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 happens, disaster response (e.g. emergency evacuation, quarantine, mass decontamination, etc.), as well as 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. 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. The academic trend is towards using the more comprehensive term disaster risk reduction, particularly for emergency management in a development management context.
 Phases and professional activities
The nature of emergency management is highly dependent on economic and social conditions local to the emergency, or disaster. This is true to the extent that some disaster relief experts such as Fred Cuny have noted that in a sense the only real disasters are economic.  Experts, such as Cuny, have long noted that the cycle of emergency management must include long-term work on infrastructure, public awareness, and even human justice issues. This is particularly important in developing nations. The process of emergency management involves four phases: mitigation, preparedness, response, and recovery.
A graphic representation of the four phases in emergency management.
Mitigation efforts attempt to prevent hazards from developing into disasters altogether, or to reduce the effects of disasters when they occur. The mitigation phase differs from the other phases because it focuses on long-term measures for reducing or eliminating risk. The implementation of mitigation strategies can be considered a part of the recovery process if applied after a disaster occurs. However, even if applied as part of recovery efforts, actions that reduce or eliminate risk over time are still considered mitigation efforts.
Mitigative measures can be structural or non-structural. Structural measures use technological solutions, like flood levees. Non-structural measures include legislation, land-use planning (e.g. the designation of nonessential land like parks to be used as flood zones), and insurance. Mitigation is the most cost-efficient method for reducing the impact of hazards. However, mitigation is not always suitable and structural mitigation in particular may have adverse effects on the ecosystem.
A precursor activity to the mitigation is the identification of risks. Physical risk assessment refers to the process of identifying and evaluating hazards. In risk assessment, various hazards (e.g. earthquakes, floods, riots) within a certain area are identified. Each hazard poses a risk to the population within the area assessed. The hazard-specific risk (Rh) combines both the probability and the level of impact of a specific hazard. The equation below gives that the hazard times the populations’ vulnerability to that hazard produce a risk. Catastrophe modeling tools are used to support the calculation. The higher the risk, the more urgent that the hazard specific vulnerabilities are targeted by mitigation and preparedness efforts. However, if there is no vulnerability there will be no risk, e.g. an earthquake occurring in a desert where nobody lives.
In the preparedness phase, emergency managers develop plans of action for when the disaster strikes. Common preparedness measures include the
communication plans with easily understandable terminology and chain of command
development and practice of multi-agency coordination and incident command
proper maintenance and training of emergency services
development and exercise of emergency population warning methods combined with emergency shelters and evacuation plans
stockpiling, inventory, and maintenance of supplies and equipment
An efficient preparedness measure is an emergency operations center (EOC) combined with a practiced region-wide doctrine for managing emergencies. Another preparedness measure is to develop a volunteer response capability among civilian populations. Since, volunteer response is not as predictable and planable as professional response, volunteers are most effectively deployed on the periphery of an emergency.
Another aspect of preparedness is casualty prediction, the study of how many deaths or injuries to expect for a given kind of event. This gives planners an idea of what resources need to be in place to respond to a particular kind of event.
The response phase includes the mobilization of the necessary emergency services and first responders in the disaster area. This is likely to include a first wave of core emergency services, such as firefighters, police and ambulance crews. They may be supported by a number of secondary emergency services, such as specialist rescue teams.
In addition volunteers and non-governmental organizations (NGOs) such as the local Red Cross branch or St. John Ambulance may provide immediate practical assistance, from first aid provision to providing tea and coffee. A well rehearsed emergency plan developed as part of the preparedness phase enables efficient coordination of rescue efforts. Emergency plan rehearsal is essential to achieve optimal output with limited resources. In the response phase, medical assets will be used in accordance with the appropriate triage of the affected victims.
Where required, search and rescue efforts commence at an early stage. Depending on injuries sustained by the victim, outside temperature, and victim access to air and water, the vast majority of those affected by a disaster will die within 72 hours after impact.
Individuals are often compelled to volunteer directly after a disaster. Volunteers can be both a help and a hindrance to emergency management and other relief agencies.
The aim of the recovery phase is to restore the affected area to its previous state. It differs from the response phase in its focus; recovery efforts are concerned with issues and decisions that must be made after immediate needs are addressed. Recovery efforts are primarily concerned with actions that involve rebuilding destroyed property, re-employment, and the repair of other essential infrastructure. An important aspect of effective recovery efforts is taking advantage of a ‘window of opportunity’ for the implementation of mitigative measures that might otherwise be unpopular. Citizens of the affected area are more likely to accept more mitigative changes when a recent disaster is in fresh memory.
In the United States, the National Response Plan dictates how the resources provided by the Homeland Security Act of 2002 will be used in recovery efforts. It is the Federal government that often provides the most technical and financial assistance for recovery efforts in the United States.
 Phases and personal activities
Personal mitigation is mainly about knowing and avoiding unnecessary risks. This includes an assessment of possible risks to personal/family health and to personal property.
One example of mitigation would be to avoid buying property that is exposed to hazards, e.g. in a flood plain, in areas of subsidence or landslides. Homeowners may not be aware of a property being exposed to a hazard until it strikes. However, specialists can be hired to conduct risk identification and assessment surveys. Purchase of insurance covering the most prominent identified risks is a common measure.
Personal structural mitigation in earthquake prone areas includes installation of an Earthquake Valve to instantly shut off the natural gas supply to a property, seismic retrofits of property and the securing of items inside a building to enhance household seismic safety. The latter may include the mounting of furniture, refrigerators, water heaters and breakables to the walls, and the addition of cabinet latches. In flood prone areas houses can be built on poles, as in much of southern Asia. In areas prone to prolonged electricity black-outs installation of a generator would be an example of an optimal structural mitigation measure. The construction of storm cellars and fallout shelters are further examples of personal mitigative actions.
See also hurricane preparedness and earthquake preparedness
Unlike mitigation activities, which are aimed at preventing a disaster from occurring, personal p