Alaskan Geology and The 1964 Earthquake

Prince William Sound glacier

When speaking of Alaska as a physical place, as a raw and textured landscape replete with massive ranges, volcanoes, and mountain-studded coastline, it’s important to remember that it lies along the Ring of Fire at the boundary of the Pacific and North American tectonic plates. If not for that fact, Alaska would be an entirely different sort of place. It would certainly be less dangerous, and maybe therefore less alluring. Mountain climbers would not flock here to tackle the continent’s highest peaks. Few would find reason to hop a ferry up its vast shores from town to town, exploring the tall fingers of coast on Prince William Sound or the glaciated bays along the Gulf of Alaska. Possibly, the fish would find its rivers less hospitable, and so too would the fishermen. In short, a different breed of wanderers, if any at all, would find themselves dreaming of the inimitable beauty of the Far North and seeking adventure here.

So, because Alaska has turned out to be the sort of place it is, we’d like to delve for a moment into the geologic drama that has shaped it and ultimately brought us here.

Bush plane in Denali

Alaska is essentially an immense mosaic. The accretion of its myriad pieces was and still is driven by plate tectonics, wherein the Pacific plate, like a vast and insistent conveyor belt, thrusts into the North American plate, compressing and folding the lands together to form a slew of valleys and ranges from the Brooks to the Alaskan and Chugach, to name a few. These pieces–once islands, chunks of ocean floor, bits broken off from other lands, and volcanic excretions–came together over the course of hundreds of millions of years of slow collision.


It’s that process that drew Denali, North America’s tallest peak at 20,320 feet, skyward and continues to do so by a millimeter per year. Because it is composed mainly of granite unlike its older sedimentary neighbors (once submerged in ocean waters,) it’s much more resistant to weathering, giving it that striking 18,000-foot relief from base to summit–greater than Everest, K2, or Aconcogua. The Denali region is also rife with volcanic rock, as seen in the variegated slopes of Polychrome Pass.

Denali National Park

Outside of old stones in Denali and elsewhere in the interior, though, Alaska’s volcanism is still very active. Many volcanoes have erupted this year. Volcanoes exist almost exclusively on the coast as a result of subduction, which creates heated magma chambers at the plate’s edge. These same tectonic forces are responsible for earthquakes. Most are small and go unnoticed, but they’re occasionally devastating, like the infamous temblor of half a century ago.

Cordova harbor

At 5:36 PM on March 27, 1964–the evening of Good Friday–a magnitude 9.2 earthquake struck near Valdez, violently shaking all the coastal towns along Prince William Sound and the Kenai Peninsula on up to Anchorage. Everyone in Alaska, and parts of Canada and Washington, felt the earth’s convulsions over an astounding four continuous minutes–minutes, maybe, in which many folks had been contemplating the long, momentous death of one man on a cross. Those four minutes would prove momentous for the south-central Alaskan coast as well, and much was changed so that the shape of things here is now reckoned from them.

The consequences are still evident almost 50 years later, as we saw in several places we visited. Cordova’s Million Dollar Bridge was built in the early 1900s to haul copper on the railway and then converted in the 50s to a highway for visitors to the Childs and Miles glaciers, which flow into the Copper River from the Chugach mountains. It was destroyed in the upheaval and left broken for the next 40 years. Even now, sections of plank remain on the reconstructed portions, and the bridge is somewhat cockeyed where it was torn. Even the terminal face of Child’s glacier, visible from the bridge, is still largely masked by the earthen debris deposited on its southwestern flank.


Orca Adventure Lodge, where we stayed in Cordova, was renovated from an old dorm for workers at the now-defunct Orca Cannery, which once harvested the abundant Razor Clams on the shore. The quake raised the seabed around Cordova six to eight feet, lifting clam beds out of the intertidal zone and crashing the clam industry there. Remnants of the old docks now stand isolated and rotting in the water, an old piece of machinery abandoned on an island of beams. Orcas, once frequent visitors, for the most part stopped entering Orca Inlet, now too shallow for their comfort.

Cordova dock

This sort of thing happened in many other nearby towns. Valdez, which we saw from our ferry back to Whittier, was originally four miles farther east, but it suffered enough damage to warrant relocation, and the native village of Chenega was destroyed entirely, a third of its population lost. A significant section of the Seward Highway on the Turnagain Arm, which we drove to visit Seward and Homer on the Kenai Peninsula, sunk below the high water mark in the tremor and had to be rebuilt in the following years. I don’t know the details of Seward’s damage beyond the expected wrecked buildings, but in Homer the popular Spit sank some eight feet, shrinking to a thin spur. The vegetation there died, leaving the gravel and sand surface that you see today.

Homer Spit

The Great Alaskan Earthquake killed 131 people, most from subsequent tsunamis, and destroyed several villages. It remains the second largest recorded temblor in history, and like all of the strongest ones it was a megathrust earthquake. These occur at plate boundaries, in this case the convergence of the Pacific and North American plates. What happens, essentially, is that the dense Pacific plate subducts beneath those surrounding it in the Ring of Fire. At the Alaskan coast, that means a slow build up of immense pressure as the Pacific compresses into Alaska some six centimeters a year. When that tension finally releases, the earth’s crust shifts and the denser Pacific plate crashes down below. Most of the time, these are subtle shifts, like an animal settling into sleep. But in 1964, the pent-up pressure was so huge that its release was catastrophic, a massive beast disturbed into paroxysmal wakefulness.

