Disaster Preparedness: 8. Earthquake

Before the Earthquake: Understand the Risk; Get Prepared |
During an Earthquake |
After the Earthquake: Turning Off Your Utilities? |
References: General | Tsunamis

hazard mapBefore the Earthquake

Understand the Risk

  • Cascadia Subduction Zone (CSZ): megathrust fault
  • 70-100 mi. offshore between Cape Mendocino (CA) & Vancouver Island (BC)
  • expect 8-9+M* event, lasting 3-5 minutes
  • involving a section or entire 1130 km (700 mi) fault length
  • occuring every 250-350 years, on average
  • causing: tsunamis; landslides; damage to homes, infrastructure,...
  • For some perspective, CSZ estimates compared to the Loma Prieta quake (10/17/1989, near Santa Cruz CA):
    Cascadia Subduction Zone (CSZ) magnitude: M8-M9 -- 10x - 100x stronger than Loma Prieta (M6.9)
    CSZ duration: 3-5 minutes -- 12x - 20x longer than Loma Prieta (15 seconds)
  • *M = Magnitude (Richter, etc.); MMI = Modified Mercalli Intensity;
    both are logarithmic; comparison: M vs. MMI
  • map 461Scientists began piecing together evidence for CSZ in the mid-1980s
  • Last occurrence: Jan. 26, 1700, ~9pm; ~M9; entire length
  • Japan: 'orphan' tsunami recorded -- precise date
  • Cowichan (BC): shaking so violent that they could not stand,
    so prolonged that it made them sick; collapsed houses;
    landslides; tsunami survivors lived 75+ feet above waterline
  • Hoh (WA): Thunderbird & Whale fight uprooted trees, shook mountains
  • Tillamook (OR): changed what they hunted, what they ate,
    how their houses were built, where they lived
  • Yurok (CA): jumping dance did not prevent tsunami -- ritual implies previous events
  • Geological record: 'ghost' forests, tree rings; sea slides / salt marshes
    -- past quake frequency, intensity
  • In 2010, OSU geologists predicted:
  • a 37% chance of a CSZ M8.2+ event within 50 years, and
  • a 10-15% chance that the entire Cascadia Subduction Zone
    will rupture with an M9+ event within the same time frame.
  • damageshakingA Cascadia event occurs every 250-350 years on average.
  • It's now been 320+ years since 1700,
    with many more people and structures.
  • We're "due" -- with greater likelihood than 2010
    estimates, and much more devastation than 1700.
    [on right: shaking intensity; damage potential]
  • Besides CSZ, other regional earthquake faults:
    e.g., 1993 Klamath Falls earthquakes M6
  • The Really Big One New Yorker; 7/13/2015;
    "'The Really Big One' is a story about [an earthquake and] a tsunami, that is destined
    to hit the Pacific Northwest, and we don’t know when. The tools of journalism employed
    there are just absolutely, absolutely incredible.... It is one of the greatest pieces of writing
    I’ve ever read." ~Ta-Nehisi Coates (in Ezra Klein interview; NYT)
  • video: Toast, tsunamis and the really big one; 14:13
    Chris Goldfinger, OSU; history of Cascadia; infrastructure damage; TEDx; 7/5/2016
  • video: iris.edu: Pacific Northwest Earthquakes: 3 Types;
    8:05 Incorporated Research Institutions for Seismology (IRIS); 7/19/2015
  • video: Cascadia 21:09;
    James Roddy, DOGAMI: Oregon Dept. of Geology and Mineral Industries; 12/1/2011

