Earthquake Info

Earthquakes strike suddenly, violently and without warning. Identifying potential hazards ahead of time and advance planning can reduce the dangers of serious injury or loss of life from an earthquake.

Information compiled from the Federal Emegency Management Agency.

Earthquake Facts

What is an Earthquake?

An earthquake is a sudden, rapid shaking of the Earth caused by the breaking and shifting of rock beneath the Earth's surface. This shaking can cause buildings and bridges to collapse; disrupt gas, electric, and phone service; and sometimes trigger landslides, avalanches, flash floods, fires, and huge, destructive ocean waves (tsunamis). Buildings with foundations resting on unconsolidated landfill, old waterways, or other unstable soil are most at risk.

Buildings or trailers and manufactured homes not tied to a reinforced foundation anchored to the ground are also at risk since they can be shaken off their mountings during an earthquake. Earthquakes can occur at any time of year.

Earthquakes occur most frequently west of the Rocky Mountains, although historically the most violent earthquakes have occurred in the central United States. All 50 states and all U.S. territories are vulnerable to earthquakes. Forty-one states or territories are at moderate to high risk.

In 1886 an earthquake struck the downtown Charleston area. Although no measurement scales were available at that time to measure the size of the earthquake, it is believed that the earthquake was considerably strong. Current seismology reports indicate that the Charleston area experiences small earthquakes on a regular basis

Quick Emergency Info
  1. The best protection during an earthquake is to get under heavy furniture such as a desk, table, or bench.
  2. The greatest danger exists directly outside buildings, at exits, and alongside exterior walls. Many of the 120 fatalities from the 1933 Long Beach earthquake occurred when people ran outside of buildings only to be killed by falling debris from collapsing walls.
  3. Ground movement during an earthquake is seldom the direct cause of death or injury. Most earthquake-related casualties result from collapsing walls, flying glass, and falling objects.
Poll Worker Handbook
Ways to Prepare
Check for hazards in the home: *Handles traffic violations and more
  • Fasten shelves securely to walls.
  • Place large or heavy objects on lower shelves.
  • Store breakable items such as bottled foods, glass, and china in low, closed cabinets with latches.
  • Hang heavy items such as pictures and mirrors away from beds, couches, and anywhere people sit.
  • Brace overhead light fixtures.
  • Repair defective electrical wiring and leaky gas connections. These are potential fire risks.
  • Secure a water heater by strapping it to the wall studs and bolting it to the floor.
  • Repair any deep cracks in ceilings or foundations. Get expert advice if there are signs of structural defects.
  • Store weed killers, pesticides, and flammable products securely in closed cabinets with latches and on bottom shelves.
Have disaster supplies on hand:
  • Flashlight and extra batteries
  • Portable, battery-operated radio and extra batteries
  • First aid kit and manual
  • Emergency food and water
  • Nonelectric can opener
  • Essential medicines
  • Cash and credit cards
  • Sturdy shoes
  • Also see the complete Emergency Supplies Kit listing
Identify safe places in each room: *Handles traffic violations and more
  • Under sturdy furniture such as a heavy desk or table.
  • Against an inside wall.
  • Away from where glass could shatter - around windows, mirrors, pictures, or where bookcases or other heavy furniture could fall over.
Locate safe places outdoors: *Handles traffic violations and more
  • In the open, away from buildings, trees, telephone and electrical lines, overpasses, or elevated expressways.
Mitigation *Handles traffic violations and more

Mitigation includes any activities that prevent an emergency, reduce the chance of an emergency happening, or lessen the damaging effects of unavoidable emergencies. Investing in preventive mitigation steps now such as repairing deep plaster cracks in ceilings and foundations, anchoring overhead lighting fixtures to the ceiling and following local seismic building standards, will help reduce the impact of earthquakes in the future.

For more information on mitigation, contact the Emergency Management Department.

Develop an emergency communication plan *Handles traffic violations and more

In case family members are separated from one another during an earthquake (a real possibility during the day when adults are at work and children are at school), develop a plan for reuniting after the disaster.

Ask an out-of-state relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone in the family knows the name, address and phone number of the contact person.

