An earthquake is sudden motion or trembling of the ground produced by the abrupt displacement of rock masses.
HOW DO THEY OCCUR?
The earth's outer shell is divided into seven major and some smaller plates which are constantly in a dynamic state, pushing against, pulling away from, or grinding past one another. Forces build up as the plates attempt to move in relation to each other. When the adhesions along the fault give way, stored energy is released in the form of earth tremors, volcanic activity etc.
Social Impacts * homelessness * disease * widespread hunger
Economic Impacts
* the government has to pay to rebuild everything * Loss of housing * Loss of industrial production * Loss of commerce * Loss of agriculture production * (plant crops and harvest) * Damage to infrastructure * Disordered markets & distribution * Interrupted transportation systems * Breakdown of communication
Means of Mitigating against it’s effects
There are many ways to reduce earthquake damage. Possible actions include: * Developing construction techniques that are seismic resistant. * Conducting a program to introduce improved construction techniques to the building industry and the general public. * Determining which sites are safe for construction through analysis of the soil type and geological structure. * Instituting incentives to remove unsafe buildings and buildings on unsafe sites or, more probably, to upgrade their level of safety. * Instituting incentives to encourage future development on safer sites and safer methods of construction through: * Land use controls (zoning). * Building Codes and standards and means of enforcing them. * Favourable taxation, loans, or subsidies to qualify buildings, methods and sites. * Land development incentives. * Reducing possible damage from secondary effects by: