Is your house, condo, or apartment strong enough to withstand an earthquake? Many people assume that since the U.S. has good building codes, they make us safe. While it is true that good building codes are safer, the best building codes in the world does nothing for buildings built before the code was enacted. Although building codes used in California have some of the strictest seismic provisions in the world, many older buildings have not been “retrofitted” to meet current standards. Retrofitting—fixing problems in older buildings—is the responsibility of a building’s owner.
Earthquake insurance is also an option, but can be prohibitively expensive and I therefore I don't recommend it. In many cases, 2-3 years of earthquake insurance would pay for a full seismic retrofit. If your dwelling gets damaged in an earthquake, it might also take years to get everything rebuilt or repaired - assuming the insurance company pays up. Personally, I would rather rely on engineering than insurance companies. [disclaimer: I am the son of an engineer]
Structural-Safety Quiz for Single-Family Home or Duplex
If you live in a single-family home or duplex, the strength of your home depends on when it was built, its style of construction, and its location. Use the quiz below to see if your home is likely to be so badly damaged in a future quake that people might be injured or that it would be unsafe to occupy.
1. When was your home built?
- Before 1960 = 5 points
- 1961-1978 = 3 points
- After 1978 = 1 point
- 2 or more stories with living area above a garage = 5 points Split level, on a hillside or gentle slope = 6 points
- 1 story, 3 or more steps up to the front door = 4 points
- 1 story, less than 3 steps up to the front door = 1 point
- Portions of the Bay Area shown as yellow or green in color on the shaking hazard map = 5 points
- Elsewhere in the Bay Area (shown as orange and red) = 7 points
TOTAL POINTS =_____
If your home scores 13 or more points on the quiz, you probably should have an engineer, architect, or contractor evaluate it unless it has been strengthened in the past few years.
They will check to see if it is strong enough to keep you and your family reasonably safe in a quake. The latest recommendations of structural engineers, contractors, and city building officials who are experts on retrofitting are available on the ABAG web site at: http://quake.abag.ca.gov/residents/steps/
The “soft” first story of this apartment building collapsed in the 1994 magnitude 6.7 Northridge earthquake, crushing cars below and severely damaging the floors above (FEMA photo).
If you live in a condominium or apartment...
Many condominiums and apartments have parking on the ground floor. These weak or “soft” first stories may lean or collapse in an earthquake.
Some multi-story buildings in the Bay Area can have problems because they were constructed before 1972 of concrete or brick that is inadequately reinforced. Many cities have requirements that these buildings be seismically retrofitted. You are less likely to be killed in a retrofitted building, but you may not be able to reoccupy it after a quake.
As a renter, ask your landlord these questions:
- What measures have been taken to ensure the seismic safety of this building?
- Have water heaters been strapped to the wall studs?
- Can I secure bookshelves and furniture to the walls?
Go to http://quake.abag.ca.gov/residents/homequiz/mf/ to take a quiz to see if your apartment building or condominium may need retrofitting. This Web site also has links to information that can help your landlord find appropriate ways to improve the strength of your building.
This chimney broke and nearly fell in the 1969 magnitude 5.6 Santa Rosa earthquake (photo courtesy NISEE).
Brick chimneys can collapse if shaken...
Stay away from chimneys and fireplaces during shaking! Collapsing chimneys cause many injuries in earthquakes—60,000 chimneys fell in the 1994 magnitude 6.7 Northridge earthquake.
You can reduce the chance of bricks falling through the ceiling in a quake by putting sheets of plywood above ceiling framing. However, “retrofitting” masonry chimneys with bracing or strapping is not an effective safety measure, because they may still fall as a unit when exposed to strong shaking. The best plan is to get rid of that dangerous old brick chimney and replace it with a modern metal flue. If you are concerned about how it looks from the street, you can put a wooden chase around the new metal flue to keep the architectural style the same.
-Paul
