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close this bookAn Overview of Disaster Management (Department of Humanitarian Affairs/United Nations Disaster Relief Office - United Nations Development Programme , 1992, 136 p.)
close this folderChapter 4. Natural hazards
close this folderCharacteristics of particular hazards and disasters 1
View the document(introduction...)
View the documentEarthquakes
View the documentTsunamis
View the documentVolcanoes
View the documentLandslides
View the documentTropical cyclones
View the documentFloods
View the documentDroughts
View the documentEnvironmental pollution
View the documentDeforestation
View the documentDesertification
View the documentPest infestations
View the documentEpidemics
View the documentChemical and industrial accidents


1 The following material on hazards and population displacements is drawn from the UNDP/UNDRO Disaster Management Manual.

This section provides an indication of the general characteristics of each of the hazard types listed and the kinds of counter-disaster measures which may be required. You should note that disasters have collateral or indirect effects that may endure even after a particular type of disaster has been directly addressed. The problem of displaced people after a sudden onset disaster, such as a cyclone, may continue well after immediate relief, recovery and even rehabilitation programmes have been implemented. Such collateral impact can turn a seemingly rapid onset disaster into a continuing emergency situation.

A further issue that must be borne in mind concerns the consequence of a sudden onset disaster when relief assistance is stymied because civil conflict makes access impossible. In other words, the perverse permutations are many. Nevertheless, the basic characteristics of certain types of disasters and emergencies and appropriate response measures can be structured as follows:

Causal phenomena

General characteristics


Factors contributing to vulnerability

Typical effects

Possible risk reduction measures

Specific preparedness measures

Typical post-disaster needs

Different types of disasters have characteristic effects while retaining unique aspects. Risk reduction and preparedness measures, and emergency and post-disaster response can all be facilitated by some “rules of thumb” - as outlined in this section - but must also be tailored to the specificity of local conditions.


(a) where different types of disaster occur in combination - e.g. floods accompanying tropical storms - the combined effects must be considered; and where one disaster leads to another (for example a famine leading to civil strife) the compound effects must be anticipated

(b) the severity of the actual impact on the society depends on human and organizational factors as well as natural and topographical ones.

Figure 4.1 World map of selected hazards


Volcanic eruptions

Shorelines exposed to tsunami waves

Seismic belts

Land areas affected by tropical cyclones

Desertification likely or active