DEFINITION: Conditional probability of an outcome given a set of data, assumptions and information. Also used as a qualitative description of probability and frequency ( Landslide Risk Management, editors Hungr et al, Balkema, 2005).
DEFINITION : A measure of the degree of certainty. This measure has a value between 0 (impossibility) and 1.0 (certainty). It is an estimate of the likelihood of the magnitude of the uncertain quantity, or the likelihood of the occurrence of the uncertain future event ( Landslide Risk Management, editors Hungr et al, Balkema, 2005).
For example , an earthquake above a certain intensity or a landslide of sufficient size, depth, or displacement to cause damage or disruption or, as an example of a situation, the presence of weak foundation material (Landslide Hazard and Risk, editors Glade, T. et al, 2006)
Explanation: This probability varies with the magnitude of the event (generally small landslides occur more frequently than large landslides). Consequently hazard is often expressed as the probability of occurrence of a given magnitude of event. Defined in this way, hazard represents a state or condition and is assessed and applied to a particular place, for example site, unit area of land surface, region or object, lifelines, hydro dams and so on (Landslide Hazard and Risk, editors Glade, T. et al, 2006) .
A potentially damaging physical event or phenomenon that may cause the loss of life or injury, property damage, social and economic disruption or environmental degradation (DRMP, Distt. Sialkot, DDMA, November, 2008)
Hazards are sometimes classified into three modes:
Dormant - The situation has the potential to be hazardous, but no people, property, or environment is currently affected by this. For instance, a hillside may be unstable, with the potential for a landslide , but there is nothing below or on the hillside that could be affected.
Armed - People, property, or environment are in potential harm's way.
Active - A harmful incident involving the hazard has actually occurred. Often this is referred to not as an "active hazard" but as an accident , emergency , incident, or disaster . (wikipedia)
A geologic hazard is an extreme natural events in the crust of the earth that pose a threat to life and property (Glossary of Environment Statistics, Studies in Methods, Series F, No. 67, United Nations, New York, 1997.)
RISK: A measure of the probability and severity of loss to the elements at risk, usually expressed for a unit area, object, or activity, over a specified period of time (Landslide Hazard and Risk, editors Glade, T. et al, 2006) .
The concept of vulnerability expresses the multidimensionality of disasters by focusing attention on the totality of relationships in a given social situation which constitute a condition that, in combination with environmental forces, produces a disaster (Wikipedia) .
VULNERABILITY : The degree of loss to a given element or set of elements within the area affected by a hazard. It is expressed on a scale of 0 (no loss) to 1 (total loss) (Landslide Risk Management, editors Hungr et al, Balkema, 2005).
VULNERABILITY: The conditions determined by physical, social, economic, and environmental factors or processes, which increase the susceptibility of a community to the impact of hazard (DRMP, Distt. Sialkot, DDMA, November, 2008).
LANDSLIDE SUSCEPTIBILITY : The propensity (tendency) of an area to undergo landsliding. It is the function of the degree of inherent stability of the slope (as indicated by the factor of safety or excess strength) together with presence of factors capable of reducing the excess strength and ultimately triggering movement (Landslide Hazard and Risk, editors Glade, T. et al, 2006).
A disaster is a natural or man-made (or technological) hazard that has come to fruition, resulting in an event of substantial extent causing significant physical damage or destruction, loss of life, or drastic change to the environment (Wikipedia).
A serious disruption of the functioning of a community or society causing widespread human, material, economic or environmental losses which exceed the ability of the affected community or society to cope using its own resources. DRMP, Distt. Sialkot, DDMA, November, 2008).