Everything Everywhere Daily: History, Science, Geography & More - The 1964 Alaska Earthquake

Episode Date: March 21, 2023

On March 27th, 1964, the second-greatest earthquake in recorded history stuck the state of Alaska.  It was an absolute monster of an earthquake, completely devastating communities, including Alaska��s capital, Anchorage.  The quake was so great that people could feel it 1,200 miles away in Seattle.  Despite its power, the secondary effects of the earthquake might have been even worse. Learn more about the 1964 Alaska earthquake on this episode of Everything Everywhere Daily. Subscribe to the podcast!  https://link.chtbl.com/EverythingEverywhere?sid=ShowNotes -------------------------------- Executive Producer: Charles Daniel Associate Producers: Peter Bennett & Thor Thomsen   Become a supporter on Patreon: https://www.patreon.com/everythingeverywhere Update your podcast app at newpodcastapps.com Discord Server: https://discord.gg/UkRUJFh Instagram: https://www.instagram.com/everythingeverywhere/ Facebook Group: https://www.facebook.com/groups/everythingeverywheredaily Twitter: https://twitter.com/everywheretrip Website: https://everything-everywhere.com/ Learn more about your ad choices. Visit megaphone.fm/adchoices

On March 27, 1964, the second greatest earthquake in recorded history struck the state of Alaska. It was an absolute monster of an earthquake, completely devastating communities, including Alaska's capital Anchorage. The quake was so great that people could feel it 1,200 miles away in Seattle. Despite its power, the secondary effects of the earthquake may have been even worse. Learn more about the 1964 Alaskan Good Friday earthquake on this episode, of everything everywhere daily. Do you ever climb into bed ready to sleep only to have your mind start racing

the moment your head hits the pillow? Thoughts bouncing around, replaying the day or jumping ahead to tomorrow? That is exactly why Catherine Nicolai created Nothing Much Happens. Each episode is a gentle, cozy bedtime story where, well, nothing much happens. No drama, no tension.

Nothing you need to follow closely. Just soft narration, calming repetition, and soothing sensory details designed to help your mind slow down and your body relax. It's not about entertainment, it's about rest. And millions of listeners around the world use it every night to quiet their thoughts and finally fall asleep.

If you've ever struggled to shut your brain off at night, this might be exactly what you've been missing. You can listen to Nothing Much Happens wherever you get your podcasts. Episodes are every Monday and Thursday. The 1964 Alaskan earthquake registered 9.2 on the Richter scale. And I want to reiterate that. It was a 9.2 earthquake on the Richter scale. And before I get into the details of the Alaskan earthquake, I want to do something that I have yet to do on this podcast, which is explain exactly how the Richter scale works because many people aren't aware of exactly what the numbers mean.

The Richter scale is actually called the Richter Magnitude Scale, and the key word here is magnitude. The Richter scale is a logarithmic scale. What this means is that an earthquake that measure, 6.0 isn't twice as powerful as one that measures 3.0, it's actually a thousand times more powerful. The key is measuring orders of magnitude, which is basically measuring the number of digits. To create an analogy, let's make a logarithmic scale for money. If you are a two on this scale, then you have $100, because 100 has two zeros. If you are a four on this scale, then you have $10,000, $1 million, a $6 is $1 million, and a $9 is $1 billion. The Richter scale measures the amplitude of seismic waves generated by an earthquake.

Every point on the Richter scale is a tenfold increase in power. It also so happens that the more powerful the earthquake, the fewer of them there are. Earthquakes below 3.0 happen every day around the world, and they usually can't be felt. There are millions of earthquakes below 3.0 every year. Between 4 and 4.9, you will feel it if you live in the area, but there probably won't be much of any damage. I felt a few of these around the world myself. Earthquakes in this range can be measured by seismographs usually around the world to some degree. From 5 to 5.9, it could damage poorly built buildings, but it probably won't damage modern buildings.

