THE 1964 ALASKA EARTHQUAKE

The 1964 Alaska Earthquake occurred on Good Friday, March 27th. Across south-central Alaska, ground fissures, collapsing buildings, and tsunamis directly caused about 131 deaths. The Alaska Earthquake was a subduction zone earthquake, caused by an oceanic plate sinking under a continental plate. Various sources indicate that these 131 people died as a result of the earthquake: 9 during the earthquake itself, 106 from subsequent tsunamis in Alaska and 16 from tsunamis in Oregon and California. Property damage was estimated at over $300 million ($2.06 billion in current U.S. dollars).

It had a magnitude of 9.4, lasting nearly five minutes, and was the most powerful recorded earthquake in U.S. and North American history and the second most powerful ever measured by seismograph. The epicenter of the earthquake was 78 miles east of Anchorage and 40 miles west of Valdez. The focus occurred at a depth of approximately 15.5 miles.

Ground fissures and failures caused major structural damage in several communities, much damage to property and several landslides. Anchorage sustained great destruction or damage to many houses, buildings, and infrastructure (paved streets, sidewalks, water and sewer mains, electrical systems, and other man-made equipment). Two hundred miles southwest, some areas near Kodiak were permanently raised by 30 feet. East of Anchorage, areas around the head of the body of water known as Turnagain Arm near Portage dropped 8 feet, requiring reconstruction and fill to raise the Seward Highway above the new high tidemark.

Ocean floor shifts created large tsunamis (up to 70 feet in height), which resulted in many of the deaths and much of the property damage. Large rockslides were also created, which resulted in great property damage.

In Prince William Sound, a 27-foot tsunami destroyed the village of Chenega, killing 23 of the 68 people who then lived there; survivors out-ran the wave, climbing to high ground. Post-quake tsunamis severely affected Valdez, Whittier, Seward, Kodiak, and other Alaskan communities, as well as people and property in British Columbia, Oregon, and California. Tsunamis also caused damage in Hawaii and Japan!