  • Make sure all family members know how to respond after an earthquake.
  • Teach all family members how and when to turn off gas, electricity, and water.
  • Teach children how and when to call 9-1-1 and which radio station to tune to for emergency information.
Poll Worker Handbook
When an Earthquake Strikes
If indoors: *Handles traffic violations and more
  • Take cover under a piece of heavy furniture or against an inside wall and hold on.
  • Stay inside.
  • The most dangerous thing to do during the shaking of an earthquake is to try to leave the building because objects can fall on you.
If outdoors:
  • Move into the open, away from buildings, street lights, and utility wires.
  • Once in the open, stay there until the shaking stops.
If in a moving vehicle: *Handles traffic violations and more
  • Stop quickly and stay in the vehicle.
  • Move to a clear area away from buildings, trees, overpasses, or utility wires.
  • Once the shaking has stopped, proceed with caution. Avoid bridges or ramps that might have been damaged by the quake.
After an Earthquake
Pet Care *Handles traffic violations and more

The behavior of pets may change dramatically after an earthquake. Normally quiet and friendly cats and dogs may become aggressive or defensive. Watch animals closely. Leash dogs and place them in a fenced yard.

Pets may not be allowed into shelters for health and space reasons. Prepare an emergency pen for pets in the home that includes a 3-day supply of dry food and a large container of water.

Be prepared for aftershocks

Although smaller than the main shock, aftershocks cause additional damage and may bring weakened structures down. Aftershocks can occur in the first hours, days, weeks, or even months after the quake.

Help injured or trapped persons *Handles traffic violations and more

Give first aid where appropriate. Do not move seriously injured persons unless they are in immediate danger of further injury. Call for help.

Listen to a battery-operated radio or television for the latest emergency information.

Remember to help your neighbors who may require special assistance - infants, the elderly and people with disabilities.

Inspecting Utilities in a Damaged Home - Return home only when authorities say it is safe.
  • Check for gas leaks - If you smell gas or hear a blowing or hissing noise, open a window and quickly leave the building. Turn off the gas at the outside main valve if you can and call the gas company from a neighbor's home. If you turn off the gas for any reason, it must be turned back on by a professional.
  • Look for electrical system damage - If you see sparks or broken or frayed wires, or if you smell hot insulation, turn off the electricity at the main fuse box or circuit breaker. If you have to step in water to get to the fuse box or circuit breaker, call an electrician first for advice.
  • Check for sewage and water lines damage - If you suspect sewage lines are damaged, avoid using the toilets and call a plumber. If water pipes are damaged, contact the water company and avoid using water from the tap. You can obtain safe water by melting ice cubes.
Stay out of damaged buildings - Return home only when authorities say it is safe.
  • Use the telephone only for emergency calls.
  • Clean up spilled medicines, bleaches or gasoline or other flammable liquids immediately. Leave the area if you smell gas or fumes from other chemicals.
  • Open closet and cupboard doors cautiously.
  • Inspect the entire length of chimneys carefully for damage. Unnoticed damage could lead to a fire.
How the Public Can Help After a Disaster

When disaster strikes, people everywhere want to help those in need. To ensure that this compassion and generosity are put to good use, the media can highlight these facts:

  • Financial aid is an immediate need of disaster victims. Financial contributions should be made through a recognized voluntary organization to help ensure that contributions are put to their intended use.
  • Before donating food or clothing, wait for instructions from local officials. Immediately after a disaster, relief workers usually don't have the time or facilities to setup distribution channels, and too often these items go to waste.
  • Volunteers should go through a recognized voluntary agency such as the American Red Cross or Salvation Army. They know what is needed and are prepared to deal with the need. Local emergency services officials also coordinate volunteer efforts for helping in disasters.
  • Organizations and community groups wishing to donate items should first contact local officials, the American Red Cross, or Salvation Army to find out what is needed and where to send it. Be prepared to deliver the items to one place, tell officials when you'll be there, and provide for transportation, driver, and unloading.
Earthquake Trivia

When disaster strikes, people everywhere want to help those in need. To ensure that this compassion and generosity are put to good use, the media can highlight these facts:

  • Many people think of California as "Earthquake Country," but the state with the most major earthquakes is Alaska. The grandaddy of earthquakes was along the New Madrid Fault in Missouri where a 3-month long series of quakes in 1811-1812 included three quakes larger than a magnitude of 8. These quakes were felt over 2 million square miles.
  • The Richter scale was developed by Charles F. Richter in 1935. It is a logarithmic measurement of the amount of energy released by an earthquake. Earthquakes with a magnitude of at least 4.5 are strong enough to be recorded by sensitive seismographs all over the world. In the United States, several thousand shocks of varying sizes occur annually.
  • The effects of earthquakes are also measured by the Modified Mercalli Intensity scale. The intensity of a quake is evaluated according to the observed severity of the quake at specific locations. The Mercalli scale rates the intensity on a Roman numeral scale that ranges from I to XII.
  • The Loma Prieta (northern California) earthquake in October 1989 registered 7.1 on the Richter scale and as high as XI on the Mercalli scale.

