Emergency management (or disaster management) is the discipline of dealing with and avoiding risks.It is a discipline that involves preparing for disaster before it occurs, disaster response (e.g., emergency evacuation, quarantine, mass decontamination, etc.), and supporting, and rebuilding society after natural or human-made disasters have occurred. In general, any Emergency management is the continuous process by which all individuals, groups, and communities manage hazards in an effort to avoid or ameliorate the impact of disasters resulting from the hazards. Actions taken depend in part on perceptions of risk of those exposed.Effective emergency management relies on thorough integration of emergency plans at all levels of government and non-government involvement. Activities at each level (individual, group, community) affect the other levels. It is common to place the responsibility for governmental emergency management with the institutions for civil defense or within the conventional structure of the emergency services. However, emergency management actually starts at the lowest level and only increases to the next higher organizational level after the current level's resources have been exhausted. In the private sector, emergency management is sometimes referred to as business continuity planning.

Emergency Management is one of a number of terms which, since the end of the Cold War, have largely replaced Civil defense, whose original focus was protecting civilians from military attack. Modern thinking focuses on a more general intent to protect the civilian population in times of peace as well as in times of war. Another current term, Civil Protection is widely used within the European Union and refers to government-approved systems and resources whose task is to protect the civilian population, primarily in the event of natural and human-made disasters. Within EU countries the term Crisis Management emphasises the political and security dimension rather than measures to satisfy the immediate needs of the civilian population.[citation needed] An academic trend is towards using the term disaster risk reduction, particularly for emergency management in a development management context. 

http://en.wikipedia.org/wiki/Emergency_management