What would your first instincts be if there was an earthquake? Read on to learn more about earthquakes and how to survive one.
What causes earthquakes?
Earth’s crust is made up of approximately 20 small pieces of land. These pieces, called tectonic plates, hit or slide past each other. When this happens, pent up energy from inside the earth is suddenly released as seismic waves.
When these waves reach the earth’s surface, they cause cracks and shaking—sometimes violently. This phenomenon is an earthquake (also known as tremor or quake).
Tectonic plates are continuously moving. The movements, however, are slight and slow—at 1 to 10 cm a year—and mostly go unnoticed. Out of 1,000,000 detectable earthquakes each year worldwide, only about 100 of them cause real damage.
How much damage can earthquakes leave behind?
The stronger, rapid movements of tectonic plates are the ones to fear—some earthquakes are so intense that they can be felt 1,609 km away.
The damages are also catastrophic and deadly. From collapsed infrastructure (buildings, bridges, roads, power supplies, pipelines) and disrupted services (emergency and fire departments, telephone, Internet) to severe injuries and fatalities, including death of animals.
Sewer pipes can burst, gas lines can explode. Local businesses can be impacted for days or weeks; some may never reopen after a massive earthquake.
Even entire cities can be destroyed, depending on the magnitude of the earthquake. A magnitude of 3.0 or lower out of 10 (on a Richter scale) is usually imperceptible, but a 6.5 or higher causes significant damages over large areas.
Additionally, earthquakes are known to trigger secondary effects: tsunamis, landslides, fires, flash floods, avalanches, and diseases (respiratory tract infections, water-borne diseases).
The 2010 Haiti earthquake, for example, led to a cholera outbreak. By 2016, 770,000 people were sickened and more than 9,200 people had died from the epidemic.
In 2011, Japan suffered an earthquake with a magnitude of 9.0. It claimed nearly 16,000 lives.
The Chile earthquake in 1960 devastated and reduced the entire country to shambles. It also caused destruction in distant Pacific coastal areas, due to the tsunamis it generated. It had a magnitude of 9.5.
What do you need to know about earthquakes?
Here are some important points to note.
Seismic zones (are you in one?)
A seismic zone is a region in which the seismic activity rate is fairly consistent. This may mean that seismic activity is incredibly rare, or that it is extremely common.
Some use the term ‘seismic zone’ to refer to an area with an increased risk of seismic activity. Others prefer ‘seismic hazard zones’ when discussing areas prone to frequent seismic activity.
Can they be predicted? Prepared for?
Earthquakes strike without warning, at any area and time of the year, day or night. While it is not always possible to predict these forces of nature, we can be prepared for them.
Aftershocks and foreshocks
Aftershocks following earthquakes can occur after mere hours, or happen days, weeks, months or even years later.
They are not to be taken lightly, as they can cause further damage to weakened buildings. These secondary effects of earthquakes account for 40% of deaths and economic losses.
Scarier still is that some earthquakes are actually foreshocks, and a larger earthquake might ensue.
Types of buildings that are prone to risk
Building codes are intended to ensure that structures are safe. Seismic provisions in building codes go one step further. They ensure the structures can withstand seismic forces during earthquakes, thereby reducing losses and saving lives.
Buildings that adopt outdated building codes in terms of seismic provisions, or lack such provisions altogether, are a major risk during earthquakes. This is especially so for buildings in earthquake prone regions.
Older structures are potentially at risk. These buildings may not be protected against earthquakes, as their code requirements are those that were in effect when these structures were designed and constructed.
Typically, building foundations that rest on unstable soil are at risk of collapsing during earthquakes. As for houses that are not secured to their foundations, they risk being shaken off their foundations during tremors.
Do human activities cause them?
Yes, human activities and anthropogenic projects can cause earthquakes.
- Mining: Removing rocks from the earth causes instability, leading to sudden collapses that trigger earthquakes.
- Dam building: Scientists believe that the 2008 China earthquake was triggered by the weight of water (320 million tonnes) that had been collected in a reservoir over a well-known fault line. The resulting earthquake had a magnitude of 7.9.
- Fracking: This process used to extract oil and gas from the ground can induce seismic activity. Fracking, especially the underground, high-pressured wastewater injection after fracking, triggers earthquakes. An example is the 2016 Oklahoma earthquake which had a magnitude of 5.8.
How to plan for an earthquake?
Here is how you can plan for an earthquake.
Create an earthquake safety plan
A safety plan will keep your family, including your pet(s), safe when an earthquake strikes. It entails deciding beforehand what to do, where to meet if separated, and how to communicate.
