The Nineteen Sixty-Four Earthquake: Four and a Half Minutes

Good Friday afternoon, March twenty-seventh, nineteen sixty-four. Five thirty-six in the evening. In the Turnagain Heights neighborhood of Anchorage, people were finishing dinner, finishing errands, coming home from church. The ground began to shake.

It did not stop for four and a half minutes.

The earthquake measured nine point two on the moment magnitude scale, the second-largest ever recorded anywhere on earth. Beneath Prince William Sound, the Pacific Plate had lurched northward under the North American Plate, releasing energy equivalent to the simultaneous detonation of thousands of nuclear weapons. The shaking liquefied the clay soils under Turnagain Heights. Blocks of land up to a mile wide dropped thirty feet. Houses rode the sliding earth into the inlet below. The process has a geological name, lateral spreading, but the people inside those houses experienced it as the ground simply becoming water.

About one hundred fifteen people died in Alaska. Roughly a dozen more died well to the south, most of them in Crescent City, California, killed by tsunamis the earthquake generated. In all, in Alaska and beyond, the toll came to about one hundred thirty-one. The waves reached Hawaii, Japan, and Antarctica.

The quake moved the entire North American tectonic plate. It lifted portions of the Kenai Peninsula eight feet. It dropped portions of Kodiak Island six feet into the sea. It cracked the science of plate tectonics open: geologists who had been skeptical of continental drift theory had, after March twenty-seventh, evidence they could no longer dispute.

Anchorage rebuilt. The neighborhoods that sank were cleared, and the vacant lots became a park. In some places, the bluff edge is still visible, a long irregular scar running through the residential streets above Knik Arm.

The Turnagain Heights slide is the largest urban landslide in recorded American history.