Alaska News

In aftermath of giant quake, Anchorage allowed rebuilding in slide-prone Turnagain area

Originally published March 24, 2014

In the aftermath of North America’s biggest earthquake, Alaskans got serious about seismic hazards.

Scientists, planners, government officials and business investors spent years amassing data and rules aimed at ensuring that people and structures would be safe from future quakes.

They mapped out vulnerable spots in earthquake-prone parts of Alaska. They moved the entire city of Valdez, which had been ruined by the quake and the successive tsunamis, to a safer location. They beefed up tsunami warning systems, practiced and drilled for future tsunamis and mapped out evacuation zones. They insisted on earthquake-safe building standards. The wisdom of those standards was confirmed in 2002, when the trans-Alaska pipeline withstood a magnitude-7.9 quake along interior Alaska's Denali fault.

But one post-1964 earthquake-safety policy remains controversial decades later.

Local officials in Anchorage, after hearing input from all sides, agreed to allow rebuilding in some of the most slide-prone areas of Alaska's biggest city. Today, some of Anchorage's most expensive and beautiful homes stand on the bluff above Cook Inlet, one of the areas designated deep red (likeliest to experience earthquake damage) in the Municipality of Anchorage's seismic-hazards map. In some cases, houses have been built atop the ruins of old houses in West Anchorage's Turnagain area that were wrecked in 1964.

Some earthquake experts advised against the rebuilding on the bluff and a few other parts of Anchorage. Among them was John Aho, now chairman of the Alaska Seismic Hazards Safety Commission and one of the experts who helped manage recovery after the 1964 quake.

"I fought against it, but I lost," said Aho, who himself lives in the Turnagain area but inland from the vulnerable site. "I would not, myself, buy a house on the bluff area."

The decision to allow rebuilding there, he said, considered the magnitude of any future earthquake that would be required to cause the ground to undergo liquefaction -- the transformation of solid ground into a collapsing, jelly-like substance.

Chances are, officials at the time figured, it would take at least two full minutes of shaking before any liquefaction occurred, he said. The 1964 earthquake shook for more than four minutes, but a repeat occurrence in the same place and of the same magnitude was considered unlikely, he said.

The decision to allow rebuilding also factored into new building-code standards and the fact that only single-family homes or duplexes would be allowed, he said.

Some recall how dangerous a place West Anchorage was on March 27, 1964.

Chris von Imhof, at the time the new Alaska marketing manager for Scandinavian Airlines, was alone in his airport office when the shaking started. He had to use a chair to break out a window, from which he jumped. "I saw the control tower crumbling right down in front of me," said von Imhof, who became state tourism director and later was the longtime chief executive of Alyeska Resort. He helped pull people from the rubble of the airport's collapsed control tower, though one person died. Many aftershocks followed. That day was so traumatic that whenever von Imhof feels earthquakes, even small shakers, the memories are stirred.

Now he has family and friends living in Turnagain, and he is comfortable with that.

"I'd like to think that it's fairly safe, as long as they put in the right kind of building codes," he said.

There is one prominent swath of deep red on the seismic map where new houses didn't spring up: Earthquake Park is left undeveloped, except as a park, of course. And John Aho said that was a good thing.

Contact Yereth Rosen at yereth@alaskadispatch.com

Sponsored