Earthquakes are not a frequent occurrence, but when they do strike, the magnitude of damage they cause is insurmountable. The recent earthquake that struck Nepal and North Indian states is nature’s way of reminding us that man has little control over natural calamities. While we are at nature’s mercy and try to keep an optimistic outlook, what we can do, is be better prepared and better informed. Being prepared in advance is critical to minimize damages and loss. Consider these earthquake safety tips:
What to do during an earthquake
➢ Drop, cover, and hold on! Move only a few steps to a nearby safe place. Most injured persons in earthquakes move more than five feet during the shaking. It is very dangerous to try to leave a building during an earthquake because objects can fall on you. Many fatalities occur when people run outside buildings, only to be killed by falling debris from collapsing walls.
➢ If you are in bed, hold on and stay there, protecting your head with a pillow. You are less likely to be injured staying where you are. Broken glass on the floor has caused injury to those who have rolled to the floor or tried to get to doorways.
➢ If you are outdoors, find a clear spot away from buildings, trees, streetlights, and power lines. Drop to the ground and stay there until the shaking stops. Injuries can occur from falling trees, street-lights and power lines, or building debris.
➢ If you are in a vehicle, pull over to a clear location, stop and stay there with your seatbelt fastened until the shaking has stopped. Trees, power lines, poles, street signs, and other overhead items may fall during earthquakes. Stopping will help reduce your risk, and a hard-topped vehicle will help protect you from flying or falling objects. Once the shaking has stopped, proceed with caution. Avoid bridges or ramps that might have been damaged by the quake.
➢ Stay away from windows. Windows can shatter with such force that you can be injured several feet away.
➢ In a high-rise building, expect the fire alarms and sprinklers to go off during a quake. Earthquakes frequently cause fire alarm and fire sprinkler systems to go off even if there is no fire. Check for, and extinguish small fires, and, if exiting, use the stairs.
➢ If you are in a coastal area, move to higher ground. Tsunamis are often created by earthquakes.
➢ If you are in a mountainous area or near unstable slopes or cliffs, be alert for falling rocks and other debris that could be loosened by the earthquake. Landslides commonly happen after earthquakes.
What to do after an earthquake
➢ Check yourself for injuries. Often people tend to others without checking their own injuries. You will be better able to care for others if you are not injured or if you have received first aid for your injuries.
➢ Protect yourself from further danger by putting on long pants, a long-sleeved shirt, sturdy shoes, and work gloves. This will protect you from further injury by broken objects.
➢ After you have taken care of yourself, help injured or trapped persons. If you have it in your area, base emergency, then give first aid when appropriate. Don’t try to move seriously injured people unless they are in immediate danger of further injury.
➢ Look for and extinguish small fires. Eliminate fire hazards. Putting out small fires quickly, using available resources, will prevent them from spreading. Fire is the most common hazard following earthquakes. Fires followed the San Francisco earthquake of 1906 for three days, creating more damage than the earthquake.
➢ Leave the gas on at the main valve, unless you smell gas or think its leaking. It may be weeks or months before professionals can turn gas back on using the correct procedures. Explosions have caused injury and death when homeowners have improperly turned their gas back on by themselves.
➢ Clean up spilled medicines, bleaches, gasoline, or other flammable liquids immediately. Avoid the hazard of a chemical emergency.
➢ Open closet and cabinet doors cautiously. Contents may have shifted during the shaking of an earthquake and could fall, creating further damage or injury.
➢ Inspect your home for damage. Get everyone out if your home is unsafe. Aftershocks following earthquakes can cause further damage to unstable buildings. If your home has experienced damage, get out before aftershocks happen.
➢ Help neighbours who may require special assistance. Elderly people and people with disabilities may require additional assistance. People who care for them or who have large families may need additional assistance in emergency situations.
➢ Listen to a portable, battery-operated radio (or television) for updated emergency information and instructions. If the electricity is out, this may be your main source of information. Local radio and local officials provide the most appropriate advice for your particular situation.
➢ Expect aftershocks. Each time you feel one, drop, cover, and hold on! Aftershocks frequently occur minutes, days, weeks, and even months following an earthquake.
➢ Watch out for fallen power lines or broken gas lines, and stay out of damaged areas. Hazards caused by earthquakes are often difficult to see, and you could be easily injured.
➢ Stay out of damaged buildings. If you are away from home, return only when authorities say it is safe. Damaged buildings may be destroyed by aftershocks following the main quake.
➢ Use battery-powered lanterns or flashlights to inspect your home. Kerosene lanterns, torches, candles, and matches may tip over or ignite flammables inside.
➢ Avoid smoking inside buildings. Smoking in confined areas can cause fires.
➢ When entering buildings, use extreme caution. Building damage may have occurred where one least expect it. Carefully watch every step you take. Examine walls, floor, doors, staircases, and windows to make sure that the building is not in danger of collapsing.
