The Really Big One; The Feared Cascadia 9.0 Earthquake

This video was solely sponsored by the YouTube channel, EarthquakeSim. Be sure to subscribe to his channel at youtube.com/@EarthquakeSim, where he makes numerous videos revolving around earthquake damage simulations and earthquake education! This video took 3 days to make, so I hope that you appreciated it.

My sister in law lives in Victoria. I was told never bring up the conversation of earthquakes. I don't understand why someone would want to live there if they were so afraid.

There is a Japanese painting that shows a tsunami that came out of nowhere: it was caused by the 1700 quake. There is a ghost forest at Nisqually, Washington, that was created then also.

The spookiest part of this is how the 1700 quake was only confirmed via Japanese "orphan tsunami" records, Native oral accounts, and eventually studies of the coastal "ghost forests". It's like the analog of blind people finding an elephant.

Thanks for using my 3D earthquake simulations and for spreading awareness about this topic! The Big One expected on the San Andreas fault would affect an area 10 times smaller, just to put it in perspective. The potential impact is staggering, and it’s clear that understanding and preparing for this event is crucial. Thanks for shedding light on such an important issue!

Most of Oregon coast population is in the worst places for tsunami. And everywhere geologists look, they find evidence of tsunamis.

As an Oregon resident, I have visited Neskowin beach several times. The last time I was there I timed how long it would take to briskly walk to safety in the event of a future megathrust earthquake. It took me, an able-bodied geologist 15 minutes to get to the highway without trespassing over private property. Not even considering likely subsidence and liquefaction, I found 15 minutes to escape the tsunamis too long and haven't been back since.

You mentioned the difference between a normal wave and a tsunami wave. About 35 years ago, while living in Japan for a year, I was on the beach, walking directly at the water's edge. There were normal waves coming in all the time, until suddenly a different looking wave appeared. It was not very high; later I learned that this tsunami wave had a height of 15 cm or 6 inches. It pulled me off my feet and started dragging me out to sea. Only because the water was not very deep was I able to dig my hands into the sand, remain at the beach and ride out this little wave. I was very surprised and rather impressed.

I live in the Phoenix area. The initial disaster would be bad enough, but how about all the various items that come into the West Coast that would NOT be available for months and possibly years while the Ports are being reconstructed? This type of disaster would really adversely affect the entire USA.

I think the casualty estimate of 65k is a huge underestimation. Looking at how poorly (in a seismic sense) buildings are constructed and how few escape routes, often over bridges that are not built to seismic code, there are, this figure would be in the 6 digits at least imo.

What I love about your content is that you cover topics with enough details to get the point across while being succinct in your delivery. No wasted time or words on baseless conjecture or fumbled words. You don't repeat things unnecessarily and your videos are digestible in size. I know longer videos are hard, and I wanted to thank you for your time and effort. Your one of my favorite channels because of how you deliver the information.

I'll never get tired of having this existential fear, periodically reinforced!

12:35 That sign is fantastic. The artist should be proud. "I need you to convey the terror of inevitable death in a stick figure." Captured.

I grew up on the Washington Coast. A beautiful place with incredible wild shoreline beaches. I drove by the Copalis Ghost Forest every day for years while I lived there. BTW- Copalis is pronounced with a long “A” sound, as in Co- pay- lis. My last job there was helping install tsunami warning sirens in the city where I worked and lived. I retired to an inland area, where the weather was warmer and the rain was less. But I still love my PNW- the most beautiful place on earth!

San Andreas Fault: "I'm about to let off the 'Big One' very soon." Cascadia Subduction Zone: "Hold my fault line." Glad to see a video on this topic.

