Fires following the 2024 Noto Peninsula earthquake: Insights from ignition records, a fire damage survey, and a prospective regional fire risk assessment

Rupture of an active fault across the Noto Peninsula, Japan, generated a moment magnitude 7.5 earthquake on 1 January 2024 causing multiple cascading hazards with significant impacts on communities. This study focuses on the fire‐following‐earthquake aspects of the 2024 Noto Peninsula earthquake. Along with a summary of ignition records collected from municipal fire departments and field observations in several large fire‐affected areas, the fire‐following‐earthquake risk that would have been estimated for the building stock is quantified using a hypothetical earthquake source model developed prior to the earthquake. Using this case study, the effect of future climate change on regional fire‐following‐earthquake risk assessments is also investigated. The 17 fires following the earthquake included both shaking‐induced and tsunami‐induced fires, 3 of which enlarged significantly outside and within the tsunami inundation zone. The two fires within the tsunami inundation zone started from an inundated building and an inundated automobile and spread to 18 tsunami‐inundated buildings in total. The inferred ignition rate for the shaking‐induced fires, mostly from electricity‐related ignition sources, was high relative to recent large earthquakes in Japan. Conventional factors, including delayed fire detection, unavailable fire hydrants resulting from seismic damage to water supply systems, and inaccessible fire cisterns resulting from collapsed buildings, led to a large fire in downtown Wajima that destroyed ~240 buildings. This fire loss corresponded to a 1.9% conditional exceedance probability according to 6000 stochastically synthesized fire‐following‐earthquake scenarios. Typical meteorological year data based on global warming projections allow synthetic future hourly weather parameter values to be linked to long‐term probabilistic fire losses, revealing that the average increases in hourly air temperature and wind velocity and average decreases in hourly relative humidity in future climate change projections can increase fire loss exceedance probabilities. These findings emphasize that further efforts to reduce the risk of fires following earthquakes are essential.