"one of the most significant contemporary security challenges has been the increased focus on emergency, crisis, and disaster management--a task that includes preparation for and response to catastrophic events, including droughts, famines, floods, fires, explosions, pandemics, volcanic eruptions, earthquakes, tsunamis, winter storms, and other disasters" (Smith, Schmalleger, & Siegel, 2017). What are the main causes of these and can you provide a specific example from history?