From the Syllabus
5.c. The Exposure of people to risks and their ability to cope with tectonic hazards changes over time.
- How and why have the risks from tectonic hazards changed over time including:
- changes in the frequency and impacts of tectonic hazards over time.
- the degree of risk posed by a hazard and the probability of the hazard event occurring (the disaster risk equation).
- possible future strategies to cope with risks from tectonic hazards.
- The relationship between disaster and responses including the Park model.
Changes in Tectonic Hazards Over Time
The graph above shows that the number of natural disasters has increased over time, though the number of geophysical (tectonic) disasters has increased very little, particularly when compared to hydro-metrological (floods and severe weather).
The increase in floods and severe weather can be explained through the interaction of physical and human factors. Human activities such as urbanisation can have a direct causation of events such as flooding. Whereas geophysical events (earthquakes and volcanoes) are not caused by human activity. However human activity does have an impact on the impact of seismic and volcanic hazard events.
Frequency – the distribution of the hazard through time.
Magnitude – the size of the impact.
The Disaster Risk Equation
Geophysical events such as volcanic eruptions and earthquakes become hazards when they pose a risk to people. A disaster is an actual event, which usually involves loss of life and a great deal of damage to the human environment.
The disaster risk equation gives an indication of the hazard vulnerability for a location:
The exposure to earthquakes and volcanic hazards depends on:
- Frequency of earthquakes and volcanic activity.
- Magnitude of earthquakes and volcanic activity.
- Types of hazards generated by earthquakes and volcanoes in a particular location.
- Number of people living in an earthquake -prone and/or an eruption-prone area.
Vulnerability – the ability of a person or community to withstand exposure to, and risks from, a hazard such as an earthquake or volcanic eruption.
Resilience – the indication of the rate or recovery from a hazardous event that has put an individual and/ or community under stress.
Future Strategies to Cope with Risks from Tectonic Hazards
There are a number of different strategies that can be used to manage tectonic hazards:
- Modifying the Hazard Event
- Modifying Vulnerability and Resilience (at an individual, community and country scale)
- Modifying Loss
The Park Model
Park’s Disaster Response Curve (1991) can be used as a framework to help better understand the time dimensions of recovering from a disaster – from a hazard striking to when a place, community or country returns to normal.
Each stage on the x-axis shows the different stages of time during which either relief, rehabilitation or reconstruction is tarted. The words on the y-axis describe the quality of life, stability and infrastructure.
The Park Model or Disaster response curve is specified in the syllabus by the exam board; this means that you should know it – ideally, you should be able to know it well enough to be able to draw it from memory.
The Stages in the Disaster Response Curve
Stage 1 – Pre-Disaster – Quality of life is normal. People do their best to prevent and prepare for such events happening, for example by educating the public on how to act when disaster strikes, preparing supplies, putting medical teams on standby, and so on [this will be difficult depending on the nature of the hazard and the country].
Stage 2 – Disaster / Hazardous Event
Stage 3 – Search/Rescue and Care – The hazardous event has occurred – immediate relief is the priority with medical attention, rescue services and emergency care provided. This period of time can last from hours to a number of days. The quality of life has seemingly stoped decreasing and is beginning to move up slowly.
Stage 4 – Relief and Rehabilitation – Groups try to return the state of things back to normal, by providing food, water and shelter to those who are without these basic needs.
Stage 5 – Reconstruction – In the longer term rehabilitation moves into the reconstruction period during which infrastructure, crops and property are invested in. During this time organisations may use preparation and prevention to improve from the mistakes of this disaster to respond better to the next one.