➢ Watch for loose plaster, dry wall, and ceilings that could fall.
➢ Use the telephone only to report life-threatening emergencies. Telephone lines are frequently overwhelmed in disaster situations. They need to be clear for emergency calls to get through.
Being Proactive: What all can you do before an earthquake
➢ Know your risk. Research and find out if you live near an active fault line, and whether or not the ground around you is more susceptible to the effects of an earthquake.
➢ Retrofit and reinforce your house. If you’re in a high risk area, take steps to reinforce your house. Bolt your house to the foundation and reinforce support beams as needed. Secure any furniture such as bookshelves and cabinets to the walls to minimize risk of falling over during a quake. (Secure cabinet doors to help keep dishes and other contents from falling out.)
➢ Create a disaster plan to protect yourself and your family. Earthquake preparedness can help reduce anxiety and minimize injury. Know where to take cover in your house and how to communicate with other family members after the earthquake if you’re not together. Designate a safe place to meet outside of the house after the shaking stops. Get to know the people in your community better by getting actively involved in community disaster training.
➢ Put together an emergency kit. Your kit should include non-perishable food, water, first aid supplies, flashlights, camping supplies (stove, battery-powered lantern, etc.), extra batteries, blankets, and any personal items you may need (medications, toiletries, clothing). If you have pets, make sure you have adequate supplies for them as well. Plan for a week’s worth of supplies for each person. You’ll need at least four gallons of drinking water per person for a week.
How to protect your property
➢ Brace or anchor high or top-heavy objects, secure items that might fall (televisions, books, computers, etc.) During an earthquake, these items can fall over, causing damage or injury.
➢ Move large or heavy objects and fragile items (bottled food, glass, china, etc.) to lower shelves. There will be less damage and less chance of injury if these items are on lower shelves.
➢ Store weed killers, pesticides, and flammable products securely in closed cabinets with latches, on bottom shelves. Chemical products will be less likely to create hazardous situations from lower, confined locations.
➢ Hang heavy items, such as pictures and mirrors, away from beds, couches, and anywhere people sit. Earthquakes can knock things off walls, causing damage or injury.
➢ Brace overhead light fixtures. During earthquakes, overhead light fixtures are the most common items to fall, causing damage or injury.
➢ Strap the water heater to wall studs. The water heater may be your best source of drinkable water following an earthquake. Protect it from damage and leaks.
➢ Bolt down any gas appliances. After an earthquake, broken gas lines frequently create fire hazards.
➢ Install flexible pipe fittings to avoid gas or water leaks. Flexible fittings will be less likely to break.
➢ Consider having your building evaluated by a professional structural design engineer. Ask about home repair and strengthening tips for exterior features, such as porches, front and back decks, sliding glass doors, canopies, carports, and garage doors. Learn about additional ways you can protect your home. A professional can give you advice on how to reduce potential damage.
Our hearts go out to everyone who is in the midst of this devastating natural disaster. We often underestimate the importance of being prepared because we forget that tragedy strikes when we least expect it to, leaving our world topsy-turvy. Each of us hopes that no one is ever caught in the middle of such a situation, but if we do, we hope that these pointers will save many lives.
An earthquake (or quakes, tremors) is the shaking of the surface of the earth, caused by ￼￼the sudden movement in the Tectonic Plates. They can be extremely violent or cannot be felt by anyone.
Earthquakes are usually quite brief, but may repeat. They are the result of a sudden release of energy in the Tectonic Plates. This creates seismic waves, which are waves of energy that travel through the Earth. The study of earthquakes is called seismology.Seismology studies the frequency, type and size of earthquakes over a period of time.
There are large earthquakes and small earthquakes. Large earthquakes can take down buildings and cause death and injury. Earthquakes are measured using observations from seismometers. The magnitude of an earthquake, and the intensity of shaking, is usually reported on the Richter scale.The Richter Scale was invented by Charles Francis Richter in 1935. On the scale, 3 or less is scarcely noticeable, and magnitude 5 (or more) causes damage over a wide area.
An earthquake under the ocean can cause a tsunami. This can cause just as much death and destruction as the earthquake itself. Landslides can happen, too. Earthquakes are part of the Earth's rock cycle. The impact can be measured by a seismometer. It detects the vibrations caused by an earthquake. It puts these movement on a seismograph. The strength, or magnitude, of an earthquake is measured using the Richter scale. The Richter scale is numbered 0-9.
Scientists have never predicted a major earthquake before. They do know where earthquakes may occur, such as close to the fault lines.
When earthquakes occur the Richter Scale draws how big it is and how big its getting.
Mitigation Strategies- If you are indoors:-
- Take cover under a table or bench. If there is no table or desk, sit against a wall away from things that might fall on you and away from windows, bookcases or tall, heavy furniture.
- Wait in your safety spot until the shaking stops and then check to see if you are hurt. Check others around you too. Move carefully and look out for fallen things.
