Good Friday Earthquake

Good Friday Earthquake

The 1964 Alaska earthquake, the strongest earthquake ever recorded in North America, struck Alaska’s Prince William Sound, about 74 miles southeast of Anchorage. Most of Alaska’s mainland felt the magnitude 9.2 earthquake, which wobbled Seattle’s Space Needle some 1,200 miles away. The earthquake was so powerful it registered in all U.S. states except Connecticut, Rhode Island and Delaware. The quake also led to significant scientific breakthroughs in subduction earthquakes and how to minimize their destruction.

The Earthquake Strikes

At 5:36 p.m. on March 27, 1964—Good Friday—the earth trembled just as many Alaskans were sitting down to dinner.

Eyewitnesses described hearing a crunching, grinding noise as the earth shook. They recalled seeing asphalt roads rise and fall like waves and the ground opening and closing before them, water shooting up through the ensuing cracks.

The violent shaking led to water, sewer and gas line breaks and widespread telephone and electrical failures. It effortlessly toppled telephone poles, buckled railroad tracks, split roads in half, uprooted buildings, cars and docks and tore homes apart. Seismic waves caused the earth to “ring like a bell.”

As bad as the tremors were, the worst was yet to come. The earthquake triggered a swell of devastating tsunamis, landslides and submarine slumps which caused massive property damage and loss of life.

The death toll reached 131 people: 15 died during the initial tremors and the rest in the subsequent tsunamis and landslides.

1964 Alaska Earthquake Changes the Coastline

Four minutes may not seem like a long time, but when it comes to earthquakes, it’s an eternity, and tremors during the Great Alaska Earthquake of 1964 lasted at least four minutes.

Geological surveys taken immediately afterward showed parts of the Alaskan coast sank up to eight feet, other parts rose up to 38 feet and much of the coast moved 50 feet towards the ocean. Coastal forests plunged below sea level and were destroyed by salt water.

Local Tsunamis and Landslides

As the tremors ended, local tsunamis sprung up almost immediately, leaving residents little to no time to flee for higher ground.

A massive tidal wave crushed the small, coastal village of Chenega four minutes after the tremors subsided—the town lost a third of its population. Local tsunamis also caused destruction in Kodiak, Whittier and Seward.

Downtown Anchorage had the most property damage mainly due to immense landslides, one of which dropped the business district nine feet.

In the Turnagain Heights area of Anchorage, soil liquefaction (when the ground behaves like a liquid) triggered a landslide which moved parts of a suburban bluff 2,000 feet into the bay, taking up to 75 homes with it.

The control tower at Anchorage International Airport collapsed, killing an air traffic controller. Part of the of the Million Dollar Bridge at Copper River also crumpled.

Thousands of strong aftershocks continued for weeks after the earthquake, some measuring greater than magnitude 6.2. Reports of residual water sloshing (seiches) came in from the U.S. Gulf Coast and as far away as Australia.

Destruction at Valdez, Alaska

The town of Valdez was originally built on sand and gravel. When the earthquake struck, seismic waves caused soil liquefaction and a portion of the delta slumped into Port Valdez, taking much of the port’s resources, living and otherwise, with it.

The delta slump triggered a local tsunami which destroyed almost anything left standing and ruptured the Union Oil Company’s oil tanks, igniting a massive fire. Valdez was basically leveled.

The largest tsunami wave of the 1964 Alaska Earthquake measured over 200 feet in height and was recorded at Shoup Bay near the Valdez inlet.

Tectonic Tsunami Devastation

In addition to local tsunamis caused by underground landslides, the earthquake triggered an enormous tectonic tidal wave.

After wreaking havoc on southeastern Alaskan coastal towns that had already endured local tsunamis, the tectonic tsunami made its way to British Columbia where it ravaged small villages along the coastline near Vancouver.

The tsunami, which caused massive property damage in Washington, Oregon and California, also claimed four lives in Oregon and 12 in California. The tidal wave had diminished by the time it hit Hawaii and Japan, causing little damage.

Still, the fact that it reached those areas at all is testament to the enormity of the quake.

