Sounder Bruce (Flickr)
Sounder Bruce (Flickr)

A month after the largest earthquake preparedness drills in Northwest history – “Cascade Rising” – I began wondering about the seismic preparedness of our transit systems, both current and proposed. I’ve written about transportation and natural disasters before, and though life-or-death situations rightfully make subway health the least of our worries, I do believe we have a moral duty not to assume that private vehicle access is a universal option in a crisis.

I asked Sound Transit’s Bruce Gray about their assets, mostly Link guideway (both elevated and tunneled). He responded in two parts, discussing the damage the system can take while still being operable, and the damage threshold that would cause the infrastructure to collapse or be fundamentally unsafe.

Gray said that the operational threshold is “a 150-year return period seismic event. If an earthquake like Nisqually happened again, Link could remain operational with minimal disruption as long as the tracks were clear and we were able to maintain power to the system.” In terms of structural safety, the design standard is a “2,500 year” standard, meaning that the systems are engineered to withstand the “Big One” that would destroy so much of our other infrastructure (including I-5)

It’s designed to avoid major failure and maintain life safety after the worst earthquake that experts can predict will happen every 2,500 years or so. Is this scenario Link would likely not be operational because of track blockages or power disruptions but the infrastructure would be standing. Backup systems would be able to power fire/life/safety systems in our underground stations but they would not be able to power the line.

In the news coverage of the drills, much focused on supply airlifts and strategies for rebuilding roads quickly to reopen access. Though these are critical of course, Link’s robustness should factor into disaster preparedness scenarios, too. If priority were given to restoring power to the line, freight and supplies could have a safe north-south artery on which to travel. Patients and officials unable to reach hospitals could reach temporary emergency facilities at UW. In any case, it’s good to know that what we’re building is resilient, even if we still have a long way to go as a broader community. Though feet and bicycles are the most resilient of all, we should think long and hard about the proper role for transit in natural disasters.

32 Replies to “Could Link Survive the Big One?”

  1. Even Tokyo’s lines were unoperable for a while after the 2011 quake and they have better earthquake preparedness than just about anywhere else on the planet.

    I don’t know how we can expect ours to do much better. The fact that the lines will survive is a pretty big deal.

    We’re going to have much more serious problems than a train line or two shut down when a major earthquake hits.

    1. Absolutely. A lot depends on how much damage is done to other infrastructure. BART played a significant role in moving people across the bay ( because the Bay Bridge was damaged and BART was still running. In our area it would mean several bridges damaged (I-5, Aurora, Fremont, Ballard, University). This could happen (the essential Link connection is all underground) but I doubt it. Meanwhile, BART is huge. They have 10 car sets capable of handling huge numbers of people. Link is not.

      In general, as long as the bridges are operable, fleets of trucks and buses are more likely to play a crucial role. They have higher capacity (for our region). They can go more places. But to do so they would probably need police or military escort. If you let things just happen, then you get gridlock (as that picture in the other page shows).

  2. I think Bruce said it best that Link’ will likely shut down but not because of a failed infrastructure, but from outside factors affecting the train. Power loss, blockages. . how many operators would choose work over their families after such a huge disaster?

    Nonetheless, it is interesting to know we would have little rebuilding after a quake. When things begin to return to normal, Link would probably have overwhelming ridership from people who can’t access roads being rebuilt.

  3. I’d like to have a geologist confirm, but have read that in some situations, the deeper the tunnel, the safer. Though, for instance, cut and cover, and stations, are different from tubes. Also, station entrances themselves could each have what’s left of a building covering the entrances.

    But Zach, let’s talk about freight and supplies. How exactly are we going to carry them? Let alone get them to the surface? Would standard freight cars fit? And how much freight, or rubble, can a LINK car couple up to and pull?

    Can elevators be converted? Has anybody talked to our own responders on this whole question? More than time.


    1. I’m a geologist but not a seismologist – can’t say too much. I can confirm that surface waves are typically the most destructive to the built environment, but a) I don’t know how deep the “surface” extends for surface waves, and b) part of why they are damaging is how they interact with structures built out of rigid rectangles – tunnels dont have many of those.

      If you want to know more, read up on the differences between P, S, and surface (Raleigh and Love) waves.

