Earthquakes can happen anytime, anywhere. They occur without notice and although they last only seconds, their effects range from unnoticeable to mildly disturbing to devastating. In worst-case scenarios, buildings collapse, people are displaced, and lives are lost.
What Causes an Earthquake?
The earth is in constant motion. Its surface is a patchwork of tectonic plates that slowly move around, sometimes colliding with, pulling apart from or rubbing against each other. Their movements can cause major geological events, including earthquakes.
Most earthquakes occur along fault lines, cracks in the earth’s surface where rocks on either side can move past each other. As these rocks move, they sometimes lock together. When they do break free, this leads to a release of pressure—and an earthquake.
Seismologists, scientists who study earthquakes, measure their size in terms of energy released. Using the moment magnitude scale, which replaced the Richter scale in the 1970s, scientists can rank earthquakes from one to nine. Generally, earthquakes of 3.5 or less cannot be felt, whereas earthquakes of 7.0 or greater can cause widespread destruction.
How Common Are Earthquakes?
Earthquakes of various magnitudes are a daily occurrence all around the world. Many occur in uninhabited regions or are so small that they aren’t felt by humans. Still, every year we do have our share of major earthquakes.
In April of 2016, for example, two earthquakes—a 6.0 and a 7.0—hit Japan, killing at least 50 people and injuring about 3,000 others. One day after Japan’s 7.0 earthquake, a 7.8 earthquake hit Ecuador, causing widespread damage and killing at least 673 people. And in August of 2016, a 6.2 earthquake struck central Italy, devastating villages and taking close to 300 lives.
Can Earthquakes Be Predicted?
Scientists can predict where earthquakes are most likely to occur, but they cannot predict when. That’s because the tectonic movements that lead to earthquakes originate from geological processes at work far below the earth’s surface, making them difficult to study.
Rather than attempt predictions, organizations such as the United States Geological Survey focus on mitigating earthquake hazards through earthquake-resistant construction, awareness, and preparedness. That’s what you can do, too.
What to Do During an Earthquake
Earthquakes can occur anywhere—while you’re at home, visiting friends and family, or on vacation—so it pays to be prepared and know how to respond. If you live in a high-seismic area, it’s crucial to evaluate your home and take steps to make it more earthquake-resistant. Most earthquake casualties are caused by collapsed walls, falling objects, and shattered glass—not ground movements—and can be prevented.
The Federal Emergency Management Agency (FEMA) offers these recommendations to help you prepare for and respond to an earthquake:
If you’re inside a structure:
- Remain in the building and immediately “Drop, Cover, and Hold On.” This routine is recommended by emergency rescue teams. First, drop down to your hands and knees so that you’re less likely to be knocked down. Cover your head and neck with one arm and hand. Then, crawl under a sturdy desk or table to take shelter and hold on. If you can’t take shelter under a piece of furniture, cover your head and neck with both arms and hands.
- Stay away from anything that could fall, such as light fixtures, mirrors, and bookcases.
- Avoid doorways. Contrary to common belief, doorways in modern homes offer no more protection than any other part of the house, and swinging doors may actually present a hazard.
- Remain inside until the shaking is over.
- If you’re inside a house or building that begins to collapse, evacuate the structure as soon as possible through the nearest exit after the shaking has stopped.
- Take the stairs, not the elevator, as the elevator could become stuck or fall, both of which could lead to serious injury or death.
- If you become trapped in a collapsing structure, follow the “Drop, Cover, and Hold On” routine.
If you’re driving:
- Pull over to the side of the road, at a location that is clear of buildings, trees, overpasses and utility wires.
- Stay in your car until the quake ends.
- Do not attempt to drive across bridges or overpasses that have been damaged, either during or after the quake.
- Avoid downed power lines. If a power line should fall on your car, remain in the car until a trained professional can remove it.
If you’re outside:
- Move to an open area away from buildings, trees, streetlights and utility wires.
