Earthquakes are perhaps the most feared of all nature’s violence – they come suddenly with little warning. Unlike other natural hazards, such as flood and fire, little can be done to prepare for them. They range from minor vibrations in the earth, detectable only on delicate measuring instruments, to great upheavals tearing whole mountains apart.
Minor earth tremors can happen anywhere, but major quakes are confined to known earthquake belts where buildings could be planned to withstand them or to cause little damage if they do collapse – like traditional buildings in Japan. Modern cities rarely take this into account.
With constant monitoring by seismologists, major earthquakes can be predicted and some evacuation may be possible. Animals become very alert, tense and ready to run.
A detailed knowledge of local geology may indicate weak points along major fissures but the tremors and the waves of movement through the earth could extend to almost anywhere in an earthquake zone.
I have actually been through a few earthquakes and the experience is a little surreal. At first, it seems like a plane or large truck is passing through the vicinity. But after a few seconds one realizes that the shaking exceeds the momentary duration caused by either of these vehicles.
Of the three quakes I’ve experience, two were relatively minor and caused minimal damage but the experience was unnerving all the same.
The third occurred while I was in a high rise building – I don’t like being in high rise buildings (see my comment in Building Fires). But, I had read enough about earthquakes to know that I should stand in a doorway in case the building began to crumble. Somehow I managed to do this instinctively, without thinking about it, although I was not very happy.
The building did not crumble, thankfully, but this quake caused enough damage to force us to evacuate and meet in a nearby park for roll call.
Causes
Earthquakes are caused by the sudden release of tension built up in the Earth’s crust, as deep as 435 miles (700 km) below the surface – but only a rupture in the upper tens of kilometers is likely to produce movement affecting the surface. The shock wave for the 1964 Alaska earthquake, for instance, was at about 12 – 19 miles (20 – 30km) deep.
Earthquake belts lie along the edges of the semi-rigid plates that form the Earth’s crust. The deepest quakes occur along the ocean trenches, forming and destroying volcanic islands. The most violent tend to occur in areas where one plate is thrusting beneath another, as along the west coast of North America, where the San Andreas Fault is a particularly vulnerable zone.
A succession of preliminary tremors, known as fore shocks, often followed by a seismically quiet period, usually precede major quakes, which they can actually trigger. These initial tremors may not be noticeable.
Domestic Earthquake Precautions
Stay tuned to a local radio station for up-to-date reports and advice if you have a warning of a possible earthquake. Turn off gas, electricity and water if advised to do so.
Remove large and heavy objects from shelves, so they won’t fall on you. Put bottles, glass, china and other breakables in low cupboards. Shelves should have a lip or low barrier to stop things from slipping off. Cupboard doors should have positive fastening (i.e. locks that cannot work loose from vibrations), not just magnetic catches. Secure or remove suspended objects, such as large light fittings and hanging flower bowls.
Have the following ready:
You can choose to either create a kit manually or obtain a prepared kit that has all the necessary equipment – just in case you don’t want to miss anything. This professional kit company, created by First Responders themselves has been creating such kits for years. I encourage you to review their offerings, if for no other reason, to ensure your own kit has everything you and your family will need.
In A Car
Stop as quickly as you can – but stay in the car. It will offer some protection from falling objects. Crouch down below seat level and you will be further protected if anything falls on the car. When the tremors cease, keep a watch for any obstructions and hazards: broken cables, undermined roadways or bridges that could give way and collapse.
Indoors
If you are indoors when an earthquake strikes, stay there. Put out any fires. Stay away from glass, including mirrors, and especially from large windows.
- An inside corner of the house, or a well-supported interior doorway are good places to shelter.
- A lower floor or a cellar probably gives the best chance of survival – an upper floor could come crashing down with you on it. Make sure you are aware of any and all exits.
- Get beneath a table or other piece of substantial furniture which will give both protection and an air space.
- In a shop, keep away from large displays of goods which could come crashing down.
- In high-rise offices stay put. Never go into an elevator. Staircases may attract panicking people. Get under a desk.
Outdoors
If you are outdoors lie flat on the ground. Do NOT try to run. You will be thrown about and could be swallowed in a fissure.
- Keep away from tall buildings.
- Do not deliberately go underground or into a tunnel where you could be trapped by blockage or collapse.
- If you have managed to get to an open space do not move back into buildings because if minor tremors follow they could collapse any structure left unstable by the first quake.
- On a hillside it is safer to get to the top. Slopes are likely to landslide and there would be little chance of survival for anyone caught in the thousands of tons of earth and rock that could move with terrifying speed. People have been known to survive by rolling into a tight ball on the ground.
- Beaches – provided they are not below cliffs – are initially fairly safe. But since tidal waves often follow a quake, you should move off the beach to high, open ground as soon as the tremor has finished. Further tremors are unlikely to be as dangerous as a tsunami (see: How To Survive…Tsunami).
Aftermath Precautions
Rupture of sewage systems, contamination of water and the hazards of bodies trapped in the wreckage can all make the risk of disease as deadly as the earthquake itself. Bury all corpses, animal and human.
- Do NOT shelter in damaged buildings or ruins. Build a shelter from debris.
- Take special care over sanitation and personal hygiene. Filter and boil all water.
- Do not strike matches or lighters, or use electrical appliances, if there is any chance of a gas leak. The sparks could ignite any gas fumes, even if they are undetectable. (Note: Natural gas has no aroma – the “rotten egg” smell generally associated with Natural gas is artificially added to make leak detection easier).
- Check to ensure sewage services are intact before using bathrooms
- Open cupboards carefully, objects may tumble out.
- Be prepared for aftershocks.
Safety Precautions
KEEP AWAY FROM ANYTHING THAT MAY FALL ON YOU: trees in the open air, for they could be uprooted; buildings in towns, for – even if they are stable enough not to be demolished – pieces may come crashing down. Ideally evacuate to an open area but, if that is not possible – and you may have little time – it is safer to stay indoors.
In the street ruptured gas mains and power cables may add to the hazards. People going in and out are the ones most at risk from falling masonry on buildings.