This text wants to tell us about the two strong earthquakes that shook Greece some months ago. The strength of each earthquake was 6.5 Richter scale (in the first earthquake) and 6.4 Richter scale (in the second earthquake).Earth scientists believe that most earthquakes are caused by slow movements inside the Earth that push against the Earth's brittle, relatively thin outer layer, causing the rocks to break suddenly. This outer layer is fragmented into a number of pieces, called plates. Most earthquakes occur at the boundaries of these plates.
In Washington State, the small Juan de Fuca plate off the coast of Washington, Oregon, and northern California is slowly moving eastward beneath a much larger plate that includes both the North American continent the land beneath part of the Atlantic Ocean. Plate motions in the Pacific Northwest result in shallow earthquakes widely distributed over Washington and deep earthquakes in the western parts of Washington and Oregon. The movement of the Juan de Fuca plate beneath the North America plate is in many respects similar to the movements of plates in South America, Mexico, Japan, and Alaska, where the world's largest earthquakes occur.
How can you put a limit on learning more? The next section may contain that one little bit of wisdom that changes everything.
Earthquakes are usually happened when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don't just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving.
After a while, the rocks break because of all the pressure that's built up. When the rocks break, the earthquake occurs. During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again. The spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus (on top of the ground) is called the epicenter of the earthquake.
Earthquake-like seismic waves can also be happened by explosions underground. These explosions may be set off to break rock while making tunnels for roads, railroads, subways, or mines. These explosions, however, don't cause very strong seismic waves. You may not even feel them. Sometimes seismic waves occur when the roof or walls of a mine collapse. These can sometimes be felt by people near the mine. The largest underground explosions, from tests of nuclear warheads (bombs), can create seismic waves very much like large earthquakes. This fact has been exploited as a means to enforce the global nuclear test ban, because no nuclear warhead can be detonated on earth without producing such seismic waves.
Earthquake Preparedness
The solution of the disaster is if the earthquake is happening, we must run as fast as possible and get out of the buildings. If someone lives in an apartment, hotel, or the other buildings, he or she must search for the emergency stairs. It will not help you if you used the lift, because it can kill yourself, because maybe the rope that holds the lift will be cut.
If someone lives in a house, he must get out as fast as he/she can. But if you're stuck, you must cover under a table, or something that you think strong enough to cover yourself from the roof to hit you directly.
Preparing before an earthquake comes, we should make tight some weak things (such as a cupboard). Then we must check the stability of the hanging things which it can be fall when the earthquake happens. If you want to build a house, make sure that the foundation is strong and you should know the emergency stairs when you're in a building. Actually, we need a geography information system to support us in facing earthquake disaster.
Knowing enough about Earthquake to make solid, informed choices cuts down on the fear factor. If you apply what you've just learned about Earthquake, you should have nothing to worry about.
Written by : Valla Mareta Prameshwari
