Probabilistic Earthquake Forecasts and Public Perception: Thresholds, Cognitive Reflection, and Risk Communication in Japan

Abstract Probabilistic earthquake forecasts are central to preparedness, yet public interpretation remains poorly understood. This study examined perceived fear thresholds for seismic intensity, probability, and return‐period forecasts using the method of limits in an online survey of 1,113 Japanese homeowners in the Kansai area, and investigated individual differences in judgments and protective intentions. Distinct judgment patterns were observed for return periods at approximately 5, 10–19, and 100 years. Probability forecasts showed inflection points around 45%–54%, and by level 5‐upper on the Japanese seismic intensity scale, more than 80% of participants reported fear. Protective behavioral intentions were associated with gender, income, regional vulnerability, perceived probability, and Cognitive Reflection Test scores. Men reported lower perceived probabilities. Perceived fear followed a nonlinear and asymmetric pattern, peaking at mid‐range probabilities and declining more sharply at higher than lower levels. Protective behavioral intentions were more closely associated with comprehension and analytical reasoning than with perceived fear, indicating that individuals with higher Cognitive Reflection Test scores were more likely to incorporate probabilistic information when forming intentions. Return‐period formats appeared more interpretable than raw probability values by aligning risk with familiar time horizons. These findings highlight the value of forecasts that prioritize interpretability and deliberation over heightened fear.