Welcome to part 2 of Surviving Cascadia’s “During the Shaking” info. If you haven’t read part 1, Drop, Cover, Hold On (DCHO—the “Stay” page for this “Stay or Go” discussion) it covers some very important topics. Please start there.
While Drop, Cover, Hold On is the best protective action for most people in most situations, the devastating reality is that some Pacific Northwest buildings are at risk of experiencing partial or complete collapse in a major earthquake.
Oregon State University Professor Emeritus, Chris Goldfinger is one of the world’s leading experts on subduction zones. He is interviewed in the PBS video above and offers his opinion in this Temblor article, as well.
February 6th, 2023, brought gut-wrenching heartbreak to the world as three massive earthquakes and hundreds of aftershocks struck Türkiye and the Syrian Arab Republic.
The first—a massive M 7.8—struct the southern Turkish province of Kahramanmaras. Rupturing between the Anatolian and Arabian plates, the earthquake lasted 78 excruciating seconds. It was followed by a magnitude 7.5. A 3rd devastating earthquake measuring a 6.3 struck on February 20th.
“The earthquakes in Türkiye, impacting Türkiye, Syria, and other nations, have caused an unbearable loss of life and injuries across the region.”
—The United States Geological Survey (USGS)
After the devastating earthquakes, KGW conducted an interview comparing the earthquakes in Türkiye to a potential Cascadia event, bringing to light the roughly “1,600 older unreinforced masonry buildings in the region that wouldn’t be able to withstand a major earthquake”. Of course, Portland isn’t the only Pacific Northwest city with URMs. Here are some other related statistics.
| Oregon Resilience Plan: At the time of publication, roughly 1,000 public school buildings had a rating of high or very high risk of collapse. |
| University of Oregon’s All Things Cascadia: “In short, many Pacific Northwest public schools are at risk of falling down on their occupants during a Cascadia megathrust event.” |
| State of Oregon Cascadia subduction zone catastrophic earthquake and tsunami operations plan: 1) Estimated 25,000 injuries as a result of collapsed buildings, 2) “Every coastal hospital will either be completely or extensively damaged in this scenario.” 3) “Most facilities in the Willamette Valley and Southern Oregon will suffer complete to moderate damage” 4) One quarter of all examined public safety buildings carried the same risk |
| Washington Military Department, Washington State Department of Natural Resources, USGS & FEMA: “Structural collapse (complete damage) of thousands of buildings [in Washington] is also expected (more than 3,000 in Clallam County).” |
| Spokesman-Review: “Many of the older buildings in Seattle and elsewhere in Western Washington are not built to withstand the Big One. Buildings made of unreinforced masonry, like many of Spokane’s older brick buildings, or inflexible concrete are particularly susceptible to collapse.” |
More troublesome, even seismically retrofitted URM buildings may not withstand a Cascadia earthquake. In a 2023 Temblor article, a team of experts “worked with practicing structural engineers to design a test structure that would directly mirror today’s real-world retrofits.” They wanted to see how it would hold up during shaking… This 25-second video is eye-opening. *Keep in mind, a Cascadia megathrust earthquake is expected to shake anywhere between 3 and 7 minutes.
The building in that video was retrofitted to be code compliant for life safety. It’s worth noting that not all seismic retrofits are created equal. This image below, from the City of Portland, shows how some retrofitted buildings may not even meet that standard.
That is not to say that retrofits aren’t worth doing! Many types work quite well. This video from FEMA’s Residential Seismic Rehabilitation Course P-593 shows that some retrofits, done well, prevent collapse. In this video, the home in the foreground has not been retrofitted, while the home farther back has been. Watch what happens when they shake on the table.
This video is 22 seconds long. A reminder that the next Cascadia Subduction Zone earthquake is expected to shake for at least 3 minutes.
It is this added layer—the potential for building collapse—that is worth consideration. Oregon Law recognizes the need to practice protective actions other than DCHO (the “Go” option in “Stay or Go”) in certain buildings. The following Oregon Revised Statutes (ORS) state the following nearly verbatim verbiage.
| Schools | State and Local Agencies | Private Employers |
| 336.071 Emergency procedures; preparing for and recovering from emergency events. (2)(b) Drills and instruction on earthquake emergencies shall include the earthquake emergency response procedure known as “drop, cover and hold on.” A school may drill earthquake emergency response procedures in addition to “drop, cover and hold on” when the school determines, based on evaluation of specific engineering and structural issues related to a building, that “drop, cover and hold on” may not be the most effective earthquake emergency response procedure to prevent or limit injury or loss of life. | 401.900 State and local agency earthquake drills: (4) Consistent with rules of the department, the state or local agency may drill earthquake emergency response procedures in addition to “drop, cover and hold on” when the state or local agency determines, based on evaluation of specific engineering and structural issues related to an office building, that “drop, cover and hold on” may not be the most effective earthquake emergency response procedure to prevent or limit injury or loss of life. | 401.902 Private employer earthquake drills: (4) Consistent with rules of the department, the person may drill earthquake emergency response procedures in addition to “drop, cover and hold on” when the person determines, based on evaluation of specific engineering and structural issues related to an office building, that “drop, cover and hold on” may not be the most effective earthquake emergency response procedure to prevent or limit injury or loss of life. |
If we have laws allowing for the practice of essentially getting out of a building rather than practicing DCHO, shouldn’t we be expanding the conversations and messaging to reflect it? FEMA has begun doing just that, though it takes a little excavating to reach the information.
FEMA’s Protective Actions page for earthquakes mentions the need for other actions in certain circumstances. Scroll down until you get to the Research section. Click the “View Research Summary”.
After clicking “View Research Summary”, read the entire page!! Good foundational information will help you make decisions when the time comes. The Messaging Focus paragraph (copied here for easy viewing) contains information about the Stay or Go option.
Once more, not all buildings will fare the same when the shaking hits, as shown by this image below. That single fact should be taken into consideration; especially now that ShakeAlert may offer a few seconds (up to a minute) of time to get out before shaking starts. Here is the link provided on our During the Shaking: DCHO page that explains what ShakeAlert is and how it works.
Seattle Emergency Management also has a useful page with GIFs embedded, and they provide the following video in which Nancy Devine, P.E, S.E., Senior Structural Plans Engineer for the Seattle Department of Constructions and Inspections discusses Identifying Unreinforced Masonry URM Buildings.
It’s worth noting that there is inconsistent research on whether to “Stay or Go”. FEMA’s Earthquake | Evacuation: Exiting an Unreinforced Masonry Building page provides the following two examples. Note that neither event occurred in the US, meaning building materials and building codes may vary from those in the Pacific Northwest.
| Example where it was more dangerous to exit URM buildings during an earthquake due to masonry falling into the streets and sidewalks below: | “Evacuating un-reinforced masonry buildings during the shaking appears to increase the risk of injury by a factor of three.” – Evidence-based Public Education for Disaster Prevention: Causes of Deaths and Injuries in the 1999 Kocaeli Earthquake. |
| Example where it was safer to exit URM buildings during an earthquake: | “The possibility for escape was crucial for survival and depended on the type of building… In the seven villages studied, all the deaths and injuries which occurred within 48 hours of the impact were associated with the collapse of houses.” – World Health Organization, A case-control study of injuries arising from the earthquake in Armenia, 1988. |
This page is not—I repeat— is NOT me telling you which choice is right for you. I’m not making any recommendations. I’m not qualified to do so. Instead, this page is intended to introduce you to the broader conversation so you can soak in both sides, talk with the experts about your particular situation, and make the choice that you think is right for you.
Surviving Cascadia 