Date of Award


Degree Type


Degree Name

Master of Engineering Science


Civil and Environmental Engineering


Professor Hanping Hong

Second Advisor

S. Banik


Probabilistic quantitative tornado hazard assessment is often based on the consideration that the spatial distribution of tornado occurrence is homogeneous in a region. While this assumption simplifies the analysis, it could over- and under- estimate tornado hazard for regions with lower and higher tomadic activity if an average rate of tornado occurrence is employed. The degree of over- and under-estimation is unknown. This study is focused on the assessment of the impact of spatial inhomogeneity of tornado occurrence on the estimated tornado hazard, and the development of tornado hazard maps for southern Ontario. The obtained results indicate that the tornado hazard at the factoted design wind speed level is much smaller than the wind hazard due to synoptic winds even if the spatial inhomogeneity of tornado occurrence is considered. Furthermore, the results show that the spatial inhomogeneity of tornado occurrence has significant impact on the spatial tornado hazard level, that the return period values of tornado wind speed vary significantly over the considered region, and that the inhomogeneity must be considered in developing probabilistic quantitative tornado hazard maps. Also, an attempt is made to assemble an approach for assessing the tornado hazard considering the uncertainty in the tornado occurrence rate in time and space. The quantification of this uncertainty is carried out by using the hierarchical Bayesian modeling and Markov Chain Monte Carlo technique. Results showed that it is feasible to use such an assembled approach to assess the tornado hazard maps, which incorporate the uncertainty in tornado occurrences.



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