Get Prepared

  • video: Disaster Preparedness Training -- Earthquakes 1:40; CERT
  • Be sure your phone can receive Wireless Emergency Alerts;
    optional: install a ShakeAlert app for additional info, e.g., MyShake
  • Building survival depends on various factors: type & length of quake;
    construction type (wood vs. masonry); anchored to foundation?
    density of soil (rock vs. fill); construction / retrofitting publications,
    e.g., FEMA: Earthquake Building Science
  • video: Earthquakes and Unreinforced Masonry (URM) Buildings
    Portland Bureau of Emer. Mgmt.; 2016
  • picturebookcaseCheck with insurance agent about earthquake coverage.
  • Securely anchor gas appliances, water heaters, heavy furniture and
    light fixtures, wall décor, and fragile shelving contents (breakables);
    install cabinet latches?
  • valuablesfastenLocate utility shut-off valves and know how to turn them off.
  • Know where your fire extinguishers are, and check their status.
  • If living at or visiting the OR coast, know about evacuation
    routes: OR Tsunami Evacuation Maps
  • Bigger quakes may affect larger area, cause landslides, damage bridges -- especially at coast;
    we may be isolated in our neighborhoods for 2 weeks, probably longer, until outside help can arrive.
  • Store a #5. 2 Weeks Ready: Disaster Supply Kit (in a secure location)
    and have a #3. Family Communication Plan.
  • kitOrganize or attend a Map Your Neighborhood (MYN) meeting;
    neighbors can learn how to support each other more effectively.
  • Prepare an Under-the-Bed Kit [example on right]
    to safeguard against the most common injuries to head, hands, and feet --
    there will be broken glass; power may be out; it may be dark.
  • Include a hard hat, leather gloves, and socks & close-toed shoes,
    eyewear (reading and/or safety), flashlight w/ batteries, whistle,
    non-ferrous wrench (pictured: 4-in-1 tool for gas, water, dig, pry),
    MYN booklet, NOAA radio, tote bag, pet leash, ...;
    for additional people, add items or separate kits.

During an Earthquake

  • Pay attention to any early warnings: did you feel initial P-wave?
  • Receive notification? shakealert.org; video: 4:38;
    iris.edu: ShakeAlert; Be Informed: ShakeAlert
  • Put on your hard hat if under-the-bed kit is handy.
  • DROP! COVER! & HOLD ON!
  • tabledropIt may be difficult/unsafe to stand or run.
  • If you are inside, do not go outside.
    Interior door frames may collapse.
    Shelter under a sturdy table or desk, or near a wall
    away from glass and objects that can fall on you.
  • If you're in an unreinforced masonry building,
    e.g., Ashland City Hall, old school, etc., and you have enough warning time
    to exit safely, an open area (field, park) may be preferable.
  • If on unstable bridge, e.g., Medford viaduct, get off quickly or ...
  • If you are outside, check your surroundings
    -- stay away from obvious hazards such as older buildings, bridges and electrical wires, trees, etc.
  • If in a car, pull over to an area away from buildings, bridges, trees and powerlines.

oxygen fuel heatAfter the Earthquake: Proceed with Caution

  • Protect your head, hands, feet from broken glass, falling objects, etc.
    (under-the-bed kit).
  • Be aware of aftershocks. Assess your situation.
  • After shaking stops, if in a tsunami zone, e.g., on OR coast, go to higher ground:
    evacuate (probably on foot) within 15+ minutes to 100'+ above sea level.
  • Determine if your environment is safe to stay in.
    Turn off utilities if necessary.
  • typesUse your fire extinguisher on any small fires, e.g., typical household size for wastebasket-scale fires.
  • Types of fires & extinguishers: "ABC" for typical household use
  • Some fire extinguishers are rechargeable
    -- check label for recommended maintenance / replacement
  • video: 2:01; PASS: Pull pin, Aim nozzle, Squeeze handle, Sweep nozzle at base of fire
  • How to Know When It's Time to Buy a New Fire Extinguisher
    5-15 years? check pressure gauge; LH; 2/21/2021
  • Locate your MYN booklet (from your under-the-bed kit),
    along with updated neighborhood contact & resource summaries.
  • mynCalmly start to follow the 9 MYN Steps to coordinate with your neighbors.
  • Gather Critical Information. Tune to 1700 AM or NOAA stations
    -- see section 1. Alerts & Communication
  • Listen to directions from officials including emergency responders.
  • Be grateful that you had prepared to shelter-in-place
    -- section 4. Family Disaster Planning
    and have adequate supplies for several weeks -- section: 5. 2 Weeks Ready

elecgasTurning Off Your Utilities?

  • Only do so if leak or breakage is suspected
    as it may take weeks to months
    for utility providers to restore services.
  • Gas: Do you smell, hear or see a leak?
    Using a non-sparking, non-ferrous wrench
    (not iron or steel), turn the valve perpendicular to pipe flow.
  • Install a "California Valve" -- an earthquake-sensitive gas automatic shut-off valve?
  • Water: Turn valve to closed position on the home side. Valve is similar to gas valve.
    Besides controlling leaks, it could preserve clean water for later use.
  • power offCircuit Breakers: Turn off each individually before
    turning the main off, to minimize risk of electric shock;
    reverse process for turning back on.
  • videos: Turn Off Electricity; Shut off Gas
  • How to Stay Warm When the Power Is Out LH; 2/16/2021

References

Tsunamis