Are people equally exposed to seismic and climate-change-induced hazards? Evidence from the San Francisco Bay Area

Many studies have shown that a comprehensive plan with sufficient mitigation elements can significantly reduce natural disaster impact. However, they often neglect the need to match the implementation of mitigation measures to the local conditions because the ability to cope with impacts from a severe disaster varies by socioeconomic group. Therefore, it is extremely important to identify who and what are more exposed to a natural hazard and design adequate mitigation measures accordingly. This study aims to (1) identify seismic and climate-change-induced (sea-level rising and wildfire) hazardous locations in the San Francisco Bay Area, and (2) examine whether all neighborhoods, in four dimensions (economic, social, land use, and capital investment), are equally exposed to each natural hazard at three spatial scales (county, region, the Bay) over two time periods (2020–2060, 2060–2099). Methodologically, the study region and its sub-regions were divided into hazard and non-hazard zones with a defined hazard level for three natural hazards. Vulnerability variables in the four dimensions were collected at the census tract level. A two-sample t-test was then conducted to examine whether each vulnerability variable was significantly different between the two zones (hazard and non-hazard) for a specific natural hazard at a specific spatial scale in a specific time period. The findings reveal where, who, and what are exposed to different natural hazards. Corresponding mitigation measures for local governments are suggested. The results also highlight whether the spatial pattern of each hazard changes over time and whether local governments should work on mitigation alone, cooperate with other counties, or act together.