A California Earthquake Authority Proxy Portfolio

This comma-separated-value file provides an estimate of the insured building stock of single-family dwellings in California as of 2019. We created it to inform a risk analysis described in Porter et al. (in press 2024). It depicts the building stock in terms of its replacement cost in 2019 US dollars. It shows those values subtotalled by census tract, model building type, and code era. "Model building type" refers to the US Federal Emergency Management Agency's (FEMA) FEMA P-154 and Hazus categories. For example W1 refers to small woodframe construction and RM1 refers to reinforced masonry with flexible diaphrams. "Code era" refers to (generally three) degrees of earthquake-resistance requirements--pre-code, moderate code, and high code--embedded in building codes and reflected in the seismic strength of buildings of their day. The file was built from data tables in Hazus that encode a 2010-era estimate of the building stock. We increased the quantity of buildings in that 2003 estimate by scaling for state population growth and inflation from 2010 to 2019. We filtered that Hazus-based data to include only single-family dwellings, referred to as "RES1" occupancy. We then scaled values down in proportion to the fraction of existing homes insured by the California Earthquake Authority. Thus, the resulting data set approximates the portfolio of buildings insured by the California Earthquake Authority. Why filter just for RES1 and scale for the California Earthquake Authority's market penetration? Two pragmatic reasons. First, filtering for RES1 buildings greatly reduced the (very demanding) computational effort required for Porter et al. (expected 2024). Second, the risk analysis was funded by the California Earthquake Authority.

Porter, K., Milner, K., and Field, E. (in press 2024). Trimming the UCERF3-TD logic tree: model order reduction for an earthquake rupture forecast considering loss exceedance. Earthquake Spectra, accepted September 2023.