Big Data is one of the cutting-edge technologies that smart cities use to optimise resource management, guarantee sustainability, and improve urban living. However, a number of hazards are brought about by the intricacy of smart city ecosystems, such as data privacy issues, infrastructure weaknesses, and cybersecurity threats. The potential of big data to successfully anticipate, reduce, and respond to hazards is examined in this study as it relates to risk management in smart cities. We go over how to build strong risk management frameworks by combining Big Data analytics with IoT, AI, and machine learning. Practical applications are demonstrated through case studies and examples, and issues like data security, moral dilemmas, and scalability are discussed. Recommendations for legislators, urban planners, and technology companies to use Big Data for resilient and sustainable smart cities are included in the manuscript's conclusion.