Natural disasters such as earthquakes, tsunamis, landslides and volcanic activities has had devastating effects on human life. Risk is the probability of harmful consequences from the interaction of hazards and vulnerable conditions. With increasing numbers of people living in crowded cities and other vulnerable areas, it is more important than ever to advance our understanding of natural disasters and the ways in which humans respond to them. My interdisciplinary study reflected in my thesis includes integrated research on the risk assessment methods for natural hazards with focus on earthquake disasters. This thesis address firstly the development of a scaled risk assessment framework, comparative assessment of natural hazard losses, including respective case studies and global overview of natural hazard risk, and secondly a comparative risk assessment of geological disasters to elaborate the major disastrous hazards for global population. Furthermore, I evaluate the effect of past events in form of the number of losses with respect to the exposed population on the proneness of people to the disaster. I summarize acceptable risk criteria and the necessity of having a normalized framework for societal risk assessment. I evaluate the natural hazard risk assessment and acceptable risk criteria of 32 European countries. I also introduce the concept of resistance in both risk equation and in FN-curves. Resistance is the societal resilience of a society to the occurrence of a natural disaster. Moreover, using components of FN-curves (slopes and intercepts) for risk assessment of geological disasters based on real data, I showed that the world has been more at risk of earthquakes than tsunamis, volcanic activities and landslides since 1600. Also. based on the earthquake disasters data (1973-2010), I evaluated the temporal trend of hazard, risk, exposure and resistance of the world towards earthquake disasters. Our results does not provide any evidence of increase or decrease in the temporal trend of fatality rate and earthquake resistance while there is a significant decrease in the crude death rate. Finally, we evaluated the reliability of earthquake disaster system during 1950-2012 using probability of more than 1000 fatalities as probability of failure. Our yearly estimate of reliability at the beginning of each mission year shows that the avreage reliability of earthquake disaster system is very low (~0.3) and it is decreasing over time, too.

The occurrence of catastrophic incidents in the process industry leave a marked legacy of resulting in staggering economic and societal losses incurred by the company, the government and the society. The work described herein is a novel approach proposed to help predict and mitigate potential catastrophes from occurring and for understanding the stakes at risk for better risk informed decision making. The methodology includes societal impact as risk measures along with tangible asset damage monetization. Predicting incidents as leading metrics is pivotal to improving plant processes and, for individual and societal safety in the vicinity of the plant (portfolio). From this study it can be concluded that the comprehensive judgments of all the risks and losses should entail the analysis of the overall results of all possible incident scenarios. Value-at-Risk (VaR) is most suitable as an overall measure for many scenarios and for large number of portfolio assets. FN-curves and F$-curves can be correlated and this is very beneficial for understanding the trends of historical incidents in the U.S. chemical process industry. Analyzing historical databases can provide valuable information on the incident occurrences and their consequences as lagging metrics (or lagging indicators) for the mitigation of the portfolio risks. From this study it can be concluded that there is a strong statistical relationship between the different consequence tiers of the safety pyramid and Heinrich‘s safety pyramid is comparable to data mined from the HSEES database. Furthermore, any chemical plant operation is robust only when a strategic balance is struck between optimal plant operations and, maintaining health, safety and sustaining environment. The balance emerges from choosing the best option amidst several conflicting parameters. Strategies for normative decision making should be utilized for making choices under uncertainty. Hence, decision theory is utilized here for laying the framework for choice making of optimum portfolio option among several competing portfolios. For understanding the strategic interactions of the different contributing representative sets that play a key role in determining the most preferred action for optimum production and safety, the concepts of game theory are utilized and framework has been provided as novel application to chemical process industry.