Earthquake

Photo: Damaged Bridge Earthquakes are described as the sudden release of energy occurring from the collision of crustal plates on the earth's surface or from the fracture of stressed rock formations in that crust. Though it can be said that there are many technical differences in the rocking, rolling, jarring and jolting felt during an earthquake, they can be devastatingly damaging and seriously unnerving.

King County is geographically located in an area known as the Pacific Ring of Fire, a distinctive zone marked by the prevalence of earthquake and volcanic activity. Washington State is framed by the Pacific, North American, and Juan de Fuca plates, which are segments of the earth's crust. A significant number of active fault lines or cracks in the crust have been identified in the central Puget Sound area including Seattle and King County. On an annual basis, thousands of minor earthquake events occur in the greater Puget Sound region. Most of these earthquakes go unnoticed by local residents since it usually requires a magnitude of 2.5 to 3.0 for a local trembler to be noticed.

King County has a long history of documented earthquake activity. The most recent significant activity was the Nisqually Earthquake of February 28, 2001. This earthquake, 10 miles northeast of Olympia in Thurston County (over 40 miles from Seattle), resulted in statewide losses exceeding $1 billion and injured 700 people, many in King County. Events like the Nisqually seem to reoccur about every 30 to 35 years, while events like the 1949 7.1 magnitude Olympia earthquake occur about once every 100 years. However, subduction earthquakes, events that occur along the interface between tectonic plates, can be spaced anywhere from 100 to 1,100 years apart, although the last recorded subduction event in Washington State occurred in1700. These great magnitude events can reach 8.0 to 9.0 on the Richter scale.

Earthquake Events Felt or Impacting King County:

Date	Magnitude	Location
April 1945	5.7	SSE of North Bend
February 1949	7.1	ENE of Olympia
April 1965	6.5	N of Tacoma
January 1995	5.0	NNE Tacoma
July 1996	5.4	ENE of Duvall
November 1996	2.9	Puget Sound
February 1997	3.0	SE of Seattle
April 1997	4.9	Puget Sound off Vashon Island
June 1997	2.7	Puget Sound
July 1997	3.1	Duvall
February 1998	2.9	NE of Seattle
March 1998	3.1	Pierce County
March 1998	2.9	Skykomish
July 1999	3.9	Tacoma
February 2001	7.2	Nisqually - Olympia
May 2002	4.2	Friday Harbor, San Juan Islands
May 2003	3.7	Bremerton, Kitsap County

Direct impacts from earthquakes may include damages to structures like buildings, pipelines, roadways and bridges. Secondary impacts from earthquakes are common and can include tsunamis/seiches and landslides.

Impacts to a community from earthquake events include injuries to citizens and public safety officials, damage to property and critical infrastructures, loss of vital services including electricity, gas, and communication systems, lost revenue and economic damages, and increased demand on public safety and infrastructure-related services. Washington State ranks second only to California among states susceptible to earthquake damages. Nationally, Seattle might incur the seventh largest potential dollar damages/losses.

Since King County is part of "Earthquake Country," being prepared for the next trembler is a key goal for your individual and family preparedness planning!

Hazard-specific Preparedness Steps

Find out if you live or work in a liquefaction area that may be impacted during an earthquake. While all areas within our region are susceptible to earthquake damage, liquefaction areas may be more vulnerable.
Pick safe places in your home where you could drop, cover and hold during an earthquake. Safe places could be under a sturdy table or desk or against an interior wall away from windows, bookcases, or tall furniture that could fall on you. Remember to do the same at work!
Practice drop, cover and hold. If you physically practice you'll have a better chance of remembering what to do during a real earthquake.
Have a fire extinguisher available and know when and how to use it. Minimum recommended size: 2A:10BC.
Seismically safeguard your home. This could include securing items such as appliances, water heater, book cases, framed pictures, televisions and computers; installing cabinet latches, and securing valuable/sentimental breakable items to shelves with putty.
If your home was built before 1977, check to see if the foundation is bolted to the frame.
Prepare for the possibility of a tsunamis/seiches, power outages and landslides.
See General Preparedness Steps below for more disaster planning basics.

Response Steps

During an earthquake, drop, cover and hold where you are until the shaking stops. If you are inside, stay inside - wait until the shaking stops and you are sure it's safe to exit. If you're in a multiple-story building and you must leave, wait until the shaking stops and use the stairs - do not use the elevator, which can be damaged during an earthquake.

If in bed - stay in bed and hold on, protecting your head with a pillow.

When outdoors - find a clear spot away from buildings, trees, and power lines. Crouch down low and cover your head.

In a vehicle - slow down and drive to a clear space away from overpasses, power lines, buildings, and trees. Stay in your vehicle, with the seatbelt fastened, until the shaking stops. Once the shaking stops, proceed with caution. Avoid bridges or ramps that may have been damaged.

After the shaking stops, check yourself and then others for injuries. Give first aid for serious injuries.
Check for and extinguish small fires and eliminate any fire hazards.
Check for gas leaks. Leave the gas on at the main valve unless you smell gas or suspect a leak; it may be weeks or months before professionals can turn the gas back on. If you smell gas or hear a blowing or hissing noise, open a window and quickly leave the building and turn off the gas at the outside main valve if you can.
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.
Check for damage to sewer and water lines. If you suspect damage to sewer lines, do not use toilets. If water pipes are damaged do not use water from the tap. Contact your local utility agency to report damage.
Inspect your home for damage. Get everyone out if your home is unsafe.
Monitor your NOAA weather radio and keep a local radio and/or television on for information and emergency instructions.
Use the telephone only to report life-threatening emergencies.
Expect aftershocks.

General Preparedness Steps

Have and practice a family disaster plan.
Establish meeting places and phone numbers in case family members are separated.
Identify an out-of-state contact to call during a major disaster or emergency; it will be easier to call out of the area if local lines are tied up.
Make sure everyone knows when and how to call 9-1-1.
Keep your disaster supply kits up to date. Make sure you have kits for your home, vehicle, work and school.
Get a tone-alert NOAA Weather Radio to receive emergency notifications and up-to-date information and instructions.
Teach all family members when, where and how to turn off utilities. Make sure you have the appropriate equipment, such as a wrench, handy.
Make sure you understand the emergency plans and expectations at your child's school and your work.
Preplan alternate transportation routes to and from work and other important destinations.
Be sure to keep at least a half-tank of gas in your vehicle at all times; power outages often accompany disasters and gas stations rely on electricity to power their pumps.
Know ahead of time what you should do to help family, friends or neighbors who are elderly or have special needs.

See "related links" for more details on how to prepare for, respond to, and recover from this type of a disaster or emergency.

Earthquake

Hazard-specific Preparedness Steps

Response Steps

General Preparedness Steps

Related Internal Links

Related External Links