Every year the Pacific tectonic plate barges roughly 2 in. into, and under, the North American plate near southern Alaska. Under intense pressure from the friction, the crust bends and strains until it eventually snaps back into place, as it did that March evening. In downtown Anchorage, the quake caused the streets to become asphalt waves, bouncing cars into the air. Parts of the city dropped as much as 30 ft., bringing the Denali Theater marquee on Fourth Avenue to sidewalk level. One block over, the concrete facade of the new J.C. Penney crashed into the sidewalk, killing a crouching pedestrian and a passing driver. At the airport, the control tower toppled over and killed an air traffic controller.
The ground in the Turnagain Heights subdivision simultaneously sank and surged up. "Our whole lawn broke up into chunks of dirt, rock, snow and ice," Turnagain resident Tay Pryor Thomas wrote in National Geographic shortly after the quake. "We were left on a wildly bucking slab; suddenly it tilted sharply, and we had to hang on to keep from slipping into a yawning chasm."
But what claimed 115 of the 131 lives that day wasn't the earthquake itself. It was the tsunami waves that screamed across Prince William Sound and down the Pacific Ocean. The quake had caused several underwater landslides that, in turn, displaced vast amounts of water. The great volume of water that was forced out to sea returned just as quickly, in the form of giant waves that geologists call local tsunamis.
"I was in my house in Cordova eating dinner when the quake struck," recalls Pete Corson, then a U.S. Coast Guard lieutenant assigned to the cutter Sedge. "Our house came almost completely off the foundation. I ran down to the dock and it had split in half and was heaving back and forth. We had to wait until the gap closed before jumping across it to get to the Sedge." Corson brought his wife and three young sons with him as he boarded the cutter. Soon, reports began to crackle over the ship's radio: "The village of Chenega is completely wiped out by a tidal wave. There are many injuries ... only one house left standing." The Sedge was in "Charlie status," with its engines disassembled, and the crew scrambled to get her underway.
Forty-five miles north of Cordova, in Valdez, the 400-ft. freighter SS Chena was in port when the quake hit. Twenty seconds after the initial tremors, 98 million cubic yards of the silty delta slumped away. The massive amount of water displaced came rushing back as a 40-ft. local tsunami, killing more than 30 people as they tried to flee.
"I saw people running -- it was just ghastly," wrote Merrill Stewart, captain of the Chena, which keeled over as the water ran out of the inlet. "They were just engulfed by buildings, water, mud and everything." The Chena, remarkably, was able to right itself and radio this message: "The town of Valdez, Alaska, just burst into flames. The whole dock is afire ..."
In nearby Shoup Bay, the local tsunami reached 200 ft. in height and destroyed a remote cabin. Thirteen people were killed in Whittier as three local tsunamis, the last one 42 ft. high, crashed into town. And in Chenega, an 89-ft. wave killed 23 of the town's 75 residents.
Similar stories unfolded along Prince William Sound. In Seward, the fuel tanker Alaska Standard was in port loading gasoline and diesel when the quake hit. The dock caught on fire as the harbor shore area slumped into the bay. When the water returned, a 30-ft. tsunami destroyed a fuel tank farm, where oil is stored before being offloaded, setting it ablaze. As the fire spread, more than three dozen fuel-loaded tanks exploded.
A "tectonic tsunami," different from the landslide-generated local tsunamis, was caused as the quake heaved 100,000 square miles of Prince William Sound either up or down. Near Kodiak, the ground surged permanently out of the water by 30 ft., while near Portage it dropped by eight. The displaced water went pulsing down and across the Pacific Ocean and didn't stop until it hit Japan.
Back in Cordova, which had suffered only minor damage, the crew of the Sedge finally got underway and was ordered to Valdez. The cutter was in Cordova's 60-ft. shipping channel when it began to drop.
"Our Fathometer just kept dropping," remembers Pete Corson, who realized the tide was being sucked out of the channel. "It was very strange. It was incredibly dark outside, and these giant snowflakes were falling so it was very hard to see, but we could hear this loud clapping -- which were halibut flapping on the seabed." The Sedge came to rest on the channel bottom and 10 minutes later the water rushed back in. "We rode it out under anchor and then went on our way."
The tsunami continued its inexorable southerly push at 415 mph. For the next 2 hours it rolled down the British Columbia coastline, damaging a logging camp in Shield's Bay and destroying 16 houses in Hot Springs Cove. It did more of the same in Washington state.
In Newport, Ore., around 11 pm, it came ashore at Beverly Beach State Park, where a family of five was camping. The mother and father survived, but all three children were swept away.
At 11:52, the first of four tsunami waves struck Crescent City, Calif., just south of the Oregon border. All 10 deaths, and nearly all of the damage, were a result of the final 15.7-ft. wave that struck at 1:45 am.
"It was like a violent explosion. A thunderous roar mingled with all the confusion. Everywhere we looked, buildings, cars, lumber and boats shifted around like crazy. The whole beachfront moved, changing before our very eyes. By this time, the fire had spread to the Texaco bulk tanks. They started exploding one after another, lighting up the sky," recalled Peggy Coons in The Raging Sea by Dennis Powers.
By the time it got to San Francisco, the wave was just a couple of feet high. It damaged several yachts and did more of the same in Hilo, Hawaii. When it reached Japan it was barely visible, but it was still strong enough to damage pearl farms along the eastern coast.
The Aftermath
After the quake, the State of Alaska and the federal government went to work cleaning up. The U.S. Army Corps of Engineers spent $110 million dollars rebuilding roads and clearing debris in Alaska. The native village of Chenega, which was completely destroyed, was moved to higher ground. Likewise the town of Valdez, which sat at the mouth of a silty glacial drainage, was abandoned and rebuilt a few miles west atop a foundation of solid bedrock.
The structural damage to downtown Anchorage was extensive, but the timing of the earthquake, Good Friday evening, undoubtedly spared many lives. As part of its Advanced National Seismic System, the U.S. Geological Survey has recently outfitted a few buildings with complex motion sensors to understand how they respond to quakes. Because of Anchorage's seismically active location -- Alaska's 5000 to 6000 annual earthquakes are more than occur in the rest of the U.S. combined -- its 20-story Robert Atwood Building is one of the most thoroughly monitored structures in the country.
The building is outfitted with 32 instruments from basement to ceiling to detect the "swaying," "twisting," "rocking" and "drift" that result from seismic waves. Seven boreholes, ranging from the surface to a depth of 200 ft., also contain instruments to monitor seismic activity. "We want to see what designs work, and what kind of damage, often structurally hidden, appears," says Mehmet Celebi, a research engineer with the USGS. "In the two years since it's been instrumented we've had 20 small- to medium-size earthquakes in the area. We're waiting for a large event to see how the building really reacts."
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