The Cascadia Disaster

In this article, Connor will go into detail about "The Big One" megathrust quake, and what should be done to minimize the catastrophic damage.

THE CASCADIA DISASTER

Written by Connor Upshaw

For many years now, rumors have spread in Southern Oregon about the dreaded “Big One,” a massive earthquake that could strike at any moment. It has long been known that such a quake would devastate the entire Oregon coast, from Grants Pass to Portland, and that it would cause vast death and destruction. The Turkey-Syria earthquake of Feb. 2023 showed us the nearly unimaginable devastation that even a magnitude 7.8 earthquake can cause. The Cascadia Subduction Zone, which spans much of Southern Oregon and into Canada, has the potential for a massive magnitude 9.0 earthquake. This raises the question: is Oregon prepared for the dreaded “Big One,” and what is being done to get it there? 

Shows the different areas which would be affected by the Cascadia quake. The redder colors are at higher risk, while green is the lowest risk. Taken from the Oregon Resilience Plan. 

From the Turkey-Syria quake, an image of the devastation. Taken from a Live Science article. 

The Cascadia Subduction Zone in Oregon could have a similar impact as the East Anatolian Fault Zone in Turkey and Syria. The Middle Eastern nations will long remember Feb. 2023 as the month their countries fell to pieces. According to an AP News article, the Turkey-Syria Earthquake is one of the most devastating earthquakes in modern history, resulting in over 50,000 deaths and billions in damages. Huge parts of cities were leveled and reduced to rubble. Over twenty million people were affected in an earthquake zone that spans two countries. The question that was thrown at the governments of both nations is: “How could this even happen?” As they uncovered more and more bodies under the debris, the negligence of both governments regarding earthquake prevention has been revealed. Building construction was not up to earthquake standards of retrofitting, so they collapsed. What many do not realize is how this negligence is present in many other developed nations, including the United States. 

Earthquake retrofitting is the process of reinforcing buildings and structures in order to protect from destructive quakes. It is often expensive, depending on the amount of area being covered, so it is difficult for many cities to retrofit every building with landowner permission. Retrofitting is essential in areas susceptible to earthquakes, one of which is the Cascadia Subduction Zone here in Oregon, as it is the best way to ensure minimal damage. For a standard 2,000 square foot home, it can cost anywhere from $4,000 to $10,000, this article from a Real Estate Website states. Large buildings can cost far more than this. Many homeowners and businesses refuse to retrofit in the first place because of high costs. 

The last time that a major earthquake occurred in the Cascadia Subduction Zone was in 1700, when a 9.0 magnitude quake hit the Oregon coast. This massive quake was known as a megathrust quake. This event resulted in a tsunami that reached as far as the coast of Japan. While there have been some minor quakes since then, there has not been another large one in over three hundred years. The Oregon website states that estimates show a 37% chance of a magnitude seven, or higher, earthquake within the next fifty years. While this may not seem like a significant worry, that is still a pretty high number for something that could be both hard to predict and could kill thousands within hours. 

One remnant of the 1700 quake is the Neskowin Ghost Forest of Tillamook County. They are a large group of tree trunks, half submerged underwater. It is believed to have been lowered from the rest of the forest during the last Cascadia megathrust quake. Image from Flickr. 

Back on retrofitting, an article from KOIN News compares the Big One to the 2011 earthquake in Japan. In it, Professor Chris Goldfinger, a seismologist who lived through the Japan quake, claims that “damage to structures was minimal.” However, “Portland, and most of the Pacific Northwest, is not ready for it.” In Japan, the government retrofitted nearly every building to endure a 9.0 earthquake. In comparison, Portland alone has over 1,600 buildings without proper retrofitting. The issue is that landowners refuse to retrofit because of the high costs. It is cheaper to construct and reinforce new buildings than try and retrofit those built in the '90s and before. Pre-1994, earthquake regulations were essentially nonexistent; now, new buildings are required to be structurally sound. Goldfinger states that the damage in Portland “would be much like Syria,” which would mean mass destruction of buildings and people buried under the rubble. It would be a disaster of terrifying proportion, and it would not just affect Portland. Grants Pass, and the entire coast of Oregon, would be devastated by an earthquake that has been building up for 300 years. The following tsunami would sweep over entire coastal cities, many of which are directly in the tsunami inundation zone.                                                                         

While much of Oregon, Washington, and Canada would be affected by the megathrust quake, the Portland area along the Willamette and Columbia rivers would be most impacted. Not only is it the most densely populated region in the state, but the area is also at huge risk of a process called liquefaction. Liquefaction is a process which, in the case of a large quake, “can cause sandy soil to behave like a liquid,” according to a KGW article. This can result in buildings, trees and cars sinking into the ground, which can be incredibly dangerous for people trapped in the area. Portland State Professor Scott Burns stated that “liquefaction will happen in the event of a magnitude 8 or higher Cascadia quake.” Being in one of the most dangerous sections of the megathrust quake zone, an earthquake of this magnitude is very likely to occur at some point. 

This image is a visual comparison between the same buildings on stable vs liquified soil. Image from Shutterstock.

These are some of the oil tanks along the Willamette and Columbia rivers. Image from the Sierra Club website. 

One of the worst impacts of the Cascadia disaster would be the destruction of the many oil tanks lining both the Willamette and Columbia rivers. These tanks are not built to modern earthquake standards, and many of them would spill into the water. This would be an ecological disaster the likes of which Oregon has never seen, devastating ecosystems across the state. It would be one of the worst oil spills in history. To combat this, many in the state have petitioned the Oregon Treasury to depart from, or divest, from a variety of oil and fossil fuel agreements. Groups such as the Grassroots Coalition Divest Oregon argue that Oregon has always been known for its beautiful environment, and the many agreements between fossil fuel companies and the Treasury go directly counter to the state's identity. Some progress has been made by these groups, with Treasurer Tobias Reed promising to make a plan by 2024. Even with this progress, it is advancing at a snail's pace. 

Oregon is not entirely unprepared to deal with a potential earthquake. The Oregon Resilience Plan (ORP) is aimed at combating both the quake and the following tsunami, and goes into over 300 pages detailing the methods Oregon should use to minimize damages. The ORP, released in 2013, acknowledges how unprepared the Beaver State is for a large quake. It is several times less prepared than countries such as Chile and Japan, as of a 2012 graph. Therefore, the plan goes into detail about what must be done for Oregon to be at the same level of preparedness as these nations. First, the government should invest effort to retrofit all vulnerable buildings. Modern building plans are required to incorporate quake-resistant elements, though only about 20% of older buildings have been retrofitted. Aside from this, the many factors of each individual city should be considered through the lens of what would matter most in an earthquake. Bridges and dams may collapse, potentially creating barriers to evacuation. There must be plans made to evacuate people as efficiently as possible. Citizens and businesses should prepare for the possibility of being trapped in place for several days. This preparation could take the form of stocked up food, water, and first aid. While Oregon has implemented many of the ORP’s recommendations, its structures and citizens are widely unprepared for a massive earthquake and tsunami.

This resilience triangle shows the levels of earthquake resilience of Chile, Japan and Oregon. Smaller and greener triangles are more resilient, while larger and redder triangles are less resilient. Oregon is depicted as many times less earthquake resistant than Chile and Japan. From the Oregon Resilience Plan.

The Big One presents a real threat to the people of Oregon, always looming on the horizon. With the catastrophe that was the Turkey-Syria earthquake, the state of Oregon would benefit from doing everything possible to avoid a similar outcome. Many positive steps have been taken to strengthen the Beaver State’s defenses, but it is still far behind other earthquake-prone states and countries.