirty years of earthquake retrofit in the city of Los Angeles: Trends, drivers, and implications for seismic resilience

This study examines three decades of seismic retrofit activity in the City of Los Angeles to assess how the implementation has varied across space, time, and socially vulnerable communities. Using more than 29,000 building permits and census-tract sociodemographic data, we analyze temporal and spatial patterns for five vulnerable building types, with detailed focus on cripple-wall and soft-story woodframe structures.

The results also show statistically significant positive associations between social vulnerability and retrofit rates and benefits for cripple-wall buildings. However, the association for soft-story retrofit rates is negative and statistically significant. In general, the results underscore the progress made in reducing seismic vulnerability in the city and the need for more risk-aligned mitigation strategies.