Things might fall off of shelves in this kind of earthquake. There are between 1,000 to 1,500 of these types of earthquakes every year. From 6 to 6.9, it can cause severe damage to poorly constructed buildings near the epicenter and moderate damage to well-built buildings. The 1989 San Francisco earthquake was a 6.9. There are about 100 to 150 of these type of earthquakes every year. From 7 to 7.9, we're starting to get into the realm of serious earthquakes. Depending on the construction quality, entire buildings can be destroyed, and even well-built

buildings may suffer serious damage. The February 2023 earthquake in Turkey and Syria measured 7.8, and the San Francisco earthquake of 1906 measured 7.9. There are only 10 to 20 such earthquakes every year. From 8 to 8.9, we're talking about the very biggest earthquakes. These are truly devastating and also very rare. There might be one of these per year and it's usually in an uninhabited area. Whenever these strike a populated area, you can expect widespread damage. Since seismologists have been measuring earthquakes beginning in the early 20th century, there have been only five which have been measured at 9.0 or greater. A 9.0 earthquake is so great that it doesn't really matter where it takes place.

It's going to do damage to something, somewhere, somehow. An earthquake above 9.0 will pretty much destroy everything at its epicenter. The 2011 earthquake in Japan that wrecked the Fukushima nuclear power plant measured 9.0. The 2004 earthquake in the Indian Ocean that caused the devastating tsunami that killed almost a quarter million people measured 9.1. So when I say that the Alaskan earthquake was a 9.2, and the reason I took all this time explaining earthquake magnitudes, is that 9.2 is a number that you have to respect. The only earthquake ever measured which was greater was the 1960 earthquake in Valdivia, Chile, which measured 9.5. And this is as close to the largest possible earthquake that seismologists think could be created via normal plate tectonic activity. So, what happened in Alaska?

At 5.36 p.m. local time on March 27th, a Good Friday, a megathrust occurred between two tectonic plates. A megathrust is the largest type of earthquake known, and they only occur in subduction zones. It's estimated that the fault move 30 to 60 feet, which is an enormous amount for such a short time in geologic terms. In a previous episode on volcanoes, I talked about the Ring of Fire. The Ring of Fire is a region of tectonic plate subduction around the Pacific Ocean. Southern Alaska lies where the Pacific Ocean Plate goes under the North American Continental Plate. the fault line is responsible for the entire Illusion Island Archipelago. So this type of earthquake couldn't occur along the San Andreas Fault,

which runs along the coast of California as it's not a subduction zone. The earthquake lasted for four minutes and 38 seconds, an eternity in terms of earthquakes. The epicenter of the earthquake was very close to shore, only 12.4 miles or 20 kilometers north of Prince William Sound, but perhaps more importantly, it was only 78 miles or 126 kilometers east of the capital of Anchorage. Those who experienced the earthquake found something which seemed like it was right out of the Bible. Paved roads rose and fell as if they were a slinky. The ground literally opened up in places.

There were vertical displacements of land as large as 38 feet or 12 meters. That means in a spot that was perfectly flat beforehand, in just five, minutes, there was now a cliff. The coastline of Alaska literally changed. Some sections rose and some went underwater. One section moved 50 feet towards the coast. Buildings collapsed everywhere. Gas, water, sewer, and electrical lines were all cut. One of the most pronounced memories that people had of the earthquake was the sound. They claimed that the earth was ringing like a bell, and they were actually hearing the grinding of the tectonic plates. In some place, the ground moved so much that it liquefied.

Liqueification occurs during strong earthquakes on soil that is very loose and has a lot of water. Liqueification is extremely dangerous. Imagine the ground turning into the equivalent of wet sand. In that environment, buildings can collapse, and even cars can sink into the ground. Much of what geologists know about soil liquefaction, in fact, came from the Alaskan earthquake. The most devastating consequence of soil liquefaction was land. landslides. Anchorage was hit by several landslides. The Turnigan neighborhood had 75 homes that were lost in a landslide. Many other neighborhoods and most of downtown Anchorage were also destroyed.

