Prepare your home

What happens during an Earthquake?


What really happens to your home during an earthquake?  The following videos demonstrate the impact that a significant earthquake can have on a home not properly prepared for a disaster situation.  The shake-table simulates shaking similar to that created by the 1994 Northridge 6.7M earthquake.

As you can see from the videos the chance of getting hurt by the way we decorate our homes is much more likely than by the home falling down around us.  

Video clips and photo courtesy of:
Richard Allen, University of California, Berkeley, Seismological Laboratory
http://seismo.berkeley.edu/~rallen/index.php

Consortium of Universities for Research in Earthquake Engineering (CUREE)
http://www.curee.org
More information at:
http://seismo.berkeley.edu/~rallen/seishaz/buildings/CUREEtest

Controlling Utilities

Following a disaster if utilities (gas, water, electricity) are damaged it may be necessary to turn them off. Emergency service providers and utility employees will be overwhelmed following the disaster, so it is important to know when and how to shut off your water, electricity and gas if you need to.

Emergency Gas Shut Off

Everyone in your family should know where the gas meter is located and how to turn it off. Most meters are at the front or side of the house. Some are put inside the building. In apartments or commercial buildings, they might be in the back. Don't turn off your gas if there is no leak. If you don't smell or hear gas escaping, you shouldn't turn off the gas. In the past we've taught people to turn off their gas no matter what. Unfortunately, the only safe way to turn the gas back on (after there has been damage to the line) is to have a certified technician come out. On a regular day this would not be a problem, but following a big disaster, individual homes will be the lowest priority. That means that you could be without gas service for several days or possibly months. But, If you do smell gas or hear a leak it's vital that you turn off the gas!

Here's how to do it: Locate the meter shut-off valve. It's usually the first fitting on the gas supply pipe coming out of the ground near your meter. Use a long-handled wrench to give the valve one-quater turn in either direction so that the lever is croswise to the pipe. Once the gas is off, leave it off.  Contact your gas company to inspect the system, check and relight appliances.

  

Water Shut Off

Water becomes a precious resource following a big disaster. Teaching everyone in the household how to turn off the water is important. Unlike gas, the water can be turned on and off with no safety concerns.  Your house has a number of sources for water, but if cracked lines pollute the water supply coming into your house or the effects of gravity drain the water in your hot water and toilet tanks, those sources won't be available. Following a major disaster it's wise to turn off the water until you hear from authorities that the water supply is safe.

Preparing to shut off water: Locate the shut-off valve for the water line that enters your house. Don't try to turn off the street valve at the cement box at the curb, this valve is extremely difficult to turn and requires a special tool. Your water valve may look like the picture to the left. Make sure that the valve can be completely shut off. Your valve may be rusted open, or it may only partially close. Make repairs before the day of the disaster. Label the valve with a tag for easy identification, and make sure all household members know where it's located.

    

Electrical Shut Off

Electrical sparks have the potential of igniting natural gas if it's leaking. It's wise to teach all responsible household members where and how to shut off the electricity. Just as with your water, turning your electricity back on doesn't pose a significant safety risk, although we recommend that you follow the steps below. 

Turning your electicity off and on: The first step is to locate your electrical panel or fuse box. A circuit box or panel will have a master switch that controls the entire panel. "Ramp down" to reduce the electricity gradually. If you have a circuit panel turn smaller breakers off first, then the main breaker.If you have a fuse box unscrew individual fuses first, then pull out the main fuse. FOR YOUR SAFETY: Always shut off all the individual circuits before shutting off the main circuit breaker. When turning the electricity back on, "ramp up" by starting with the master switch first, then turn on the individual breakers.

 Download PDF version of this information

If you're using a generator during a disaster make sure you use it safely by:

  • Not overloading it by powering too much
  • Not using it indoors even if it's portable
  • Following the safety recommendations for storing the generator and fuel
  • Connecting and running your generator correctly

To learn more about generator use click here

Earthquake proofing your home

Securing your home does not have to cost a lot of money or take a lot of time. Strapping down large pieces of furniture, making sure that wall hangings are secured into studs and hung in locations that don't create risk (like at the head of your bed) are just two steps you can take to reduce your risk of injury. Check out the links below for more detailed instruction on how to make your home safer.

Home Hazard Hunt

Take 30 minutes to go on a "Hazard Hunt". Imagine that the ground is shaking and you are in your "Quake Safe" location. Look around and think about the items in your house and if they are likely to cause injury or damage. The following checklist (Hyperlink) the will give you some questions to answer and focus your efforts to ensure your home is as safe as it can be. 

Retrofitting your home

Was your home built before 1980?

Prior to 1980, building codes did not require builders to secure houses to their foundations. This does not mean that every house built before 1980 is "unsecured", only that it was not a requirement. If your home is not properly secured, it may be at increased risk of "slipping" off the foundation during a major earthquake. Retrofitting involves bolting your home to its foundation and providing sheer/pony wall strength. The goal is to increase the structural integrity, but does not mean that your home is "earthquake proof" (there is no such thing). Retrofitting does increase the chance that your home will withstand the shaking and be intact following an earthquake. The good news is that wood framed construction, which is the primary building material in our area, performs well during earthquakes.  If you are considering retrofitting your home, you may want to check out a class offered by the Seattle Office of Emergency Management and the Department of Planning and Development. The class is offered for free and teaches homeowners :

  • How to evaluate your home to determine if it qualifies for the standard earthquake retrofitting plan
  • How to retrofit your home using Project Impact's Regional Home Retrofit guidelines
  • Tool usage and proper installation of parts
  • How to brace pony walls
  • How to secure the first floor framing
  • Which engineering solution can be applied to your home and when
  • The expedited permit process regionally and building code requirements (and why they are important)
  • Safety issues

The class provides demonstrations and each participant will receive a packet of literature and detailed drawings. The class is designed for all homeowners, whether you are planning to do the work yourself or hire a qualified contractor to do it for you. The cost of retrofitting depends on what needs to be done and if you can do some of it yourself. Materials can cost as little as a few hundred dollars. If you are not the do-it-yourself type the class will give you information on what to look for when hiring a professional contractor. Click here to get a list of contractors who have completed a six hour contractor training for home retrofit.

To learn more about the home retrofit process, get home retrofit plans, or apply for a permit visit the Department of Planning and Development website, the link is at the bottom of the page under "Earthquakes".  For additional information on dates and times go to Upcoming Trainings or call 206-233-5076.

Remember: If you are going to hire a trained contractor to retrofit your home, we still recommend that you attend a class to understand the process so you can be a better informed consumer.