A natural hazard is a threat of a naturally occurring event will have a negative effect on humans. This negative effect is what we call a natural disaster. In other words when the hazardous threat actually happens and harms humans, we call the event a natural disaster.
Natural Hazards (and the resulting disasters) are the result of naturally occurring processes that have operated throughout Earth's history.
Effects of Hazards
Hazardous process of all types can have primary, secondary, and tertiary effects.
Primary Effects occur as a result of the process itself. For example water damage during a flood or collapse of buildings during an earthquake, landslide, or hurricane.
Secondary Effects occur only because a primary effect has caused them. For example, fires ignited as a result of earthquakes, disruption of electrical power and water service as a result of an earthquake, flood, or hurricane, or flooding caused by a landslide into a lake or river.
Tertiary Effects are long-term effects that are set off as a result of a primary event. These include things like loss of habitat caused by a flood, permanent changes in the position of river channel caused by flood, crop failure caused by a volcanic eruption etc.
Vulnerability to Hazards and Disasters
Vulnerability refers the way a hazard or disaster will affect human life and property Vulnerability to a given hazard depends on:
Proximity to a possible hazardous event
Population density in the area proximal to the event
Scientific understanding of the hazard
Public education and awareness of the hazard
Existence or non-existence of early-warning systems and lines of communication
Availability and readiness of emergency infrastructure
Cultural factors that influence public response to warnings
Construction styles and building codes
There are three main types of "earthquake proof" building structures, all used in Japan over the past decade. The first has a