- There may be aftershocks or smaller earthquakes quite soon after. So be prepared.
- If you want to leave the building after the shaking stops , use the stairs, never use lifts.
If you are outdoors :-
- Stay outside and move away from buildings, trees, lights and power lines. Crouch down and cover your head!
History[change | change source]
Earthquakes sometimes hit cities and kill hundreds of thousands of people. Most earthquakes happen along the Pacific Ring of Fire but the biggest ones mostly happen in other places. Tectonically active places are places where earthquakes or volcanic eruptions are frequent.
The ancient Chinese used a device that looked like a jar with dragons on the top surrounded by frogs with their mouths open. When an earthquake occurred, a ball in each dragon's mouth would drop out of the dragon's mouth into the frog's. The position of the frog which received a ball indicated the direction of the earthquake. This was one of the first tools to help figure out where an earthquake originated from.
Causes of an earthquake[change | change source]
Main article: plate tectonics
Earthquakes are caused by tectonic movements in the Earth's crust. The main cause is that when tectonic plates , one rides over the other, causing orogeny collide (mountain building), earthquakes.
The boundaries between moving plates form the largest fault surfaces on Earth. When they stick, relative motion between the plates leads to increasing stress. This continues until the stress rises and breaks, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy as shock waves. Such faults are San Andreas fault in San Francisco , Rift valley in Africa etc
Earthquake fault types[change | change source]
There are three main types of geological fault that may cause an earthquake: normal, reverse (thrust) and strike-slip. Normal faults occur mainly in areas where the crust is being extended. Reverse faults occur in areas where the crust is being shortened. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other.
Earthquake clusters[change | change source]
Most earthquakes form part of a sequence, related to each other in terms of location and time. Most earthquake clusters consist of small tremors which cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.
A foreshock is an earthquake that occurs before a larger earthquake, called the mainshock.
An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. Aftershocks are formed as the crust adjusts to the effects of the main shock.
Earthquake swarms are sequences of earthquakes striking in a specific area within a short period of time. They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notably higher magnitudes than the other. An example of an earthquake swarm is the 2004 activity at Yellowstone National Park.
Sometimes a series of earthquakes occur in a sort of earthquake storm, where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern occurred in the North Anatolian fault in Turkey in the 20th century.
Tsunami[change | change source]
Main article: Tsunami
Tsunami or a chain of fast moving waves in the ocean caused by powerful earthquakes is a very serious challenge for people's safety and for earthquake engineering. Those waves can inundate coastal areas, destroy houses and even swipe away whole towns. This is a danger for the whole mankind.
Unfortunately, tsunamis can not be prevented. However, there are warning systems which may warn the population before the big waves reach the land to let them enough time to rush to safety.
Earthquake-proofing[change | change source]
Main article: Earthquake engineering
Some places, such as Japan or California, have many earthquakes and many inhabitants. There, it is good practice to construct houses and other buildings which will resist collapse in an earthquake. This is called seismic design or "earthquake-proofing".
Earthquake-proof buildings are constructed to withstand the destructive force of an earthquake. This depends upon its type of construction, shape, mass distribution, and rigidity. Different combinations are used. Square, rectangular, and shell-shaped buildings can withstand earthquakes better than skyscrapers. To reduce stress, a building's ground floor can be supported by extremely rigid, hollow columns, while the rest of the building is supported by flexible columns inside the hollow columns. Another method is to use rollers or rubber pads to separate the base columns from the ground, allowing the columns to shake parallel to each other during an earthquake.
To help prevent a roof from collapsing, builders make the roof out of light-weight materials. Outdoor walls are made with stronger and more reinforced materials such as steel or reinforced concrete. During an earthquake flexible windows may help hold the windows together so they don’t break.
Sources[change | change source]
- ↑Earth Science. Austin, Texas 78746-6487: Holt, Rinehart Winston. 2001. ISBN 0-03-055667-8.
- ↑ 2.02.1"What are aftershocks, foreshocks, and earthquake clusters?".
- ↑"Repeating earthquakes". United States Geological Survey. January 29, 2009. Retrieved May 11, 2009.
- ↑"Earthquake swarms at Yellowstone". USGS. Retrieved 2008-09-15.
- ↑Amos Nur (2000). "Poseidon’s horses: plate tectonics and earthquake storms in the late [Bronze Age Aegean and Eastern Mediterranean"]. Journal of Archaeological Science27: 43–63. doi:10.1006/jasc.1999.0431. ISSN 0305-4403. http://water.stanford.edu/nur/EndBronzeage.pdf.
- ↑"Earthquake storms". Horizon (BBCtv series). 9pm 1 April 2003. Retrieved 2007-05-02.
- ↑USGS Poster of the Near the East Coast of Honshu, Japan Earthquake of 11 March 2011 - Magnitude 8.9
- ↑Pacific Tsunamy Warning Center