It is useful to identify a relative or friend who lives away from your area that your family members can check in with during the emergency.
Secure your home
It is advisable to identify and fix earthquake hazards in your home. Weak spots can be retrofitted—this involves strengthening the house’s foundation to better withstand shaking.
Heavy furniture and shelves can be fastened to walls or bolted down—this prevents injuries caused by large items falling over or being crushed beneath them during an earthquake.
Loose objects, especially breakable ones, can be secured properly—this minimises harm by way of keeping spaces where people might sit or sleep safe.
Electrical wiring defects and gas connection leaks must be repaired, as they are fire risks if an earthquake occurs.
Pick safe places
Identify the safe places, both indoors (in each room of your house) and around your house, for shelter should an earthquake happen.
Practice the drop-cover-hold techniques
Injuries and deaths during an earthquake mostly occur when people try to escape a building. It is impossible to walk or run safely while the ground is shaking and things are falling all around you.
The recommended survival tip is ‘drop-cover-hold’. Practice these techniques often with your family members.
In the first moments of an earthquake, drop to your knees. Once on the floor, find cover such as a sturdy table. Crawl over quickly and get under it for shelter. If the shaking starts moving the table around, hold on to a leg and stay under your cover.
If you cannot find cover, the best is still to drop where you are—resist the urge to escape outside. You could even drop beside a bed, sofa or other solid furniture, and keep yourself small.
Here are some survival tips for children during an earthquake.
- Inside or outside a house or building
- Teach children the drop-cover-hold techniques and not to panic during the crisis—here is where practising is important.
- If they drop next to a wall indoors, teach them to avoid all glass windows and mirrors.
- If they are outside when tremors are felt, teach them to:
- stay away from buildings, trees and power supplies as these may collapse.
- drop in an open area and crouch until the shaking stops.
- Exiting a house or building when escaping is necessary
- Teach children the safest escape path, leading from their sleeping location to the exit. This path should be free from the possibility of falling furniture or breaking glass.
Keep a disaster supply kit ready (flashlight, first aid, water, etc.)
Prepare supplies for your family and pet(s) to get through at least the first three days after an earthquake. This 72-hour duration is how long it can take for emergency services to reach you to provide aid.
Other useful supplies that can be added are food, batteries, a radio, certain tools and spare clothing. It is also a good idea to equip your car with a disaster supply kit.
What to do during an earthquake?
Act fast to protect yourself when an earthquake strikes.
Go into survival mode
Execute your safety plan and the drop-cover-hold techniques as quickly—and calmly—as you can. Get to your safe places or drop where you are, seek cover and protect your head, neck, face and eyes.
If you are in a moving vehicle, stop the vehicle in an open area—away from buildings, trees, power supplies and bridges that may collapse—and stay in it.
Be mindful of gas leaks
Lighting a lighter or match to illuminate your surroundings must be completely avoided, just in case there is a broken gas line.
Stay alert if you are trapped
Keeping calm and alert will help you immensely if you are trapped under the debris of an earthquake.
Shouting for help may cause you to inhale dangerous amounts of dust. This, in turn, might make you choke or suffocate. Thus, it is better to tap on a wall or pipe to enable rescuers to find you in the rubble. Shout only as a last resort.
Cover your mouth with a piece of clothing or your palm to prevent breathing in dust. Stay still as well, so that as little dust as possible is disturbed or kicked up.
What to do after an earthquake?
After an earthquake, remember these points.
Avoid using elevators
After the tremors stop, choose the stairs over elevators to leave any building. Be mindful of broken glass, debris and other hazards on the ground and around you as you leave.
Check for injuries
Check if you or anyone else is hurt, and provide first aid or request medical help for those who are injured.
Check for damages and structural hazards
Check electric, gas and water lines for damage—open all windows and doors if you smell a gas leak. This circumvents a potential explosion or fire risk. Then, leave immediately and report the matter to the authorities.
Look for damage and cracks to the roof or ceiling, walls and foundation of your house. If a building or area is badly damaged, avoid going near it.
Be vigilant for aftershocks
Avoid the beach if there is one nearby, in case of aftershocks and consequent tsunamis. Move to higher ground immediately.
Listen to the radio for public safety updates and instructions.
The best proactive approach to survive an earthquake involves adequate planning and proper execution. It also helps to base your preparations on informed decisions and common sense.
You can minimise the risk of injuries and deaths caused by earthquakes. This is possible through adopting the right safety measures and knowing the ‘dos and don’ts’ during and after an earthquake.
Most importantly, remember the mantra: drop-cover-hold. Execute the above survival tips during an earthquake as calmly as possible. Keeping calm saves lives!