- Education and Science
Understanding Earthquakes What to Do
How Earthquakes Work Discovery Channel
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In the last three months the earth seems to have woke up from a slumber and is shaking. Earthquakes in Haiti and now in Chile have caused massive damage... from tsunamis, fires, building and road destruction and collapse, debris falls, liquefaction, and power-outages earthquakes can be some of the most devastating disasters we as a people can face.
Earthquakes happen when two plates of the earth's crust form thrust-zones where one plate slides under the other. These massive continental plates build pressure over hundreds and thousands of years slowly pushing against one another. Once in a while there is a major thrust causing the earth's crust to explode in a massive slip... this is an earthquake. The seismic energy travels much like waves that ripple across a pond when a stone is thrown. The difference is that the medium that wave travels through is solid rock and is much more dense so the shaking of the top layer of the earth's crust is violent.
Earthquakes are measured in magnitude by geologists using a measurement called the Richter Scale. It is based on a scale of 10 times in magnitude where the scale is obtained by calculating the logarithm of the combined horizontal shaking and displacement from 0 on a seismometer's output on up and measures the amplitude of the quake... so a 5.0 on the Richter scale has a shaking amplitude 10 times larger than one that measures 4.0. Smaller deep earthquakes under the earth's crust can measure from 1.0 to about 4.0 and are not usually felt by the population. Larger quakes are felt as violent rolling or vertical thrusting. This violent shaking is what causes damage to property and loss of life.
Tsunamis are caused when earthquakes shake an area under the ocean causing massive water displacement. These swells can travel at up to 600 mph and can be devastating. Once a tsunami warning has been alerted it is time to head inland and to high ground. Do not linger, it is best to be away from the tsunami zone and not risk your life even if it seems you will be safe.
What to Know and How to be Prepared
At Work or Away From Home: Earthquakes can strike anytime and anywhere, the key is to always have a plan as to what you should do. If at work then it is a good idea to wait and see how bad the damage is. When it is safe make your way home. If you have children then be sure you teach them to stay at school until you can come and get them... make this your priority. Once home make sure that there are no gas leaks or water leaks within the house. Estimate the damage and begin to clean up anything that may pose a threat to your safety. Now take inventory of what you have that can help keep you safe and supplied for the next few days.
At Home Plan: If an earthquake strikes in the middle of the night it is best to keep a pair of shoes at the foot of the bed. This will help avoid broken glass and sharp objects that may fallen on the floor. To be safe head for a doorway and brace yourself against the side of the door jam, this will keep you against the structure of the building you are in. This is the strongest part of the home. If caught by a table then head under the table and cover your head and neck while getting into a fetal position on your knees. Stay in these areas until the shaking has ceased. If you are able it is best to head outside of the home to an open area away from structures or power lines. You will notice car alarms and sirens going off, streetlights and poles will be swaying, and if a pool of water is nearby it will be sloshing. Stay away from these places for they can be dangers. Again make sure that there are no gas leaks or water leaks within the house. Estimate the damage and begin to clean up anything that may pose a threat to your safety. Now take inventory of what you have that can help keep you safe and supplied for the next few days.
Supplies: Keep enough water for everyone in your home for a week. A family of four will need 7 gallons of water per person. Keep water purification tablets. There is water in the water heater of your home, in the toilet, this water can be used for cleaning. Keep canned and dried foods in a plastic container and high energy foods like peanut butter and crackers. Always have a first aid kit on hand that is fitted with a burn kit and sterile-strips for wound closures. Keep batteries, flashlights, and a battery operated radio at hand. These things can save your life. A good idea is to have solar lights instead of candles but having both would be a good idea.
Emergency Help: If the disaster is large enough emergency personnel will be on hand to help with things like water and food. There may be triage areas that are set up at local disaster shelters where you can get medical help. Don't count on them coming to get you and save you, they are always over taxed and usually need you to come to them.
The best thing one can do is to be prepared and always have a plan. You should come through the disaster just fine if you have prepared. You can then begin to help your neighbors and try to get life back to normal. Good luck and God Bless.