Avoiding Earthquake Damage

Once an earthquake hits, it's too late to protect your home and belongings. But there are ways to limit future earthquake damage. Sometimes only a little time and a few dollars are all you need.

This homeowners' checklist will help you learn how to protect your home and belongings from earthquakes. It does not cover every method. If you're building or remodeling a home, there are many other options to consider for protecting your property.

To learn more, call the Emergency Management Department and Building Services Department. Other sources of information include professional home builders, architects, structural engineers and building supply retailers. And, remember to ask about building permit requirements.

If an earthquake occurs, take cover under a sturdy table or desk, cover your head and hold on to the table. If outdoors, move into the open, away from buildings, street lights and utility wires. You should also teach family members how and when to turn off the gas, electricity and water after an earthquake.

Do you know your earthquake risk?

In 1886 an earthquake struck the downtown Charleston area. Although no measurement scales were available at that time to measure the size of the earthquake, it is believed that the earthquake was considerably strong. Current seismology reports indicate that the Charleston area experiences small earthquakes on a regular basis.

Are televisions, computers and stereo equipment properly secured?

There are a variety of products designed to protect home equipment in an earthquake. These include adhesive-backed latches; nylon and elastic cords; wire, plastic and elastic guardrails; and shelf edges to prevent equipment from falling on the floor.

Is the house securely anchored to the foundation?

If your home has a perimeter foundation, make sure the sill plate of the house is securely bolted to the foundation. Consult with the Building Inspection Services Department before deciding what to do.

If your house has wood studs that extend from the foundation to the underside of the first floor (known as cripple walls), make sure they have adequate bracing, such as plywood or structural grade particle-board. The bottom of the bracing should be nailed to the sill plate. A variety of products called "hold downs" are available for securing walls to the foundation.

Test the wood near the foundation by probing it with a pointed instrument. If you can penetrate the wood easily, it probably has wood decay and should be replaced with new pressure-treated wood. Have a contractor inspect any deep cracks in the foundation.

Is the chimney properly secured?

Masonry chimneys pose a real hazard in earthquakes, especially the free-standing section above the roof line. To prevent the chimney from breaking away from the house, you may need to have it secured to the framing of the roof with sheet metal straps and angle bracing. Have the chimney inspected by a professional to determine the best method.

Are pictures, mirrors, shelves and light fixtures properly secured?

Anchor eyebolts to wall studs for hanging heavy items such as pictures, mirrors and shelving. Make sure picture wires are securely attached to picture frames. Hang things away from beds and places where people sit. Make sure overhead light fixtures and hanging plants are anchored to the structural support above the ceiling.

Is the water heater securely strapped in place?

Strapping the water heater to wall studs and having flexible gas and water lines installed will greatly reduce the risk of fire and water damage in an earthquake.