As bad as everything I just described was, that was not the worst part of the earthquake. The worst part was the tsunamis. Valdez, Alaska was built on sand and gravel and suffered severe soil liquefaction. Much of the town of Valdez simply slumped into the Valdez inlet. The land moving into the water then caused a massive localized tsunami. This massive wave in such a small area caused the water to slosh around like it was in a bathtub. One wave reached a height of 220 feet or 67 meters as it washed up on the surrounding mountains. I once went kayaking in Valdez and was astonished when our guide, showed us just how high the water went up the mountain during the tsunami. This was just one of as many

as 20 tsunamis that were caused by the earthquake. There were other localized tsunamis like this one which were caused by landslides. However, there was also one big tsunami that was caused by the thrust of the tectonic plate itself. The coastal towns of Seward and Kodiak were all hit hard. The small village of Chenga lost a third of its population and every building save for the school, was located at 100 feet above sea level. The main tsunami swept down the western coast of North America. Large-scale damage was reported in British Columbia, Washington, Oregon, and California. Four people in Oregon and 12 in California were killed. The tsunami waves were reported as far away as Peru, New Zealand, Japan, and even Antarctica. The final death count from the earthquake was

only 131, which was shockingly low for an earthquake of this size. The lone, the low. The low number was mostly due to the fact that it occurred on holiday in a part of the world with a very low population density. Nine people died directly from the earthquake, and the remaining 122 died from the tsunami. While the population in the area wasn't great, it was the most populated part of Alaska. Most of the communities in the region, which I've mentioned, were totaled. The town of Valdez had to relocate to higher ground. In addition to most of it just sliding into the sea, the oil storage tanks in the town ruptured, causing a massive fire. You won't find a lot of old buildings in anchorage or sewered because of the earthquake. Almost all of the infrastructure had to be rebuilt from

scratch. For weeks after the earthquake, there were aftershocks that plagued the region. On the first day after the earthquake alone, there were 11 aftershocks that measured over 6.0 on the Richter scale. One of the only means of communications after the quake was radio reporter Jeannie Chance of station K-E-N-I. She stayed on the air for 24 hours straight to help coordinate rescue efforts, guide people to emergency shelters, and help survivors find family members. One of the things that came out of the earthquake was a much better understanding of exactly how earthquakes work. For the first time, the phenomenon of soil liqueification was able to be studied closely. And the seismic data from the earthquake also proved the existence of subducting tectonic plates.

In the aftermath of the earthquake, the United States founded the National Tsunami Warning Center, which is headquartered in Palmer, Alaska. The tsunami warning center can now issue tsunami warnings in a matter of minutes, which can save lives all over the world. Likewise, better building codes and locations of relocated buildings and villages improve safety for the day if and when such an event happens again. Earthquakes of the magnitude of the 1964-alaskan quake are extremely rare. It's entirely possible that many of us will never see an earthquake of this strength again. However, it's also possible that one could happen this year. If and when the next one does occur, the impact of it will be mitigated due to the lessons learned in Alaska in 1964.

The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Thor Thomson and Peter Bennett. Today's review comes from listener Darren, who sent me an email. He writes, Everything Everywhere Daily is a super fantastic podcast, always interesting educational and horizon broadening. I discovered it during the pandemic and binge listened until I caught up to every episode. Consistently enlightening and frequently ingenious, the rock and roll episode was no exception and had perhaps the best sly ending yet. Without a time-bending feedback loop and the future invention of the flux capacitor, we wouldn't have rock and roll. Well played. Thanks, Darren. Actually, you can

find a working flux capacitor in the completionist club. And if you should run across it, however, don't touch the settings. We have it dialed into precisely 1.21 gigawatts. Remember, if you leave a review or send me a boostogram, you two can have it right in the show.