Today in science: Great Alaska earthquake

The earthquake – centered in Prince William Sound off the coast of south-central Alaska – was the most powerful yet recorded in North America at magnitude 9.2.

March 27, 1964. On this date, at 5:36 p.m. local time, a 9.2 magnitude earthquake struck in the Prince William Sound region of Alaska, causing extensive initial damage and a subsequent tsunami. The quake came to be known as Great Alaska Earthquake, or sometimes the Good Friday Earthquake. According to the U.S. Geological Survey (USGS), it was the biggest earthquake recorded in North America since modern seismometers came into general use around 1900.

It had been a relatively warm day in Anchorage, Alaska’s largest city, about 75 miles (120 km) from the quake’s epicenter. Schools had been closed for Good Friday, along with many offices. In Anchorage, dozens of blocks of buildings were leveled or heavily damaged.

The city of Valdez, closest to the epicenter, was completely destroyed.

Damage to Fourth Avenue in Anchorage, Alaska, caused by the Good Friday Earthquake. The sidewalk on the left started out at the level of the street on the right. Image via Wikimedia Commons.

The earthquake shook the land for nearly four minutes and caused many natural changes. The Latouche Island area, for example, moved to the southeast by nearly 60 feet (nearly 20 meters), according to the Alaska Earthquake Information Center (AEIC).

USGS now estimates the March 27, 1964 earthquake and tsunami caused $311 million in damages across the state of Alaska.

During the 1964 Good Friday Earthquake in Alaska, both human and natural areas sustained damage. This image is from the Turnagain Heights neighborhood of Anchorage, Alaska. Image via NOAA/ Wikimedia Commons.

Landslide damage in the Turnagain Heights neighborhood of Anchorage, Alaska. Image via USGS/ Wikimedia Commons.

And yet loss of human life was very small. Only 130 people were killed. The UAF Alaska Earthquake Center said the low death rate was:

… due to low population density, the time of day and the fact that it was a holiday, and the type of material used to construct many buildings (wood).

View larger. | Map of southern Alaska showing the epicenter of the 1964 Good Friday Earthquake (red star), via USGS.

The 1964 Great Alaska Earthquake didn’t come close to the loss of life from two slightly smaller and more recent quakes: the December 26, 2004 Indian Ocean 9.1-magnitude earthquake and tsunami (third-largest earthquake recorded on a seismograph, with over 230,000 people in 14 countries killed) and the March 11, 2011 9.0-magnitude earthquake in Japan (fifth-largest earthquake recorded on a seismograph, with nearly 16,000 deaths).

In 1964, Alaska was sparsely populated. Today’s Alaska has a larger human population. If and when a similar quake strikes again, the death toll might be higher.

Click here for a good account of the 1964 Alaska earthquake.

Click here for more photos of the 1964 Alaska earthquake.

The waterfront in Seward, Alaska, a few months after the 1964 Good Friday earthquake. Image via USGS/ Wikimedia Commons.

Bottom line: On March 27, 1964, the biggest earthquake known to have struck in the United States struck in Alaska. It is now called the Great Alaska Earthquake, or Good Friday Earthquake. The death toll was low, but damage to both human structures and natural areas was high.