Systematic evaluation on urban disaster risks

The evaluation on urban disaster risks from system angle is very useful in its research.The feasibility of method of brittleness risk entropy used in urban disaster system risk analysis is first discussed,and the factors of brittleness and brittle events’ results are then confirmed from both aspects of hazards and vulnerability.Due to the inveracity of statistical probability with little sample of disasters,the mutation progression was used to calculate the probability instead of the statistical probability and fuzzy degree instead of brittle events’ value.The brittleness risk entropy based on entropy theory is the integrated estimation of mutation probability of brittle factors and value of brittle events’ results as well as the urban disasters risk.