Determining acceptable risk levels in earthquake disasters: insights from Chinese Mainland

The establishment of acceptable risk standards serves as a crucial connection between earthquake disaster risk assessment and risk management. Currently, there lacks a standardized criterion for determining the acceptable level of risk pertaining to earthquake disasters. To establish a standardized system of acceptable risk of earthquake disaster, the data of disaster-affected toll, death toll, and direct economic losses resulting from earthquakes disaster with M_S ≥ 5.0 in Chinese Mainland between 1991 and 2020 are utilized. These data are employed to construct the acceptable life risk F–N curve (the accumulated probability F of annual death toll ≥ N—death toll N), the acceptable economic risk F–D curve (the accumulated probability F of annual direct economic losses ≥ D—direct economic losses), and the acceptable comprehensive risk F–L curve (the accumulated probability F with earthquake occurrence of annual disaster degree ≥ L—disaster degree). Then, the acceptable risk level of earthquake disasters with M_S5.0–5.9, M_S6.0–6.9, M_S ≥ 7.0, and M_S ≥ 5.0 are determined. Moreover, the classification and consistency of acceptable types of earthquake disaster comprehensive risk, life risk and economic risk in the past 30 years are compared. Through analysis, the acceptable life risk, acceptable economic risk, and acceptable comprehensive risk criteria of earthquake disasters with M_S5.0–5.9, M_S6.0–6.9, M_S ≥ 7.0, and M_S ≥ 5.0 in Chinese Mainland are obtained. It is found that the comprehensive risk of earthquake disasters with different magnitudes is mainly at an unacceptable level, while the main types that are consistent with life risk and economic risk are tolerable level and acceptable level, respectively. The research results can provide more comprehensive theoretical data and practical basis for the effective implementation of earthquake disaster risk management.