Q&A: Oregon Earthquake Expert Responds To Audience Questions

OPB invited Jay Wilson, chairman of Oregon Seismic Safety Policy Advisory Commission (OSSPAC), to answer questions from our audience about a Cascadia Subduction magnitude earthquake. Wilson's also an emergency manager with Clackamas County. Here are some of the questions people sent in.

Coping within the neighborhood and immediate community

Question: We live next to power lines. Any advice?

Answer: The main thing is the same advice we give during windstorms: to avoid power lines if they come down, to anticipate that they may be damaged or a hazard, and certainly to plan for being without power - as all of us should - in the days and weeks following a big earthquake.

Question: What are the biggest impediments to long-term reconstruction of utilities, roads, and housing?

Answer: The Oregon Resilience Plan identified the interdependencies between roads, power, electricity, as being the biggest issue that we need to focus on. The relationship between all of these means that we can't fix a single sector unless we're fixing them all in unison, which means there is a great deal of complexity in this problem and how we approach this. Any way that we can improve the seismic safety of our power grids, our road networks ahead of time, means less coordination to repair these systems, and a better ability to respond to critical areas.

Question: I have pets with medications and prescription diet needs. Should I plan for a longer service interruption with their needs?

Answer: Pets are a vital aspect of our families. People make decisions affecting personal safety based on their ability to account for their pets' welfare. So if your pet has medical needs, I would say any ability you have to build a reserve for at least several weeks out would be helpful. We certainly encourage that, when it is possible, for people to have a reserve of their own medications as well.

Question: How are low-income folks in apartments and shared housing going store two weeks of food and supplies?

Answer: If your own dwelling has space limitations, maybe there is a way to partner with a neighbor, to have a shared space in a nearby garage or tool shed. I've heard of some people having more robust lock-down garbage cans that are tied off or fixed outside, as a holding area for these types of things, too. I certainly encourage people to be creative.
For homes that have not been retrofitted, it may be important to consider storing your supplies outside of the house, for if your house is damaged and cannot be occupied.

Question: Is there anything people who don’t own a car should think about during a big quake?

Answer: Having a car may or may not be an asset immediately following the earthquake. We fully expect many bridges and roads to be damaged and impassible. We also expect there are going to be limitations on liquid fuel that will mean prioritizing and rationing for a period of time before many of our systems come back up again. Walking or having a bicycle may be a very viable option for getting around, as opposed to having an over-reliance on cars.

The coast and the tsunami region

Question: At the northern coast where we will be cut off from other communities, how do we survive the extreme cold weather and rain? I feel our barrels are not adequate?

Answer: I think barrels means caches? I'm aware of a number of communities that have been storing supplies, especially outside of tsunami inundation zones. You are correct, if the earthquake and tsunami happen in the middle of winter, people who have evacuated will then be exposed for a number of days - at least - to harsh weather conditions. It is critical that their emergency supplies include provisions for harsh weather, like tents and tarps and warm clothing.

Question: Logistically, how are survivors going to be evacuated then housed? Will they be housed outside the primary impact zone? What does the process of returning look like?

Answer: Based on what we've seen in Japan, the tsunami impact zone will likely not be able to be inhabited for months, if not years. So we expect that residents that live in that evacuation zone will need to be sheltered and then transitioned into emergency housing.

Unfortunately, Oregon is behind on having a statewide-scale plan for tens of thousands of people. There's legislation proposed for what we're calling a "mass displacement event." We're hoping to create a two-year project for stakeholder input, to develop plans and capacity to deal with that.

Question: Any lessons learned from Japan as to how to get people to evacuate from an incoming tsunami rather than go to the coast to observe it?

Answer: We typically see people who have what I call a "fatal curiosity" about tsunami events, who head toward the coast rather than away from it. Emergency officials can't say enough to discourage people from becoming part of the problem.

In Japan, people had to go to even higher ground than they had prepared for, because the tsunami was so much worse than they expected. Here in Oregon, we evacuate for the worst-case scenario tsunami. The best thing to do it get completely out of the zone. If you have any contact with the water, odds are you'll be killed rather than injured.

Portland and the Willamette Valley

Question: Is here expected to be any time in between the subduction event and the earthquake hitting Portland, or is it going to be without warning?

Answer: We expect that at the onset of a Cascadia event on the offshore fault, it will take seconds for the ground waves to reach the I-5 corridor and Portland from their source, but at this time we still don't have an adequate way to detect and notify people of their approach.

For the most part, earthquakes are considered a "no notice" event. Perhaps in the future, we will be able to use technology similar to Japan and Mexico to provide a buffer of a few seconds to help people take immediate precautionary measures that may ensure greater safety - if that means stopping a train, or an elevator, or a drawbridge.

Question: In the Portland area, around Willamette River, what elevations are at risk of tsunami damage by a wave coming up the Columbia?

Answer: Thanks for this question. It comes up a lot. I would like to assure everyone that the tsunami researchers in Oregon expect the impact of the tsunami shouldn't reach much further than around Astoria, mainly because tsunami waves typically last around 20 minutes to 30 minutes before they withdraw back into the ocean, so there won't be a continual push up the Columbia River. Portland and the Willamette River are far from any tsunami harm.

Question: I live in Keizer. Will tsunamis come up the rivers and cause inland flooding?

Answer: The tsunami wouldn't reach Portland. It certainly wouldn't go past Willamette Falls and go further upstream toward Keizer.

Question: My question is about flooding. Will the Eugene, River Road area have flooding from the rivers? Will the dams hold?

Answer: Questions about dam safety come up every time in this discussion. We've had concerns raised form Eugene from our statewide seismic commission. I'm not a dam safety expert. I will defer to the state's department of water resources. They have a dam safety officer, to address the level of design and capacity for any given dam in this state. But the risk of dams being affect by this earthquake is a reality.

Question: I'd like to learn about emergency planning as it relates to folks who work on the west side but live on the east side of Portland. I've made a lot of progress on preparedness at home, but I spend at least half of my days across the river. Aren't most of the bridges predicted to go down?

Answer: Sorry to say, the majority of Portland's bridges are under-designed for this earthquake. Yes, people making plans for their families and dependents should factor that there is a likelihood they will be separated by a broken bridge. Having communication plans and contingencies for not being able to return to home or to work, those are realities people should be discussing openly with their families or neighbors, so you have some backup. What we've told people historically is to have a contact person outside of the immediate area - maybe a family member in another state. Often, the phone networks going out of the area have more capacity than the local phone networks. If people can quickly contact this designated person to report that they are OK, that person can become a focal point for relaying information within the family network.

East of the Cascades

Question: How big will the megaquake be in central and eastern Oregon?

Answer: The earthquake will be felt east of the Cascades, but we expect strong shaking to occur inland to the foothills of the western edge of the Cascades, and the strongest shaking to occur on the coast.

Question: Do these people still need an emergency kit?

Answer: Oh, sure. the thing about a magnitude 9.0 earthquake is that even if the shaking may be considerable, the duration-- which may last for several minutes--  creates compounding effects on buildings and structures, like flexing a paper clip until it breaks. So the kinds of earthquakes that typically occur in California last for 10s of seconds. Our Cascadia earthquake, like in Japan, will probably produce three to four minutes of shaking - and all of Douglas County will feel some degree of that duration.