Childs Glacier

Cordova, Alaska


Cordova, Alaska is a small fishing community near the mouth of the Copper River, which is on the Prince William Sound.  You’ve probably heard of Copper River Salmon, which is Cordova’s main industry. Nick and I were invited to Cordova by Copper River Marketing and during our five days here, we have learned so much about this unique town.

Cordova is not accessible by land, so Nick and took the Alaska Marine Highway to get here. Our ferry was rather empty, so we were able to weave between seats in order to get amazing views as we traveled the Prince William Sound.  We saw porpoises, otters and a bunch of jellyfish.  Jessyka, one of our hosts, took us from the dock to Orca Adventure Lodge, where we settled in to our room and walked to the shoreline.  While Nick was taking pictures, I waded into the water and after a few moments I noticed that I was about two feet away from a solid wall of salmon.  Much to my delight, the salmon began jumping out of the water, which has been entertaining me all week.


Before dinner, we met the rest of the media tour group. Everybody else is involved with food media: Chef Nathan Lyon, who has a show on PBS (also a JMU Alumni!); His girlfriend/woman of many hats, Sarah Forman; Fred & Rebecca Gerendasy from “Cooking Up a Story”; Ron Ruggless from Nation’s Restaurant News; and Tara Desmond, who authors the food blog “Crumbs on my Keyboard”. This is one fantastic group of people.  We spent an hour drinking beer from Alaskan Brewing Company and getting to know each other. In the lodge’s dining room, Chef Christian Briner whipped up some amazing gourmet vegan cuisine for us and continued to do so all week.


The first adventure our group took part of was a jet boat tour up the Copper River to Childs Glacier and Miles Glacier. Childs Glacier is 12 miles long, 7 miles wide and 300 feet high. From the river, we could only see the 200 foot wall.  The glacier is continuously “calving”, or losing huge slabs of ice, which is very loud and quite the event. While there, Nick and I were lucky enough to see a pretty large slab of ice fall into the river and become an iceberg. Our boat ride led us to the Million Dollar Bridge, which was built in the early 1900s and used to be accessible by car until the road leading to the bridge washed out a couple years ago.  From there, we met Elliot Johnson, who works for the Department of Fish & Wildlife.  His job is to sit by the Copper River all summer and count every single fish that swims by an underwater sonar device.


After our excursion, we met a few fisherman at a cocktail hour.  Speaking with Mike Webber and Katrina Hoffman, I learned about the devastating effects the 1989 Exxon-Valdex Oil Spill had on the town of Cordova.  That event and the 1964 Good Friday Earthquake have shifted the prosperity of the town.  The earthquake – the second most powerful earthquake ever recorded – shifted the entire geography of Cordova, bringing it 6-8 feet higher than before, causing the already shallow waters to be less habitable by marine life. The oil spill greatly affected the life for the animals of Prince William Sound as well as the many fisherman who made a living in the area.

The next day, Nick went fishing with a commercial fisherman.  The amount of salmon in the area is pretty low this time of year, so they didn’t catch many fish, but he was able to see how the operation works.   I explored the area around the lodge, taking pictures of the beautiful scenery.  Cordova is abundant with wild marine life.  During our stay, we spotted plenty of bald eagles, sea otters, starfish, sockeye salmon and giant sea nettles.


In the evening, we met various members of the town of Cordova.  With an average population of 2,500, Cordova feels more like a community than most towns I have ever been in.  It’s common for people to hold multiple important roles.  For example, the town mayor owns the local True Value hardware store and manages the disposal of the European Black Slug, an invasive species in the area.  Everyone we met was extremely intelligent and friendly.

On Friday, Nick toured the fish processing plant and I wandered around the area, taking more pictures.  The tide in Cordova is very extreme, so I had limited time to walk on the shore before it became 6 feet of water.  Our group headed into town.  Nick and I got chai at Orca Books, owned by former town mayor Kelly Weaverling (who is also the highest elected Green Party member).  We strolled around town, eventually to Baja Taco for lunch. Their whole kitchen is inside of an old school bus!


As part of the media tour, we attended the Copper River Wild! Salmon Jam, a festival that raises money to support the local cultural activities.  The festival took place at the Eyak Ski Area, which has beautiful views of the harbor and surrounding mountains.  Nick and I wandered around the ski lift, checking out the fields of Fireweed and picking wild Salmonberries, which are basically giant salmon-colored raspberries.   We also listened to live music and walked around local craft booths, tempted by the Alderwood smoked sea salt.


Saturday was our last day in Cordova.  We were the only two in our media group who opted for a kayaking excursion and met our guide, who turned out to be Kelly Weaverling (bookstore owner, former mayor).  The misty fog that hovered over the glassy water was ethereal and mystical, like a landscape out of a Tolkien novel.  Kelly provided us with stories of John Muir’s time spent in town as well as a brief history of the town.  The highlight of our trip was coming within a couple feet of a sea otter.  Swimming on its back with flippers together in prayer, the otter simply looked at us with curiosity for a few minutes before rolling away.


The rest of our day was relaxing.  We polished off a large vegan pizza from Haborside Pizza, the best New York style pizza I have had outside of New York.  We spent more time (and more money on chai) at Orca Books.  Our “Adult Camp” group enjoyed a final dinner at the Orca Adventure Lodge. Many thanks to go out to Steve Ranney, the owner of the lodge, for organizing our glacier and kayaking tours, outfitting us with proper gear and providing amazing food during our visit.

Cordova, Alaska will always hold a special place in my heart.