Effects of natural disasters
The effects of natural disasters are many and varied. Some are short term effects that can be fixed with relative ease while others last for years. Natural disasters have three general types of effects: primary effects, secondary effects, and tertiary effects.
• Primary effects are the direct result of the natural disaster, such as collapsed buildings and water damage.
• Secondary effects are the result of primary effects. Examples of secondary effects include power outages due to fallen trees or damaged building and fires from broken gas lines. In these examples, the fallen trees and the damaged building would be primary effects that caused the power outages and fires (secondary effects).
• Tertiary effects are the long term effects of natural disasters. These include changes in the landscape and natural features, loss of habitat, and crop failure or reduction due to cooler temperatures or other interference.
Human responses to natural hazards
Humans have always had to deal with natural hazards; whether through preparing for them or responding when a disaster occurs. One of the most important ways humans respond to natural hazards is by preparing for their occurrence. As technology has improved, so has the ability to prepare, predict, and forecast future natural disasters.
• Hazard assessment is when scientists study natural hazards to determine characteristics of various hazards. A hazard assessment differs from a risk assessment primarily because and hazard assessment focuses mainly on the natural processes of a possible event while a risk assessment includes a hazard’s possible effects on a society. Hazard assessment generally determines the location and timing of past hazardous processes, the severity and frequency of past hazardous processes, probable effects of different processes depending upon the magnitude (severity) of a possible event, and organizing the information into a usable form for officials and policy makers.
• Risk assessment incorporates the information from a hazard assessment, but also includes possible socio-economic effects. A risk assessment includes locations of buildings and infrastructure in hazardous areas, the potential for exposure due to the physical effects of a hazard, community vulnerability in the event a hazard becomes a disaster, and a hazard assessment.
• A prediction is a statement of probability that an event will occur. In terms of natural hazards, predictions are made through various scientific observations. A common observation that could lead to a prediction is the identification of a precursor event. A precursor event is a smaller event that usually precedes a larger event, such as tropical depression leading to a tropical storm before becoming a hurricane or numerous small earthquakes around a volcano indicating an imminent eruption.
• Forecasting is similar to a prediction and is often used synonymously; however, in certain instances a forecast can be slightly different from a prediction. The term forecast is usually used as a short-term prediction of the severity, location, and timing of weather related events. It can also be used for long-term probabilities of an event occurring within a certain time frame. This long term forecasting is not as precise as a weather forecast.