Water heater in corner or closet *Handles traffic violations and more Materials
  • 3/4" x 24 gauge perforated steel plumber's tape
  • 1/4" diameter x 3" lag screws and flat washers or 1/4" expandable anchors with 2" embedment for concrete or masonry walls
Directions
  • The water heater should be 1" to 12" away from the corner walls.
  • Locate the wall studs on both sides of the water heater (not behind it).
  • Anchor plumber's tape (a flexible steel strap) to a wall stud with a 1/4" diameter x 3" lag screw and flat washer.
  • From about 9" from the top of the tank, wrap the plumber's tape all the way around the tank in a clockwise direction. Then anchor the tape to the stud on the other wall. Make sure the tape is tight.
  • Repeat the process, again about 9" from the top of the tank, but this time wrap the tape in a counter clockwise direction.
  • Repeat the process two more times about 4" from the bottom of the tank. Wrap one band of tape in a clockwise direction and the other band of tape in a counter clockwise direction.
Water heater on straight wall *Handles traffic violations and more Materials
  • 3/4" x 24 gauge perforated steel plumber's tape
  • 1/4" diameter x 3" lag screws and flat washers or 1/4" expandable anchors with 2" embedment for concrete or masonry walls
Directions
  • The water heater should be 1" to 12" away from the wall.
  • Locate the wall studs on both sides of the water heater (not behind it).
  • Wrap plumber's tape around the tank 9" from the top and 4" from the bottom. Secure tape with round head machine screw, flat washers and nut.
  • Cut four pieces of conduit to size. The conduit is used as angle bracing from the wall studs to the tank.
  • Flatten 1" at each end of the conduit and bend 45 degrees. Drill holes 1/2" from each end.
  • Anchor the conduit to the wall studs. Use 1/4" diameter x 3" lag screw and flat washer. Then anchor the conduit to the plumber's tape. Use 1/4" diameter x 1" round head machine screw, washer and nut.

If you're using gas, have your utility company or a licensed plumber install a flexible hose where the gas line connects to the water heater at its base.

Install flexible hoses for the water connections as well.

Is heavy, tall furniture away from high risk areas?

Consider each piece of heavy, tall furniture in the house, such as bookcases, china hutches and storage racks. Ask yourself whether the item could fall over, hurt someone or block an exit in an earthquake. You can reduce the risk by moving furniture away from doors and places where people spend the most time such as couches and beds. You should also secure tall furniture to wall studs, as described in the next answer.

Are kitchen and laundry equipment securely anchored?

All large kitchen and laundry equipment should be securely anchored to the floor, wall or countertop, depending on the item. Such equipment includes stoves and ovens, built-in and countertop microwave ovens, garbage compactors, dishwashers, refrigerators and freezers, clothes washers and dryers, and ironing equipment.

Is heavy, tall furniture securely fastened to wall studs?

Anchor heavy, tall furniture to vertical wall studs, concrete or masonry with steel angle brackets. Even large, heavy objects that appear stable should be secured to the wall. The heavier the furniture, the stronger the restraints need to be. A heavily loaded file cabinet requires much stronger restraints to keep it from overturning than a light file cabinet with the same dimensions.

Make sure the screws penetrate the studs behind the wall. Gypsum board, drywall, plaster and other wall coverings are not strong enough to hold heavy furniture during an earthquake.

For wood studs (typically located 16 or 24 inches on centers), use a minimum 1/4" diameter by 3" lag screws. For metal studs, use #12 sheet-metal screws long enough to penetrate the flange material. For concrete or masonry walls, use concrete anchor bolts.

If wall studs do not line up with the furniture, consider installing a wood 2"x4" or steel horizontal mounting strip to the studs near the top of the items to be anchored. Furniture can then be anchored to the mounting strip without regard to the stud locations.

When possible, bolt file cabinets together (and to the wall studs) to form a more stable shape.

Are fuel tanks and wood-burning stoves securely anchored?

Fuel oil and propane tanks can slide or overturn in an earthquake, rupturing the tank or breaking the supply line and causing a fire. They should be securely anchored to the floor. Propane tanks are the property of the propane company, so you'll need written permission to anchor them. Ask whether the company can do it first.

Move tall, heavy objects that could fall and rupture the fuel tank in an earthquake. Have a contractor install a flexible hose connection between the tank and supply line, and where the supply line enters the house.

Wood-burning and other free-standing stoves also pose a fire hazard in an earthquake and should be anchored to the floor. Fasten stovepipe sections together to prevent separation.

You will most likely need a contractor for this work. Make sure all work conforms with local building codes.

Are heavy and breakable items properly secured?

Store breakable items such as bottled foods, glass and china in low, closed cabinets with latches. Keep breakable items in original packing boxes, when possible.

Keep heavy objects on lower shelves. Protect fragile items that could tip over or fall off shelves.

Install edge restraints (such as wood molding) on bookshelves and storage shelves, or use elastic cords or wire guardrails to keep items from falling off open shelves.

Install latches on kitchen drawers and cabinets to prevent them from flying open in an earthquake.

Are hazardous materials stored in secure places?

Store weed killers, pesticides and flammable products in closed cabinets with latches and on bottom shelves. Move incompatible chemicals to prevent mixing if the containers break.