Most of us in the Northwest know we live with the threat of earthquakes, but many of us limit our preparations for disaster by reminding ourselves to buy a case of water the next time we’re at Costco.
For those who happened upon a New Yorker article that went viral on Facebook last week, the magnitude of the threat was brought into much sharper focus. “The Really Big One,” by Kathyrn Schulz, features interviews with seismologists, archeologists and disaster management officials and maps out the science, the time frame and our vulnerability to disaster in the Pacific Northwest.
A quick look at the numbers from Schulz’s reporting makes it clear why we must pay attention. The Cascadian subduction zone is due for either a magnitude 8.0 to 8.6 quake, “the big one,” or a quake of magnitude 8.7 to 9.2. “the very big one,” in which the ground beneath our feet could drop six feet and shift west by 30 to 100 feet in a matter of minutes. With some of that land dropping and shifting on the sea floor off the Washington and Oregon coast and Washington’s Salish Sea and Puget Sound, that adds the destruction from tsunami. Those at higher ground face the threat of landslides.
It’s the job of the Federal Emergency Management Agency to prepare for the worst. This is what the worst looks like to a regional FEMA official: “Our operating assumption is that everything west of Interstate 5 will be toast.”
Of the 7 million people along Washington and Oregon’s I-5 corridor, FEMA’s projections following the “very big” quake and resulting tsunami would be about 13,000 dead, 27,000 injured, 1 million without shelter and 2.5 million without food and water. It could take one to three months to restore electricity; six months to restore water and sewer services and six months to rebuild roads and bridges.
What often gets in the way of taking such warnings seriously is the inability to know when such a quake will hit. It could happen later today or long after those now living are gone. But history and geology allow a rough estimate that should make us stop and think.
Scientists believe the Cascadia fault averages a significant quake about once every 243 years. With its last quake pinpointed to 1700, that means we’re about 72 years past the average. The seismologists in Schulz’s article estimate the chances for a quake up to a magnitude 8.6 in the next 50 years are 1 in 3; 1 in 10 for a quake up to 9.2.
Imagining the worst can lead us either to fatalism, a resignation that the “really big one” simply can’t be prepared for, or to action. There’s guidance in the response following the 2011 Tohuku, Japan, earthquake and tsunami that killed nearly 16,000, as there is in our own response to last year’s Oso landslide. We learn from each disaster and use those lessons to direct our preparation.
We can assemble food, water and other supplies and prepare our homes, but we also should think out how to react during an emergency, where and how we will contact and meet with family. Prepare for tsunamis by thinking about where you live, where you work and where your children learn and play. When in areas near the shoreline or at or near sea level, think about how you would get to higher ground. Depending on the quake’s epicenter, you may have only minutes to leave the area. The state Department of Natural Resources has maps and other information online at tinyurl.com/WaDNRHazardMaps to show where the risk of inundation from tsunamis is highest.
Much more information is available at FEMA’s www.ready.gov, the National Center for Disaster Preparedness at ncdp.columbia.edu and the American Red Cross at www.redcross.org/prepare.
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