EARTHQUAKES
One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible aftereffects.
Earthquakes strike suddenly, violently, and without warning at any
time of the day or night. If an earthquake occurs in a populated area,
it may cause many deaths and injuries and extensive property damage.
Although there are no guarantees of safety during an earthquake,
identifying potential hazards ahead of time and advance planning can
save lives and significantly reduce injuries and property damage.
Some 80 percent of all the planet's earthquakes occur along the rim
of the Pacific Ocean, called the "Ring of Fire" because of the
preponderance of volcanic activity there as well. Most earthquakes
occur at fault zones, where tectonic plates; giant rock slabs that make
up the Earth's upper layer; collide or slide against each other. These
impacts are usually gradual and unnoticeable on the surface. However,
immense stress can build up between plates. When this stress is
released quickly, it sends massive vibrations, called seismic waves,
often hundreds of miles through the rock and up to the surface. Other
quakes can occur far from faults zones when plates are stretched or
squeezed.
Scientists assign a magnitude rating to earthquakes based on the
strength and duration of their seismic waves. A quake measuring 3 to 5
would be considered minor or light; 5 to 7 is moderate to strong; 7 to
8 is major, and 8 or more is great.
On average, a magnitude 8 quake strikes somewhere every year and
some 10,000 people die worldwide annually in earthquakes. Collapsing
buildings claim by far the majority of lives, but the destruction is
often compounded by mud slides, fires, floods, or tsunamis. Smaller
temblors that usually occur in the days following a large earthquake
can complicate rescue efforts and cause further death and destruction.
Loss of life can be avoided through emergency planning, education,
and the construction of buildings that sway rather than break under the
stress of an earthquake.
How can I protect myself from an earthquake?
