UGRC 144 Science and Technology in Our Lives/Geohazards Session 1 Introduction to Hazards and Disasters Dr. Patrick Asamoah Sakyi Department of Earth Science, UG, Legon College of Education School of Continuing and Distance Education 2014/2015 2016/2017
Session Overview In everyday life, we always negatively associate events like earthquakes, tsunami and floods, with disasters. In this section; The terms disaster and hazard are defined and explained Explanation will be given as to why the mere occurrence of an event like an earthquake should not be regarded as the occurrence of a disaster. Also, the conditions under which an event becomes a disaster will be explained. Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 2
Session Outline The key topics to be covered in the session are as follows: Topic One - Hazard Topic Two - Classification of Hazards Topic Three - Vulnerability Topic Four - Disaster Topic Five - Disaster prevention and management Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 3
Reading List Read Chapter 4 of Environmental Geology 4 th Edition by Carla W Montgomery (1995) Read Unit 1, Section 1 of UGRC 140 II Geohazards Institute of Continuing and Distance Education Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 4
Topic One HAZARD Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 5
What is a Hazard Hazard is defined as: Phenomena that pose a threat to people, structures, or economic assets and which may cause a disaster. They could be either man-made or naturally occurring in our environment. A natural or man-made phenomenon that may cause physical damage, economic loss and threaten human life and wellbeing A trigger event. A trigger-event that sets off a disaster Hazard means an event which has the potential to cause a disaster, and can be either natural or man-made. Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 6
Topic Two CLASSIFICATION OF HAZARDS Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 7
Classification of Hazards Hazards are classified into two main groups, namely: natural hazards and man-made hazards. Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 8
Classification of Hazards There are two types of natural hazards, namely; fast-impact and slow-onset hazards, (e.g. chemical spill, fire), or technological in nature (e.g. nuclear generator failure). Examples of fast impact natural hazards include earthquakes, floods, cyclones, hurricanes, tornadoes, landslides, tsunami, volcanic eruption, insect infestation and wild-fires. Slow onset natural hazards include epidemics of biological origin (e.g. SARS, Bird Flu, Ebola), drought, and famine. Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 9
Classification of Hazards Man-made hazards are also of two types; sudden long term; Sudden man-made hazards include transport, structural and technological accidents (e.g. chemical spill, fire) Long term man-made hazards (e.g. nuclear generator failure). Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 10
Topic Three VULNERABILITY Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 11
What is Vulnerability Vulnerability is a term used to describe exposure to hazards and shocks. It is defined as the extent to which a community, structure, service, and/or geographic area is likely to be damaged or disrupted by the impact of a particular hazard, on account of their nature, construction and proximity to hazardous terrain or a disaster prone area. People are more vulnerable if they are more likely to be badly affected by events outside their control. For a disaster to occur the hazard must come in touch with unsafe conditions which make a population vulnerable to that particular hazard Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 12
Topic Four DISASTER Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 13
What is a Disaster A disaster is; A sudden, adverse event bringing great damage, loss, great distress, destruction and devastation to life and property. A serious disruption of the functioning of society, causing a calamity, widespread human, material or environmental losses which exceed the ability of the affected society to cope using its own resources. The disruption of human ecology that exceeds the capacity of the community to function normally (WHO). Sudden ecologic phenomenon of sufficient magnitude to require external assistance Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 14
What does a Disaster do? A disaster influences the mental, socio-economic, political and cultural state of the affected area. It completely disrupts the normal day to day life in a society It negatively influences the emergency systems Normal needs and processes like food, shelter, health, etc. are affected and deteriorate depending on the intensity and severity of the disaster Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 15
Topic Five DISASTER PREVENTION AND MANAGEMENT Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 16
How do we Prevent Disaster? We now know that: DISASTER = HAZARD + VULNERABILITY Human-induced hazards that can potentially result in a disaster can be avoided or prevented Naturally-occurring hazards cannot be entirely controlled, but disasters associated with them can be reduced by following certain directives. Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 17
How do we Prevent Disaster? To avoid, prevent or manage a disaster; Eliminate Hazard No Disaster Eliminate Vulnerability No Disaster Keep Hazard and Vulnerability Apart. Reduce Vulnerability and/or hazard, especially humaninduced hazard. The specific disaster prevention and/or management techniques will be discussed under each geological hazard in subsequent sections Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 18
Summary In this section; we have defined and explained; disaster, hazard and vulnerability. We have seen that hazards only result in a disaster if they coincide with vulnerable conditions. We have seen that to avoid a disaster, we must prevent a hazard from coming in contact with vulnerable societies. Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 19
END Dr. Patrick A. Sakyi, Dept. of Earth Science Slide 20