Types of hazards

Unit - V

Natural Disasters

Seismology and Seismic waves Earth quake ground motion Basic concepts and estimation techniques - site effects Probabilistic and deterministic Seismic hazard analysis Cyclone and flood hazards - Fire hazards and fire protection, fire-proofing of materials, fire safety regulations and fire fighting equipment - Prevention and safety measures.

Introduction

Certain natural phenomena produce environmental disequilibrium or disaster or hazards causing large-scale destruction of human life and property. These hazards are accidental, and mostly, humans do not play a significant role in these.

However, some times, human activities accelerate the process. Hazard management is an important issue that needs serious consideration.

Some of the hazards which cause environmental degradation are earth-quakes, cyclones, landslides, drought, famines, etc.

The magnitude and frequency of these processes depend on factors such as climate, geology, vegetation, and human activities.

Types of hazards

Hazards are classified into two types:

(i) Natural hazards

(ii) Anthropogenic hazards.

Natural hazards

• Air-related hazards: Hurricanes, cyclones, storms, etc.

• Water-related hazards: Floods, droughts, etc.

• Earth-related hazards: Earthquakes, landslides, volcanoes, etc.

Anthropogenic hazards

• Industrial accidents

• War, riots, acts of terrorism, etc.

• Toxic spills

Some of the hazards, their causes, effects, and management techniques are discussed in the following sections.