- If you cannot move to an open area (e.g., you’re in the middle of a city), do your best to avoid flying debris. Duck into a building if necessary, but first make sure it does not seem on the verge of collapse.
How to Reinforce Your Home’s Structure
All structures are vulnerable to the effects of an earthquake, but you can take steps to strengthen your home in advance. Work with a licensed engineer or contractor to have your home evaluated and earthquake-proofed, if it isn’t already. These types of structures are especially prone to damage in an earthquake:
- Garages and homes with living space over a first-floor garage. Garages typically lack interior walls and can collapse under the effects of an earthquake. If your garage supports second-floor living space, your entire home is at risk. Have the garage walls strengthened by adding bracing, such as shear walls or steel frames.
- Homes built before 1985, especially those built pre-WWII. Most modern homes conform to stricter building codes and can better resist the force of an earthquake. However, older homes may not be bolted to their foundations, and their crawl spaces may not be reinforced, which can cause their foundations to buckle and collapse under the force of an earthquake. Work with an engineer to stabilize your home’s foundation if it is weak, and install plywood sheathing to shore up crawl spaces.
- Mobile homes. Mobile homes are lighter in weight and can shift off their supports if they are not secured to the ground. To retrofit a mobile home, install a conventional foundation or certified Earthquake Restraint Bracing System (ERBS).
- Chimneys. These are often damaged during earthquakes. Have yours checked for loose masonry and repair as necessary. Retrofit options include replacing the bricks in the upper part of the chimney with metal, as well as installing a diagonal steel brace that secures the chimney to the framing of the roof.
How to Prepare Your Home’s Interior
To earthquake-proof the interior of your home:
- Bolt or brace water heaters, gas appliances, bookcases and wall units to wall studs.
- Secure upper kitchen cabinets to the wall studs and use earthquake-proof latches to keep cabinet doors from flying open.
- Anchor or brace overhead fixtures such as ceiling fans and hanging lights.
- Hang pictures, mirrors and other heavy objects away from beds and sofas.
- Ensure that gas appliances have flexible connections. Traditional steel piping can break during an earthquake, causing gas to leak.
- Move flammable liquids to an outside storage area to prevent hazardous leaks or explosions in your home.
How to Safeguard Yourself and Your Family
Every member of your family should know how to respond when an earthquake occurs. Identify the safest areas to take cover and hold periodic drills to practice the “Drop, Cover, and Hold On” routine, or one of its modified forms for those with disabilities.
Because earthquakes can cause damage to your home’s electricity, gas, and water systems, make sure that everyone in your household knows how to turn them off. You may need to do so after a quake has ended to prevent further damage, such as an electrical fire or gas explosion.
Prepare an emergency preparedness kit that includes the supplies that you would need to survive without assistance for at least three days, including:
- Non-perishable food for family members and pets
- Camp stove for cooking purposes
- One gallon of water, per person or pet, per day
- Flashlight with spare batteries
- Battery-powered or crank radio
- Spare batteries
- Medications and personal hygiene supplies
- Toilet paper
- Fire extinguisher
- First aid kit
Also consider setting aside a supply of cash in case ATMs and banks are not operating, and plan how family members will communicate. Put together a list of important phone numbers and email addresses, including out-of-state contacts, for all family members to carry with them at all times.
These measures can help you mitigate the effects of a quake and respond in an effective manner. But remember that even with the most thorough preparation, an earthquake can cause extensive and costly damage to your home.
Should You Purchase Earthquake Insurance?
If you live in an earthquake zone, an investment in earthquake insurance may be worthwhile. Standard homeowners insurance does not cover damage caused by earthquakes, but it may be available as an endorsement or separate policy.
Earthquake coverage typically pays for repairs to your home and attached structures, your personal belongings, and additional living expenses—should you need to move out while repairs are being made. Optional coverage may be available for building code upgrades, land restoration, and emergency repairs.
READ MORE: Can You Afford to Replace Your Home?