    2. Mark, yes, generally speaking, deeper tunnels are safer. It has to do with the type of material surrounding the tunnel. Bore a tunnel through bedrock and it will be likely to withstand shaking, as the surrounding material is structurally competent. Cut and cover a very shallow tunnel (yes, the DSTT), and it will be surrounded by, relatively speaking, much looser material, that is more prone to shaking. They do intensely compact this backfill material, but no mechanical compaction will ever compare to thousands or millions of years of settlement and consolidation.

      Here’s a link to a nice research paper, courtesy of Google, to help confirm:

      Keep in mind that literally every situation is different, no two soil types are the same, but in generalities, this is true.

  4. As an observer who spent the entirety of the Cascadia Rising event at the State’s Emergency Operations Center at Camp Murray, I can assure you that in the exercise’s scenario, LINK light rail was not considered. Under the scenario, the area’s airports and seaports were totally inoperable and power systems would be out for weeks, if not months. Some 50% of the region’s bridges were also unusable, and the mountain passes faced a 30+ day closure from landslides the size of Oso. Seattle’s Seaport is projected to be totally inoperable for at least 180 days and liquefaction will damage almost all of our region’s airport runways. The Army Corp of Engineers is predicting 1-million homeless and 2.5 million needing basic sanitation and water services in the Seattle area alone. With security and resupply routes being a problem for the planned points of distribution (PODS), for the first few weeks, people can expect the metro areas of Seattle and Bellevue to be completely ignored, as the nearest relief PODs will be set up in Everett and Renton.

    Also, even if LINK’s tunnels and elevated sections survived unscathed, in all likelihood, ground liquefaction in near the Stadium and SODO stations would severely damage the rail’s tracks and associated railbed. The lack of electrical services will also be troublesome for regional transit (remember, ferry dock hydraulic systems require electricity to operate). When viewed with the lens of the larger level of destruction and services outage, this system of transportation would not be a priority to repair, since the efforts will be largely focused on ways to get supplies into the region, vs. moving people around within the area.

    1. Agreed. The main transportation of goods will likely be national guard helicopters, the main mover of people will be feet.

      I’d also mention to everybody saying “since the tunnels will be fine…” – we really don’t know that. We expect that they won’t collapse and crush people underground, but there’s a lot of damage between how they are today and total collapse.

      1. An amazing resource to watch is the 2015 Oregon Public Broadcasting’s “Unprepared” series about a Cascadia Mega-quake striking the region. Although it deals mainly with Oregon’s issues, many of the lessons and infrastructure engineering issues they face are quite similar to Seattle’s. The documentary recently won an Emmy Award for public service.

    2. Thanks for the sobering perspective of life after a 9.0 EQ
      I also participated in the exercise and know limited resources will be directed towards keeping the injured alive, then sheltering the hundreds of thousands of victims from the elements, then providing drinking water and then food.
      Self preparation is the best plan from a personal perspective. We’re mostly on our own for the first couple of weeks.
      A recent FEMA class I took on Community Resilience concluded that communities that prepare generally bounce back. Those that don’t perish.

      1. Mic, pretty sure you and I think alike about this, but I want to clarify what “On our own” will mean in Seattle and this region. The “Our” part really says it.

        Anybody whose been in the service can testify that, especially in a mild climate with enough water to make it this green, people can live for years or more with mud and gravel for roads and tents for roofs.

        And trucks and tractors for LINK. And correctly- installed sharp-sided ditches for plumbing. Sustainable because they’re waterless, don’t you know. And no shortage of people to assemble, maintain, and dig these things.

        Probably less unemployment and homelessness than now. Not having to sacrifice family time to drive trains because their wives could be driving the truck, or or bus – wood works for fuel- and I think after WWII, there was a mechanism for burning wood directly into flammable gas.

        Most aggravating of all will be that little kids of prime train-loving years will be really bugging their folks about how GREAT! this all is, and how they never want to go back to Borrrrr-ing old (name the bus route.)

        Also, pretty sure that some deadly parts of Syria have cell-phones. And FaceBook and Twitter that somehow barrel bombs can’t touch. (War is Hell!)

        But also, we’ll still be in the United States of America. Which is big enough, and Seattle small enough, that unless the Yellowstone Caldera blows up and makes everything between California and Chicago uninhabitable (no they’re NOT right now!) we’ll still have millions of people in short-flight distance to load stuff on the helicopters.

        Meaning that on the scale of the whole rest of the world, we’re still part of a country 4000 miles North-South by 2500 miles East-West across by 300 million people who all think we belong to the same country. Out of range of our earthquakes.

        Most of whom will respond competently and automatically to an emergency without a single order. And governmentally probably the least corrupt part of it. Which, as opposed to some other places with recent disasters, should really cut the body count.

