1.1 Definition and classification of disasters

Disasters are events that disrupt communities, causing widespread losses and overwhelming local resources. This topic explores how disasters are defined and classified, examining their key characteristics and categories like natural, human-made, and complex disasters.

Understanding disaster types is crucial for effective management. From geophysical and hydrological to meteorological and societal, each category presents unique challenges. By grasping these distinctions, we can better prepare for and respond to various disaster scenarios.

Defining Disasters

Key Characteristics and Classifications

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  Athabasca Glacier: a tragic vanishing act View original

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  Gully erosion as a natural and human-induced hazard | Natural Hazards View original

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• 

  The Nature of “Natural Disasters”: Survivors’ Explanations of Earthquake Damage | SpringerLink View original

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  Athabasca Glacier: a tragic vanishing act View original

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• A disaster is a serious disruption of the functioning of a community or society, causing widespread human, material, economic, or environmental losses that exceed the ability of the affected community or society to cope using its own resources
• Key characteristics of disasters include their sudden onset, widespread impact, and the need for external assistance to recover
• Disasters can be classified based on their speed of onset (sudden or slow), their duration (short-term or long-term), and their geographic spread (localized or widespread)
• Examples of sudden-onset disasters include earthquakes, tsunamis, and industrial accidents, while slow-onset disasters include droughts and climate change-related events
• Short-term disasters, such as hurricanes or floods, may last for days or weeks, while long-term disasters, such as droughts or conflicts, can persist for months or years

Disaster Categories

Natural Disasters

• Natural disasters are caused by natural hazards such as earthquakes, tsunamis, volcanic eruptions, landslides, hurricanes, floods, wildfires, and droughts
• These events are triggered by natural processes and forces, often with little or no human influence
• Examples of natural disasters include the 2010 Haiti earthquake, the 2004 Indian Ocean tsunami, and the 2019-2020 Australian bushfires
• The impact of natural disasters can be exacerbated by human factors, such as poor land-use planning, inadequate infrastructure, and lack of preparedness

Human-made Disasters

• Human-made disasters are caused by human actions, negligence, or error, and include industrial accidents, transportation accidents, oil spills, nuclear accidents, and acts of terrorism
• These disasters are the result of human decisions, activities, or failures in technology or infrastructure
• Examples of human-made disasters include the 1986 Chernobyl nuclear accident, the 2010 Deepwater Horizon oil spill, and the 9/11 terrorist attacks
• Human-made disasters can have long-lasting impacts on the environment, human health, and social and economic systems

Complex Disasters

• Some disasters, such as climate change-related events, can be attributed to a combination of natural and human factors
• These complex disasters involve the interaction of multiple hazards, vulnerabilities, and risks, making them challenging to predict and manage
• Examples of complex disasters include the impacts of climate change on coastal communities, such as sea-level rise, increased storm intensity, and saltwater intrusion
• Addressing complex disasters requires a holistic approach that considers the interconnected nature of natural and human systems

Disaster Types

Geophysical and Hydrological Disasters

• Geophysical disasters include earthquakes, tsunamis, volcanic eruptions, and landslides, which are caused by the movement of the Earth's crust and the release of energy from within the Earth
• Hydrological disasters include floods and flash floods, which are caused by excessive water due to heavy rainfall, rapid snowmelt, or the failure of dams or levees
• Examples of geophysical disasters include the 2011 Tōhoku earthquake and tsunami in Japan and the 2018 Anak Krakatau volcanic eruption and tsunami in Indonesia
• Examples of hydrological disasters include the 2005 Hurricane Katrina flooding in New Orleans and the 2021 European floods affecting Germany, Belgium, and the Netherlands

Meteorological and Climatological Disasters

• Meteorological disasters include hurricanes, cyclones, and storms, which are caused by extreme weather conditions such as high winds, heavy rainfall, and storm surges
• Climatological disasters include droughts, heat waves, and wildfires, which are caused by long-term changes in weather patterns and temperature extremes
• Examples of meteorological disasters include Hurricane Maria in Puerto Rico (2017) and Cyclone Idai in Mozambique (2019)
• Examples of climatological disasters include the 2018 California wildfires and the 2019-2020 Australian bushfires

Biological and Technological Disasters

• Biological disasters include epidemics and pandemics, which are caused by the rapid spread of infectious diseases among populations
• Technological disasters include industrial accidents, transportation accidents, and oil spills, which are caused by equipment failure, human error, or negligence
• Examples of biological disasters include the ongoing COVID-19 pandemic and the 2014-2016 West African Ebola epidemic
• Examples of technological disasters include the 1984 Bhopal gas tragedy in India and the 2011 Fukushima Daiichi nuclear disaster in Japan

Societal Disasters

• Societal disasters include acts of terrorism, civil unrest, and war, which are caused by intentional human actions aimed at causing harm and disruption
• These disasters often have complex political, social, and economic roots and can lead to widespread human suffering, displacement, and loss of life
• Examples of societal disasters include the Syrian civil war, which began in 2011, and the Rohingya refugee crisis in Myanmar and Bangladesh
• Addressing societal disasters requires a multi-faceted approach that addresses the underlying causes of conflict and promotes peace, justice, and reconciliation

Hazards and Disasters

Understanding Hazards

• A hazard is a potential source of harm or adverse impact on people, property, or the environment
• Hazards can be natural, such as earthquakes or hurricanes, or human-made, such as chemical spills or nuclear accidents
• The severity of a hazard is determined by its intensity, duration, and geographic extent
• Examples of natural hazards include seismic activity, volcanic eruptions, and extreme weather events, while human-made hazards include industrial accidents, transportation incidents, and acts of violence

Relationship between Hazards and Disasters

• The relationship between hazards and disasters is determined by the vulnerability and exposure of people, property, and systems to the hazard
• A hazard becomes a disaster when it interacts with vulnerable populations or infrastructure, causing significant damage and disruption
• Vulnerability refers to the characteristics and circumstances of a community, system, or asset that make it susceptible to the damaging effects of a hazard
• Exposure refers to the presence of people, livelihoods, environmental services and resources, infrastructure, or economic, social, or cultural assets in places that could be adversely affected by a hazard

Risk and Resilience

• Risk is the combination of the probability of a hazardous event occurring and the severity of its potential consequences
• Disaster risk management aims to reduce the likelihood and impact of disasters by addressing both hazards and vulnerabilities
• This involves identifying, assessing, and reducing risks through measures such as hazard mapping, early warning systems, land-use planning, and building codes
• Resilience is the ability of a system, community, or society to resist, absorb, accommodate, adapt to, transform, and recover from the effects of a hazard in a timely and efficient manner
• Building resilience involves strengthening the capacity of individuals, communities, and institutions to anticipate, prepare for, respond to, and recover from disasters
• Examples of resilience-building measures include community-based disaster risk reduction, ecosystem-based adaptation, and social protection programs