LOS ANGELES EARTHQUAKE CONTINGENCY REPORT:
             Earthquakes are caused by the crust of the Earth not being rigid and immobile but being split up into various tectonic plate boundaries. For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth's surface move slowly over, under, and slide past each other. Sometimes the movement is gradual, and at other instances, the plates are locked together, unable to release the steadily accumulating energy. When the accumulated energy grows strong enough, the plates break free causing the ground to shake. Most earthquakes occur at the boundaries where the plates meet; however, some earthquakes occur in the middle of plates.
             Once the pressure is suddenly released into the surroundings from any point within the crust (referred to as the focus), the seismic waves that originate from the focus eventually reach the surface of the crust at the point referred to as the epicentre (area on surface directly above focus) where they may cause a jerking movement of the crust. Although the movement of the crust itself can be damaging, the secondary effects are considered to be far more devastating and result in a large number of fatalities. Ground shaking from earthquakes can collapse buildings and bridges; disrupt gas, electric, and phone service; and sometimes trigger landslides, avalanches, flash floods, fires, and destructive ocean waves (tsunamis). Buildings with foundations resting on unconsolidated landfill and other unstable soil, and trailers and homes not tied to their foundations are at risk because they can be shaken off their mountings during an earthquake. These secondary effects cause the greatest amount of damage especially in urban areas where there is a high population density as in the case of Los Angeles. The population of an urban centre such as Los Angeles are exposed to a greater number or potential hazards. If an earthquak...