        New Orleans 2005. Hurricane Katrina Read it and puke.

        Mark Dublin

  5. There are different levels of earthquakes, where Link can play different roles. If Steve A is right that with the Big One there will be no supplies for three weeks and no electricity for weeks or months, then Seattle would be like a mideast civil war without even refugee camps, although hopefully without mass killing either. I’m concerned about people in apartments who don’t have room to stockpile food, and interior stairways that are pitch black (can you find the 5th floor door? or your door in the hallway?), and card-access doors that don’t work, which could make the apartment buildings uninhabitable. It’s hard to believe they could just ignore the largest concentrations of people for three weeks.

    But in an earthquake like Loma Prieta where only a few bridges fail, then Link could have more of a role, but not as big as BART. BART connects the two largest population centers in the central Bay, and it was also critical because firefighters and teachers couldn’t afford to live in San Francisco so they were all in the East Bay. The closest equivalent in population is Seattle and Bellevue, and that has the I-90 bridge in between. If the quake or extreme water level doesn’t destroy the bridge, it could slip it out of alignment at the connection joints enough to make the train tracks unusable. So that could hinder Seattle/Eastside connectivity, although of course people could drive around the lake, as long as not too many people try to do it simultaneously. But Link’s north-south axis could be in pretty good shape. That would give mobility in the areas it serves, which is not everywhere but at least it’s something.

    As for carrying freight on Link, that sounds dubious. You could hand-load supplies into a Link car but that wouldn’t be very much and it would be labor-intensive, plus displacing passengers. As for putting other trains on the Link tracks, they probably wouldn’t fit in the tunnels and they don’t have pantographs, and would we allow diesel vehicles in the tunnels? But we don’t have to use Link because there’s a BNSF track parallel to it. Even if the downtown tunnel is damaged, trains could still probably go from SODO on south. It’s an open right of way around them so the main question is whether the earthquake would damage the tracks (or overpasses fall on the tracks and block them). That I don’t know: are mainline railroad tracks resilient in earthquakes? Especially American ones that aren’t in the peak of maintenance.

  6. To clarify I wasn’t thinking about using Link trains for freight, but a fleet of hi-rail vehicles

    1. Suggest immediate click to Zach’s own 2011 posting, noted in this one. Thanks, Zach, and EHS, and Steve. I’d also like to see some more technical details for emergency preparedness, and transit engineering itself.

      But measures that could make us the safest the fastest, and also leave us feeling the least helpless, are skills, tools, training and habits that’ll both take advantage of whatever powered machinery is left to us, and how much we can get done without any.

      Shovels. Wheelbarrows. Perfect Seattle example: bicycles! And everything that can be bolted onto them and pulled by them. Which, if they’re the only wheeled thing we can get into a transit tunnel can still save lives and get things fixed.

      And plain ordinary first aid. Force 9, 500 pound bomb, pressure cooker, or broken window, ripped shirt can be bandage or tourniquet. Given somebody trained to use it, and simultaneously get other people to do the same.

      Communications? Talk about Designated Front Runner for worst future body-count! Tell us again how info handled a couple puffs of pepper spray last week. Can anybody else see a hundred dead people over something they got told wrong, or not at all? Including that there’s no threat whatever?

      Coordination, cooperation…Reason I won’t let up on DSTT operations is that the present attitude governing vehicle control there needs no help from an earthquake.

      Mark Dublin

  7. Forget Link, which of all our county transit lines are most in danger from “the big one?” How about a packed route 512 bus crossing the ship canal bridge just as a 9.0 hits? What about a 9.0 just as Link is approaching the Montlake cut?

    New post assignment. I want to see a top ten list of transit lines that would be most in danger if the big one hit.

    1. All 10 lines in and out of Aberdeen and Hoquiam.

      New comment assignment: why?
      Before you respond, just think about where the Cascadia Subduction Zone is.

      1. Why? Three reasons:

        1, It’s my job. I’m the self-appointed comment section assignment editor.
        B, Because this post is incomplete. Link carries just a fraction of the total public transit users in the trip-county area. It’s like asking, if the big one hits, will the Taco Bell on 4th and Walker survive? He should be asking how all of our transit will hold up, and tell us what routes/areas are most at risk.

      2. OK: Second Hint for you to answer why the 10 most impacted transit routes in the region would be all 10 that serve Aberdeen and Hoquiam:

        Cannon Beach, Oregon March 17th, 1964.