@GeologyHub I think this is one of the more comprehensive videos out there of what will happen. But as someone who lives on the Washington Coast and has been heavily involved in the Cascadia Earthquake preparedness, some things to note: 1. the coastal land subsidence from 1700 was around 10 feet, and instead of just being along the coast, the subsidence continued inland for 50 or more miles but at a gradient, i.e. at the coast it dropped 10 feet, 10 miles inland it dropped 8 feet, 40 miles inland it dropped 3 or 2 feet, and 50 miles of more it might drop a foot or less. This is because the uplift that occurs between earthquakes extends inland at a decreasing rate as well. 2. The following names are pronounced: Co-pail-less, Say-lish, Will-lamb-et, Malt-gnome-muh, 3. The vast majority of cities in the Pacific northwest are located on highly liquifiable soils, especially along the coast. It's likely that more than 100,000 structures, even those built to more modern standards, are at risk of collapse. Further, many of our highways are built over highly liquifiable soils and most of our bridge foundations are not built to bedrock but have foundations resting in silt and mud, meaning they will absolutely collapse, cutting off most viable evacuation routes. 4. Many coastal communities, such as Seaside or Westport, have at most 15 minutes before the first tsunami waves arrive. 5. The latest Washington DNR modeling suggests Tsunami heights along Oregon and Washington ranging from 50 to 100 feet on average, with some specific locations reaching upwards of 150 feet or more. 6. Washington DNR modeling also indicates Tsunami waves of up to 30 feet could continue hitting the coastline up to 12 hours after the earthquake, and large swaths of the coastline will be permanently submerged by up to 15 feet of subsidence. 7. The length of shaking could last anywhere from 8 to 11 minutes, depending on how much of the 600+ mile long fault line ruptures. Recent studies suggest the rupture could propagate from north to south or south to north, and this propagation takes time, it's not instantaneous, so this greatly increases the length of shaking felt by the region. 8. The fatality estimate you show is laughably small for such a massive disaster. We are completely unprepared for such a colossal multi-region disaster, and based on the Federal Government's historic lackluster responses to much smaller regional natural disasters, including hurricanes, it's highly likely it will take many months for our completely overwhelmed federal and state governments to send any sort of substantial help to the most affected areas. Many, many people will die simply because there will be no functioning hospitals or emergency crews to rescue them, and injuries that are usually non-life threatening will become deadly without proper medication. Disease and famine are also likely to kill many in areas without proper supplies of food and contaminated water. 9. Likewise, the cost estimate of this is probably much closer to the trillion-dollar mark.... quite simply there won't be a single structure in the Pacific Northwest, mostly west of the Cascade Mountains, that will not be damaged in some way. You're looking at fully replacing probably 70% of the region's infrastructure (ports, highways, roads, bridges, railroads, dams, sewer, gas, electric, etc.), and probably 60% of buildings, and the remaining percentages will need various levels of repair. This WILL be the costliest natural disaster not only in the US, but possibly the world, especially when you factor in the tsunami damage from the overseas countries impacted by this. 10. One thing you should mention is that most of the Pacific Northwest's major hydroelectric dams are more than 50 years old and were not built to withstand such a large earthquake, and many of these will likely fail during or immediately after the earthquake, especially the large earthen dams. The catastrophic flooding resulting from these failures alone could result in tens of thousands of casualties downstream.

I actually did a project on this in one of my geophysics classes. The danger isnt just the subduction zone causing the mega-thrust, but also the DOZENS (or more) Strike-Slip fault lines in the areas from Olympia to Bremerton also doing a sympathetic release from the megathrust. The total energy release if just half of those faults go was nightmare inducing, especially since almost ALL of my Dad's side of the family lives west of the Cascade range. Needless to say, this was 8 years ago and I have made sure that my Dad and stepmom now both have a 5-minute escape bag, rifle, ammo, and water purification stuff ready to go and he knows that the second he gets that alert they get in their little Lexus SUV with the stuff and FOOT TO THE FLOOR up to higher ground.

As an Oregonian watching this video, I can say the only part that brought me comfort is that I don't drive a Mustang.

Fun fact: we also call this ‘the big one’ in the pnw! Great work as always! I would love if you could look at the origin of the Oregon table rocks

Native Americans keep oral accounts and stories of what happened, there was a rather old National Geographic documentary that looked into the Banda Aceh tsunami and mentioned this Cascadian megathrust earthquake....