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 felt.
Washington State ranks second only to California among states susceptible to earthquake damages. Nationally, Seattle could incur the seventh largest potential dollar damages/losses. Direct impacts from earthquakes may include damage to structures such as buildings, pipelines, roadways and bridges. Secondary impacts are common and can include tsunamis/seiches and landslides. Communities can also be significantly impacted in the following ways:
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
increased demand on public safety and infrastructure-related services
Since King County is part of "Earthquake Country," being prepared for the next trembler should be a priority for your business, individual, and family preparedness planning!
When the earth shakes... know what to do. (Video from Federal Emergency Management Agency)
A March 2011 KCTS 9 video, which provides helpful earthquake information and preparedness tips, features local earthquake expert Bill Steele and public educators from King County Office of Emergency Management and Seattle Emergency Management.
Earthquakes and the rumored "Triangle of Life":
Protect yourself during an earthquake - Drop, cover and hold on!
A popular, yet misleading, message is circulating on the Internet again for how to survive an earthquake by using the "triangle of life" technique. With images from Nepal's devastating earthquake still fresh on our minds, King County residents need to know "Drop, Cover and Hold On" is still the best method for earthquake safety in the United States and especially in our own quake-prone region. For more information, read our news article that was posted March 2011, shortly after Japan's large earthquake.
Earthquake exercises and scenarios
King County departments and partner agencies participated in an earthquake exercise Oct. 2010. Learn more. One of the products produced as a result of the exercise is an Earthquake Guide for Businesses (610 KB; PDF; 12 pages). It's a helpful tool for companies to facilitate earthquake preparedness in the workplace. Identify your organizational risks and hazards; then develop an emergency plan and train staff how to carry it out. In June 2016, we'll be participating in another, more robust drill - a four-day exercise to test existing plans and procedures for responding to and recovering from a 9.0 Cascadia Subduction Zone quake. Learn more.
Earthquake scenarios have been developed to identify possible areas of greatest vulnerability to earthquake damage. While they should not be viewed as absolute predictors, they can help emergency management professionals and residents think through "what if" challenges and develop contingency plans for disaster response and recovery. A great way to raise awareness of the importance of preparing for earthquakes, and how to react when the shaking begins, is participating in Washington State's annual "Great Shakeout". The video below details how you can get involved. Register today!
History of earthquakes in Washington State
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.
King County earthquake events with a 5.0 or greater magnitude:
SSE of North Bend
ENE of Olympia
N of Tacoma
Mount St. Helen
ENE of Duvall
Nisqually - Olympia
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 on. 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.
See the section General Preparedness Steps below for more disaster planning basics.
During an earthquake, drop, cover and hold on 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.