The Big What?

by Celeste Barnes-Crouse

Someone recently asked me: “If an earthquake were to happen, would you rather be on a lower floor in a building where stuff could fall on you, or at the top of a building where you could be the thing that’s falling?” It made me question if Seattle is prepared for a major earthquake event. Many Washington State residents have heard the phrase “The Big One” tossed around lately, but what does it mean? Well, here’s the quick and dirty of it, along with some recommendations for what we can do to prepare ourselves.

Figure 1: Damage along a sidewalk from an earthquake in Chuetsu, Japan, Wikimedia Commons

“The Big One” refers to a major earthquake (magnitude >7.0 on the Richter Scale) possibly occurring in the Pacific Northwest region sometime over the next 50 years. We reside along the Cascadia subduction zone – the largest tectonic fault in the Pacific Northwest – where the Juan de Fuca tectonic plate is sliding beneath the North American plate. Subduction zones are characterized by large seismic events, like the 2011 Tohoku-Oki earthquake and the 2004 Sumatra-Adaman earthquake. An earthquake at the Cascadia subduction zone today could be as large as a 9.0 on the Richter Scale – 100 times bigger than a 7.0 earthquake. An event like this could cause a tsunami in coastal zones, more than $70 billion in damages, and upwards of 10,000 deaths. One study places the likelihood of a 7.0 event or greater in the next 50 years at ~1 in 3, and the United States Geological Survey (USGS) estimates the likelihood of a 9.0 at about 1 in 10.

Figure 2: The Cascadia subduction zone, Wikimedia commons

Geologic evidence suggests that “great earthquakes” (8.0 or greater) occur here approximately every 300-500 years, on average. Oral histories from local Native Americans, written records of an “orphan tsunami” (a tsunami event without a local earthquake) in Japan, and a variety of other scientific evidence helped scientists pinpoint the occurrence of Cascadia’s last great earthquake on January 26, 1700. Given that there have been relatively few significant earthquakes since then (six events larger than 5.0; notable events were the 1965 Puget Sound and 2001 Nisqually quakes), friction may be building up between the plates and could result in a major megathrust earthquake.

News reports say that Seattle may be in for a bumpy ride if a major earthquake were to happen soon. The Seattle Times called Washington State’s earthquake plan “inadequate” and our infrastructure “woefully unprepared.” However, we can look at this as an opportunity for us to prepare ourselves as best as we can to limit our risk of injury. Being informed and well-equipped are the most effective things we can do to prepare for an earthquake.

Here’s what you can do:

#1: Know what to do

Drop, Cover, & Hold On!

DROP to your hands and knees when you feel the shaking from an earthquake, so you can move to a safer spot.

COVER your head and neck with one arm and try to get underneath a desk or table – something to protect you from falling objects. If nothing is nearby, get away from glass windows and anything hanging above you. Curl up to protect your body and cover your head and neck with both hands.

HOLD ON to a leg of the desk or table so it will not shift away from you. Wait for the shaking to stop. Evacuate from the building if it’s safe to do so, and make your way to a safe place. Avoid hazardous debris and fallen power lines. If it is not safe for you to evacuate, stay where you are and call or signal for help.

 

#2: Get an earthquake kit

Have a kit to keep you going until emergency response can help. It’s best if you have one kit at home, one at your workplace, and one stored in your vehicle. You should prepare for a minimum of three days; however, Washington Emergency Management now recommends a kit to sustain you for two weeks.

BASICS TO INCLUDE:

  • Non-perishable food, water (or water sanitation solutions i.e. purification tablets or drops), and first aid supplies for each person in your household
  • Any prescription medications
  • Extra clothing & sturdy shoes
  • Flashlight
  • Radio
  • Personal identification documents

Check out the CDC website for an extended list of things to include.

Places like REI and Amazon sell convenient pre-packed kits as a great start if you don’t want to gather each piece separately on your own. Make sure to go through any kit you purchase so you know what’s included and what you may want to add.

#3: Make a plan

PLAN with friends or family so everyone knows how you will contact each other in an emergency. Make sure each person has important contact information available to them in case you’re separated.

CHOOSE a safe location where you will reunite following an earthquake. This could be a community center, workplace, or school where there will be supplies and other people to help. Plan to meet here; this way, even if communication lines are down, you will know where to find each other.

Earthquakes can seem scary because they occur suddenly and are difficult to predict. If we stay informed and prepared, we don’t have to feel scared! We can minimize the dangers to ourselves by knowing what to do before, during, and after a big event. So, let’s get ready to rumble.