      3. Sam, I previously knew you as a master of the English language, so I’m more than a little disappointed in your lazy writing. “A fraction” of total ridership could 99/100ths. It’s not, but Link is still by far the single transit line with the highest usage in the Puget Sound.

      4. @Yeah, he left out the word small. Pretty sloppy, Sam.

        In any case, Link is about 60,000 a day now, while Metro carries around 400,000. Community Transit and Pierce Transit are about 30,000 a piece (each). If I remember right, Sound Transit buses carry around 30,000 as well.

  8. Does Link have any self-propelled vehicles that can be used in an emergency? Is there a self- propelled vehicle that could push or pull a loaded rail car?


      Our only problem could be if Whistle Workware store out on First South still carried hickory-shirt-striped railroad overalls anymore. Driver’s uniform for most vehicles shown here. Though could still be on the books that driver could only be named “Clancy”, or “Paddy.”

      Credible threat, though: Up to the ‘fifties, tough kids in Chicago used to build “soap box racers”- carts and even cars made of crates, and different kinds of spoked wheels. Also ropes for steering. And race tracks called “the alley.”

      And while mostly gravity powered, could also be fitted with a chain drive. Would hate to imagine coming around the northbound curve by Southcenter and seeing a kid wearing “Our Gang” knickers frantically pedaling toward my train. Worse southbound just north of IDS in the DSTT.

      Thankfully, we’re so far protected by fact that apps give you space monsters instead of trains. Though habit of “Texting While On Rails” could jump the species barrier from the rail side.


  9. I would worry more about Metro. The ETB fleet could be down for months or years. Some hard service choices would have to be made.

    1. 600 vdc overhead wires.
      600 vdc output on the main generator of most locomotives sitting around in SoDo, idled due to landslides.

  10. BNSF tracks between Everett and Seattle are likely blocked in this scenario due to landslides and washed up riprap.

    You would not get most standard railroad equipment to fit on Link, but smaller equipment used for maintenance could.

    New York City uses a small industrial switcher and several standard flat cars for tunnel maintenance. Something like that would work fine, if any could be found nearby.

    200 passengers at an average weight of 200 lbs is 40,000 lbs, which is about the limit of what you want in a standard truck trailer (about 44,000 lbs), so while Link is limited compared to standard freight cars it isn’t quite as limited when compared to moving things by truck.

    Seats in most light rail cars (not sure about Link) are installed with bolts that allow for fairly easy removal and replacement. The doors are reasonably wide, and the platforms are at floor level. Shouldn’t be too difficult to find a few Raymond or similar narrow-aisle pallet jacks for moving pallets of food into the space once the seats are removed.

    Getting power depends on what is available. During one of the big weeks-long ice storms in eastern Canada some time back locomotives were appropriated and the 600 vdc output of the main generator field used to power a number of different things, including 480v resistance heaters in some buildings. Link can’t use 600 vdc, but I think these can also be reconnected to produce 1,200 vdc.

    I don’t know about the resiliency of the electrical system. With the state of the oil storage tanks along Puget Sound and supplies of fuel cutoff, it might not be as big an issue to repair the lines from the Skagit River dams.

    1. We’ll probably see boat traffic come back to just about what it was by the old prints from around 1900. Probably heaviest carrying, most fuel efficient, least infrastructure limited form of transportation.

      Not entirely kidding. Mixed bag for transportation. DSTT will be a storm drain for as long as we need one. But on the other hand, the International District will be a maritime commercial neighborhood like many of the world’s seaports.

      But greatest of all, while the streetcar-murdering concrete bunker couldn’t be seismically destroyed fn the world split in half, it can finally serve good purpose of keeping the rest of the park and its contents from becoming hazards to navigation.

      And: the Sea has many bloodcurdling tales of Vengeance. We’ll call flagship “The George Benson out of Melbourne,” and put ‘er on the Route 44 as shown. And paint ‘er hull green, and her cabin light tan. Aarrrrggh.

      Fer she’ll send many a fat merchant Art Museum to Ivar Haglund’s Locker! And anybody complaining about the trolleywire spoiling their view will walk the plank!


  11. I was riding Amtrak Cascades #508 near Steilacom on the day of the exercise and saw an Army landing craft practice unloading vehicles and supplies at the little beach/boat landing they have there. Fuel for boats will be a problem, but a post-Big One Puget Sound would rely heavily on a new impromptu Mosquito Fleet.

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