A hazard vulnerability assessment (HVA) systematically evaluates the damage that could be caused by a potential disaster, the severity of the impact, and the available medical resources during a disaster to reduce population vulnerability and increase the capacity to cope with disasters.
Disasters occur frequently and often place a substantial burden on affected populations. Disasters are defined as singular large-scale events that cause serious disruptions of the function of a community or a society and involve human, material, economic or environmental losses or impacts. Those losses or impacts often exceed the community’s or society’s ability to control or cope with the disaster using its existing resources. Disasters are the product of a combination of hazards and vulnerability. Hazards that strike in areas with low vulnerability will not become disasters. However, most hazards occur in developing or underdeveloped regions or in areas with a high population density, poor infrastructure, and a limited or no disaster preparedness plan. Comparing to developed countries, such as the U.S., where emergency planning and other disaster-related fields have been extensively studied and implemented, disaster-related fields such as disaster medicine education and research are fairly new in India. There is a significant gap between the knowledge level of and skills for disaster medicine and the current needs of disaster preparedness. High vulnerability and insufficient disaster preparedness plans have severe consequences.
Vulnerability
Vulnerability is defined as “the characteristics of a person or group and their situation that influences their capacity to anticipate, cope with, resist, and recover from the impact of a hazardous event". Vulnerability represents the susceptibility of a given population to harmful effects from exposure to hazardous events. It directly affects disaster preparation, response, and recovery. Hazardous event can directly or indirectly affect the health status of an individual or a population. There are two key components of a hazard’s definition: the extent of the influence (harm) caused by the exposure to the disaster and the “differential” sensitivity to and ability to recover from the disaster. Different populations have different levels of vulnerability to a hazardous event that depend on multiple uncertain factors, including hazard intensity, environment, and population characteristics. Hazard intensity is exposure related, which is directly related to the occurrence of natural disasters, such as heavy rainfall that may cause floods and/or landslides. Environmental and population characteristics are system-resistance factors related to population vulnerability level. Environmental factors can amplify or mitigate the destructive power of a hazardous event. For example, good water-soil conservation capabilities can reduce the effects of a mudslide. Social vulnerabilities are related to environmental and population characteristics, which are influenced by exposure, sensitivity, and resilience. Exposure is related to hazard proximity and the environmental characteristics. Sensitivity refers to the ability of an individual or community to protect itself from different types of potential harm, while resilience indicates an individual’s or community’s coping and adaptive capacities during and after a disaster. Vulnerable populations usually include those with low incomes; individuals who may be chronically or terminally ill, physically or mentally disabled, homeless, or uninsured or underinsured; and the elderly, children, and pregnant women. One ongoing area of vulnerability is the surge capacity for large-scale events.
Policies aimed at disaster prevention and rescue must take into consideration the hazard intensity, environmental, and population characteristics that will affect the impact and outcomes of a disaster. The changes of a population’s living environment will influence the population’s “absorbing” ability regarding the damage. The factors affecting the “absorbing” ability are generally classified into two categories. One is at the community level and includes such factors as population growth and distribution, especially increased population density and urbanization, deforestation, dense infrastructure, traffic congestion, river dredging, hospital distribution, socioeconomic status, occupation, and daily activity patterns and habitats. For example, with the rapid urbanization in India, the population is heavily weighted toward the eastern part of the country, which leads to a series of issues that include insufficient public health resources and infrastructure. The second category is at the national and international levels and includes such factors as global climate change, international debt relief policy, domestic land development plan, infrastructure of transportation and communication, government stability, execution of laws, public health policies, and population education level. All of these factors can be used to assess population vulnerability.
Hazard vulnerability assessment
Population hazard vulnerability analysis has been extensively studied and proven to be effective. A hazard vulnerability assessment (HVA) is a systematic approach to identify all possible hazards that may affect a specific population, assess the risk associated with each hazard (e.g., the probability of hazard occurrence and the consequences for the population), and study the findings to develop a prioritized comparison of hazard vulnerabilities. The consequence, or vulnerability, is related to both the impact on the population and the likely service demands created by the impact.
In addition, the military is always at the forefront of a disaster response. When disaster strikes, rapid, coordinated and appropriate responses are needed to mitigate the crisis and ensure the effective delivery of relief and aid. Military forces have the manpower, equipment, training and organization for an immediate and effective disaster response. Humanitarian relief has become a core task for defense forces.
Disaster identification
Hazard identification is an important step in an HVA. It includes determining the likelihood of a disaster occurring, its intensity and magnitude, and the possible affected areas of a community.
Disaster probability and consequences
In addition to type of disaster (e.g., natural, manmade, or technological), the impact of a particular hazardous event is also determined by likelihood (probability of occurrence or frequency), severity (magnitude and intensity), and population resilience (defined as “a measure to determine the impact of available public health, emergency management, and governmental and societal resources and capabilities that could potentially mitigate negative population health consequences”). Although no indicator can accurately predict the occurrence of disasters, the combination of different risk factors can help to predict the likelihood of disaster occurrence.
The likelihood of disaster occurrence can be described as low, medium, or high.
Other related factors that can be used to describe the probability include:
(1) the frequency of the occurrence of disaster-associated factors. For example, frequent and heavy rainfall indicates a high probability of floods;
(2) the location of the hazardous event. The closer the distance between the hazard and the community, the more severe the consequence may be to the nearby community; and
(3) seasonal or cyclical variations. The consequences of a disaster on the community mainly include three impacts: human, property, and business.
HVA methods
The assessment of hazard vulnerability is very helpful in emergency management. An emergency management geographic information system (GIS), including a vulnerability assessment, has been developed and applied successfully. Using socioeconomic and environmental data sources in the GIS, risk maps highlighting the potential impact of disasters on people and infrastructure can be developed that can provide guidance in terms of resource allocation and recovery operations.
Natural disasters, such as floods or cyclones, will become more frequent. The probability of manmade or technological disasters is also increasing. The challenge that lies ahead is immense.
The development, implementation and maintenance of a robust disaster preparedness plan needs great collaboration and synergy between different operational agencies and academic and training institutions. It is also important to merge academic advancement and expertise with practical field application.
