Geologic Hazards in WA
Maximilian Dixon – Earthquake Program Manager July 28, 2018 Washington’s Earthquake Hazard
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According to the Federal Emergency Management Agency (FEMA), Washington State has 2nd highest earthquake risk in the United States.
More than 2,500 earthquakes occur in Washington each year. Estimated Probability of Approximate Earthquake Source and Example Events Occurrence in 50 Years Recurrence Interval Deep Earthquakes • 2001 Nisqually, M6.8 84 Percent 30 – 50 Years • 1965 Seattle-Tacoma, M6.5 • 1949 Olympia, M6.8 Cascadia Subduction Zone 10 – 20 Percent 200 – 600 Years • 1700 January 26 Event, M9.0 (est.) Shallow/Crustal Earthquakes 5 Percent 1,000 Years • Seattle Fault, M6.5 or greater • Random 6.5 or greater 15 Percent 333 Years Deep (Benioff Zone) Fault Earthquakes
• Nisqually Earthquake in 2001 • Magnitude 6.8 • 11 miles northeast of Olympia, Washington • 31.6 miles deep • Amazingly, there were no deaths, ~400 injuries • Estimated losses of $1 - $4 billion
Deep EQ: Less damage to Infrastructure and fewer aftershocks
Courtesy: USGS, Shallow / Crustal Fault Earthquakes
• Seattle Fault • Magnitude 7.2 • At least 4 earthquakes within the last 8,000 years. The most recent was 1,100 years ago.
Shallow EQ: More intense shaking, heavy infrastructure damage and more aftershocks Summary of significant losses in the M7.2 Seattle fault earthquake scenario. Among the counties most likely to be affected are King, Kitsap, Mason, Pierce, Snohomish, and Thurston. Shallow / Crustal Fault Earthquakes
South Whidbey Island Fault • Magnitude 7.4 • At least four earthquakes in the last 16,000 years. The most recent was less than 2,700 years ago.
Shallow EQ: More intense shaking, heavy infrastructure damage and more aftershocks Summary of significant losses in the magnitude 7.4 southern Whidbey Island earthquake scenario. The counties most likely to be affected are Island, King, Pierce, San Juan, Skagit, Snohomish, and Whatcom. Shallow / Crustal Fault Earthquakes
Devils Mountain Fault • Magnitude 7.1 • At least 2 earthquakes: 1,100 – 2,200 years ago; and 100-500 years ago.
Shallow EQ: More intense shaking, heavy infrastructure damage and more aftershocks Devils Mountain Fault Impacts
Summary of significant losses in the magnitude 7.1 Darrington - Devils Mountain Fault earthquake scenario. The counties most likely to be affected are Island, Jefferson, King, San Juan, Skagit, Snohomish, and Whatcom. A M9.0 Cascadia earthquake is estimated to cost $49 Billion
These large quakes recur every 200–600 years
The last one was AD 1700 (318 years ago) Landslide damage is usually not covered by insurance
Landslides are one of the most frequent natural hazards, but are difficult to predict or quantify 13 What is ShakeAlert?
• The ShakeAlert system detects an earthquake and rapidly disseminates warnings to end users in potentially affected areas. • The system currently operates as a production prototype in California, Oregon, and Washington. • ShakeAlert does not yet support public warnings. How ShakeAlert works:
P-waves
S-waves What is Earthquake Early Warning (EEW)?
In the U.S., EEW is the combination of: • ShakeAlert system technology • Recommended protective messages communicated to end users • The outreach, education, training, and other risk reduction activities required to fully implement EEW What could we do with EEW?
• Slow down trains so they don’t derail • Stop elevators at the nearest floor and open the doors so people can escape • Notify people so they can move away from hazards and protect themselves • Automatically divert inbound aircraft away from an airport that might be impacted • Shut down industrial processes to protect property • Suspend or initiate financial or critical data transfers and save vital data • Stop surgeries What is a Successful EEW System?
• The ShakeAlert system adequately detected an earthquake and rapidly disseminated warnings to end users in potentially affected areas • The end users received the warnings and took the recommended protective measures • The receipt of the warning and resulting protective actions (individual and automated responses) enhanced public safety
What is a Tsunami? Distant vs Local Tsunamis
Local Tsunamis: The first waves could reach the Washington coast within 15 to 20 minutes.
• Cascadia Subduction Zone Fault
• Seattle and Tacoma Faults Distant Tsunamis: Waves higher than 3 feet could reach the Washington coast within 3 hours or more.
• Alaska 1964
• Tohoku 2011
Waves only a couple feet high… Tsunamis can be generated across the Pacific or locally
A tsunami from a Cascadia earthquake will hit Seattle in <2.5 hours and be up to 6' tall
2011 Tohoku tsunami (Japan) ~$300B damage 15,894 fatalities Cascadia Subduction Zone – L1
2 Tsunami Warning Centers
Pacific National Tsunami Tsunami Warning Warning Center Center (Honolulu, HI) (Palmer, AK) Role of the National Tsunami Warning Center Process for Issuing a Tsunami Warning
Page 30 During a Disaster
First Local Disaster Response Local EOC Mutual Aid Occurs Arrives at Activated Requested Scene
State Proclamation County EOC Activated
President State EOC Declares Activated Disaster Preliminary Damage Assessment
Recommendation
FEMA FEMA Director Evaluates Presidential Disaster Reports To Reports To Reviews Damage & Declaration Requested Request Requirements
Tsunami Alerts NOAA Weather Radio
• 16 Stations in Washington • Warning Alarm Feature • NWS Portal into the Emergency Alert System (EAS) Wireless Emergency Alerts All Hazard Alert Broadcast Sirens
• OUTDOOR Tsunami Warning System
• Activated upon receipt of a Tsunami
WARNING from the NTWC
• Wailing Tone followed by verbal
warning in English and Spanish
• Coverage areas focus on major
population centers WA AHAB Sirens Regular Siren Tests Stay Informed
40404 “Follow NWS_NTWC”
https://www.facebook.com/NWSNTWC Tsunami.gov • Visually displays which coasts are impacted • List ALL tsunami alert messages (public bulletins) • In chronological order • Only look for messages titled AK/BC/US West Coast • As of result of Jan 23rd event, NOAA has dedicated more servers to support event spike traffic
7/30/2018
It could save your life!
Get Off and Stay Off the beach Guidance for Safe Minimum Offshore Depth for Vessel Movement
Distant Source Local Source (ships State/Territory Notes (ships in harbor)* at sea)*
Evaluated; may add potential safe areas within large bays 30 fathoms 100 fathoms California and ports
Evaluated, but is re-evaluating based on new data; also 30 fathoms 100 fathoms Oregon evaluating Columbia River
Evaluated; ships should be at least 1/2 mile from shore for 30 fathoms 100 fathoms Alaska all scenarios
Washington 30 fathoms 100 fathoms Evaluated; special conditions exist inside Puget Sound
Evaluated; implemented in Coast Guard plan in some 50 fathoms 50 fathoms Hawaii locations
* Ships also recommended to be a minimum of ½ mile from shore or fringing reef Plan to be on your own
Help will be slow in coming
Know the ‘natural warning signs’ FEEL, SEE, HEAR, RUN!! Know what areas are at risk Practice evacuations (Walking) Know your evacuation routes, Have multiple routes, Walk the routes Do not count on being able to drive Be prepared to be on your own for a while!
• mil.wa.gov/preparedness
• geologyportal.dnr.wa.gov
• www.tsunami.gov
• earthquake.usgs.gov/ens/register