The Reason the Earthquake Happened

Prior to the 1964 Alaskan earthquake, scientists had limited knowledge of what happens far beneath the earth.

Afterwards, geologists realized subduction zones—areas where two tectonic plates (huge slabs of rock made of the earth’s crust and upper mantle) meet and one bends under the other—played a major role in creating the immense Alaskan quake.

Scientists learned that at the point where the North American Plate overrode the Pacific Plate, it descended into a subduction zone. According to the United States Geological Survey, “The 1964 earthquake was giant because of the large area of the fault that slipped during the earthquake and the large amount of slip, or relative motion, between opposite sides of the earthquake fault.”

During the earthquake, it’s estimated the fault slipped between 30 to 60 feet, an immense shift.

1964: Alaska’s Good Friday Earthquake

On March 27, 1964, a megathrust earthquake struck Alaska, about 15 miles below Prince William Sound, halfway between Anchorage and Valdez. The quake had a moment magnitude of 9.2, making it the second most powerful earthquake ever recorded. The initial quake and subsequent underwater landslides caused numerous tsunamis, which inflicted heavy damage on the coastal towns of Valdez, Whittier, Seward, and Kodiak. Alaska’s biggest city, Anchorage, suffered numerous landslides, destroying city blocks and neighborhoods. An estimated 139 people were killed, most by tsunamis — including 16 deaths on Oregon and California shorelines. The old town site of Valdez was abandoned, with reconstruction taking place on stable ground nearby. This is the fourth of five entries focusing on events of the year 1964 this week (and next Monday). Monday’s entry will feature images of the New York World’s Fair.

  • The rails in this approach to a railroad bridge near the head of Turnagain Arm, southeast of Anchorage, were torn from their ties and buckled laterally by movement of the riverbanks during a massive earthquake on March 27, 1964. The bridge was also compressed and developed a hump from vertical buckling. #

    U.S. Geological Survey

  • A photographer looks over wreckage as smoke rises in the background from burning oil storage tanks in Valdez, Alaska, on March 29, 1964, two days after the earthquake struck. #

    AP Photo

  • Downtown Anchorage, the collapse of Fourth Avenue near C Street, due to a landslide caused by the earthquake. Before the shock, the sidewalk on the left was at street level with the one on the right. #

    U.S. Army

  • The dock area, a tank farm, and railroad facilities in Whittier, Alaska were severely damaged by surge-waves developed by underwater landslides in Passage Canal, on March 27, 1964. The waves inundated the area of darkened ground, where the snow was soiled or removed by the waves. #

    U.S. Geological Survey

  • The waterfront of Seward, Alaska, weeks after the earthquake, looking north. Note the “scalloped” shoreline left by the underwater landslides, the severed tracks in the railroad yard which dangle over the landslide scarp, and the wind row-like heaps of railroad cars and other debris thrown up by the tsunami waves. #

    U.S. Geological Survey

  • Smoke rises high into the Alaska sky from burning oil tanks in Whittier, on March 30, 1964. #

  • The Four Seasons Apartments in Anchorage was a six-story lift-slab reinforced concrete building which collapsed during the earthquake. The building was under construction, but structurally completed, at the time of the quake. #

    U.S. Geological Survey

  • An unidentified man sits at a desk beside hi-fi sets moved to the middle of Fourth Avenue in Anchorage on March 31, 1964. The items were moved from a store that was demolished in the earthquake. #

    AP Photo

  • The marquee of the Denali Theater sits even with the street in Anchorage. The building’s foundation subsided until the marquee came to rest on the sidewalk. #

    U.S. Geological Survey

  • The path of destruction made by the quake in Alaska followed by a tsunami can be seen in this aerial view of Kodiak on March 29, 1964. The wave swept in from the lower left and towards upper right, pushing and smashing everything in its way. #

    AP Photo

  • Chaotic condition of the commercial section of Kodiak following inundation by seismic sea waves. The small boat harbor contained an estimated 160 crab and salmon fishing boats when the waves struck. #

