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. It had been a relatively warm day in Anchorage – Alaska’s largest city, about 75 miles (120 km) from the quake’s epicenter – and 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. The quake came to be known as the Good Friday Earthquake. According to the U.S. Geological Survey (USGS), it was the biggest earthquake in North America – and second-biggest earthquake in the world as a whole – since modern seismometers came into general use around 1900.
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.
And yet loss of human life was very small. Only 130 people were killed. AEIC 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). (Deborah Byrd)
1964 Good Friday Earthquake
March 27, 1964–Good Friday–seemed like just about any other Good Friday. The temperature was at a warm spring-like 28°F (-2°C). School was closed, many offices closed early, and many people were either home preparing for the weekend festivities or attending Good Friday services. Nobody knew the forces at work approximately 100 miles (161 km) to the east under the mountains surrounding Prince William Sound. Years of plate techtonic activity had been creating pressure along a faultline, pressure that on this day was finally to give way.
At 5:36pm Alaska time, the breaking point finally came. Unable to hold back the pressure, the fault finally slipped. For the first 10 seconds or so, the ground rocked gently. Most people weren’t concerned much, for they had experienced a lot of Alaskan quakes and had learned that they were a part of life here. The gentle rocking increased, and the ground soon began to surge underfoot. Large surface waves were visible, like waves on water. Huge fissures, some up to 30 feet wide, opened and closed in the ground. Anchorage began to crumble as the shaking continued. Houses and buildings twisted and collapsed. Lamp posts fell over. Trees were uprooted. Unable to remain standing due to the seismic waves that were hurling anything and everything into the air, people clung to lamp posts, cars, and each other in an attempt to keep from being knocked down. For almost five minutes, the ground shook. When it was finally over, Anchorage was in ruins, a victim of a massive magnitude 9.2 earthquake, the second largest earthquake ever recorded in world history. (Great Land of Alaska)
On 27 March 1964, the Good Friday Earthquake off Anchorage, Alaska, set in motion local landslide tsunamis, as well as a trans-Pacific wave. The tsunami wave travel time to Crescent City was 4.1 hours after the earthquake, but it only produced localized flooding. The second and third waves to hit Crescent City were both smaller than the first wave, but the fourth wave struck with a height of approximately 20 feet (6.1 m) after having drawn the harbor out nearly dry. The next morning the damage was counted: 289 buildings and businesses had been destroyed; 1000 cars and 25 large fishing vessels crushed; 12 people were confirmed dead, over 100 were injured, and more were missing; 60 blocks had been inundated with 30 city blocks destroyed in total. Although most of the missing were later accounted for, not all were tracked down. Insurance adjusters estimated that the city received more damage from the tsunami on a block-by-block basis than did Anchorage from the initial earthquake.
The tsunami raced down the U.S. West Coast with more deaths and destruction, but no location was hit as hard. Crescent City bore the brunt, due to its offshore geography, position relative to the earthquake’s strike-line, underwater contours such as the Cobb Seamount, and the position of rivers near the city. Although houses, buildings, and infrastructure were later rebuilt, years passed before the city recovered from the devastation to lives, property, and its economy.
Debrah Byrd Earthsky News,
Great Land of Alaska