    U.S. Navy/NOAA

  • A view of the destruction of Valdez, Alaska. Thirty-one residents died during the earthquake and subsequent tsunami. Instability and vulnerability to future tsunamis made the old town site too dangerous to rebuild, so the town was relocated several miles west to more stable ground, and rebuilt. #


  • Chaos on the waterfront in Seward, burned-out vehicles and rail cars strewn across the ruined rail yard. #


  • A mother stands watch as her child plays in a puddle of water near her earthquake-shattered home in Kodiak, Alaska in March of 1964. #

    AP Photo/File

  • Tsunami damage and high-water line at Seward. The tsunami waves washed the snow from the lower slopes of the hillsides, and the height of the highest wave is marked by the sharp “snow line” on the hillside behind and just above the rooftop at left center. #

    U.S. Geological Survey

  • The roof of a structure dragged into an Alaskan bay after the 1964 earthquake. #


  • Support columns punched through the deck of the Twentymile River Bridge, as it collapsed during the earthquake, near Turnagain Arm on Cook Inlet. The adjacent steel railroad bridge survived with only minor damage. #

    U.S. Geological Survey

  • Government Hill Elementary School in Anchorage, destroyed by the Government Hill landslide. #

    U.S. Geological Survey

  • In an Anchorage neighborhood, a wooden fence at the toe of the L Street landslide, buckled and shortened by compression. #

    U.S. Geological Survey

  • An Anchorage neighborhood name Turnagain Heights was partially destroyed by a landslide shortly after the earthquake. #

    W.R. Hansen/U.S. Geological Survey

  • The jumbled ground of Turnagain Heights, after the landslide. #


  • Damaged homes in the Turnagain Heights landslide area in Anchorage. #

    U.S. Geological Survey

  • A wider aerial view of the Turnagain Heights landslide. Most of this area is now a park – you can see it today on Google Maps. #

    A. Grantz/U.S. Geological Survey

  • An earthquake-and-landslide-damaged neighborhood in Anchorage, Alaska. #

    AP Photo

  • This highway embankment fissured and spread, cracking down the middle. The road was built on thick deposits of alluvium and tidal estuary mud along Turnagain Arm near Portage. #

    U.S. Geological Survey

  • The village of Portage, at the head of Turnagain Arm, flooded at high tide as a result of 6 feet of tectonic subsidence during the earthquake. #

    U.S. Geological Survey

  • With the city under martial law, soldiers patrol a downtown street in Anchorage, Alaska, on March 28, 1964. In background is the wreckage of the five-story J.C. Penney’s store at Fifth Avenue and D Street. #

    AP Photo

  • Anchorage small business owners clear salvageable items and equipment from their earthquake-ravaged stores on shattered Fourth Avenue, in the aftermath of the quake. #

    AP Photo

  • The head of the L Street landslide in Anchorage. The land on the left side sank 7 to 10 feet in response to 11 feet of horizontal movement of the lower section of the slide. A number of houses were undercut or tilted by subsidence of the graben. Note also the collapsed Four Seasons Apartment Building and the undamaged three-story reinforced concrete frame building behind it, which are on more stable ground. #

    U.S. Geological Survey

  • A man and his wife carry a load of possessions from their earthquake-shattered home in Anchorage, Alaska, on March 31, 1964. #

    AP Photo

  • A fractured city block in Anchorage, Alaska, on March 28, 1964. #

    AP Photo

  • One span of the ‘Million Dollar bridge’ of the defunct Copper River and Northwestern Railroad was dropped into the Copper River by the earthquake. #

    U.S. Geological Survey

  • A fishing boat and buoy, washed ashore by tsunami waves in Seward, Alaska. #


  • A forlorn couple stands on a concrete dock viewing the remains of the Kodiak waterfront on March 29, 1964. #

    AP Photo

  • Trees up to 24 inches in diameter and 100 feet above sea level were broken and splintered by the surge wave generated by an underwater landslide in Port Valdez on Prince William Sound. #

    U.S. Geological Survey

  • This truck was bent around a tree by the surge waves generated by the underwater landslides along the Seward waterfront. The truck was about 32 feet above water level at the time of the earthquake. #

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