Quakes, tsunamis remembered



of the Anchorage Daily News

ANCHORAGE, Alaska — NOAA’s National Geophysical Data Center puts the total deaths resulting from the Great Alaska Earthquake of 1964 at 139. Fifteen of them are attributed to falling buildings or crumbling ground during the quake itself. The rest were killed by water.

Thirty-two people died when a wave 30 feet high boiled up in Port Valdez. Similar sized waves took 12 lives in Seward and 15 in Kodiak and its surrounding villages. Another dozen perished when a wall of water 40 feet high smashed into Whittier. In the Prince William Sound village of Chenega, a third of the population — 23 people — was swept away by a 90-foot wave.

Smaller numbers of casualties were reported in settlements across the region, from Cape St. Elias to Port Nellie Juan. One death took place at Shoup Bay on Valdez Arm, where the wave may have splashed 220 feet up the Chugach mountains.

In many places, the ground was still shaking as the water hit.

“We have this picture in our heads that first an earthquake happens, then the tsunami comes,” said Mike West, State Seismologist at the Alaska Earthquake Information Center at the University of Alaska Fairbanks. “But in Alaska’s fjords, something else happens.”

In the second biggest earthquake ever recorded, that “something else” was massive.

“The entire floor of Prince William Sound failed,” said Cindi Preller, Tsunami Program Manager for NOAA Alaska Region. “It was chaos.”

There are different kinds of tsunamis, and the 1964 earthquake set off a variety of them.

One was a general global splashing generated by the magnitude of the quake. The 1964 event was so strong it made the whole world “ring like a bell,” reads a U.S. Geological Survey pamphlet. Vibrations shook the planet for weeks and caused measurable sloshing as far away as Florida.

Shifts in water levels were recorded in 47 states, including land-locked ones. Even in South Africa fluctuations were seen in wells.

One type of tsunami produced by the earthquake, seiche waves, caused no casualties, but were violent enough to sink boats in Louisiana. Seiche action refers to standing waves in enclosed or confined water.

They can be caused in different ways. Those caused by seismic disruptions can occur in places with no direct connection to bodies of water near the source of an earthquake.

Tectonic tsunamis are created directly by the shock of a fracture.

They tend to come in a series of waves rather than a single surge, like the ripples formed when you plunk a rock into a calm pool and the displaced water spreads out in rings.

In an undersea fracture, displacement of the water comes from below. University of Alaska Anchorage geology professor Kristine Crossen said the sudden upthrust at one spot of Prince William Sound was so large it took two minutes for the water to run off it.

“When the ocean bottom is moved, it sets up a wave train,” said Peter Haeussler, U.S. Geological Survey research geologist.

These trains can travel thousands of miles at speeds of 500 miles an hour. In the deep water of the open ocean they seem small. But as they enter shallow water near shore, they grow slower and taller.

In 1964, tectonic waves were generated from two areas in the massive rupture, said Preller. One was near the epicenter, where the quake began, in northern Prince William Sound. The other was near Kodiak, hundreds of miles away.

These waves took lives and leveled buildings from Alaska to California, often with the most lethal kind of wave in the 1964 quake, landslide tsunamis, which happen when the earthquake causes an avalanche.

That’s what happened in Lituya Bay in Glacier Bay National Park on July 9, 1958. Tumbling rock and ice sent up a megatsunami 1,720 feet high, the largest wave in modern times.

The steep, mile-high mountains we see above ground throughout the southern coast of Alaska are mirrored by a similar submarine geography, where slopes can be further encumbered by millions of years of volcanic residue, glacial silt and other muck.

A strong shake can send incalculable tons of material tumbling under water, unseen and undetected until the displaced ocean shoots into the air.

“Those are really devilish,” West said. “And they’re not currently predictable.”

Valdez was founded during the gold rush on glacial fill and alluvial deposits surrounded by precipitous mountains. The ground at the old town site was flat and easy to build on and ran right to the edge of a deep water port.

When the earthquake began, the delta deposits liquified. A mile of waterfront slumped into the bottom of the harbor, pushing water toward the open sea.

A home movie taken from the deck of the freighter Chena, tied to the city dock, shows the 400-foot ship sinking into a giant hole in the water, the bottom of the harbor exposed. Then, with ferocious frothing, the ocean crashes back.

Those on the dock — citizens, curious children and workers — were killed in the first seconds of the quake. Amazingly, the Chena rode out the surge that carried it into the town and left it high and dry — temporarily. New waves hit, some after midnight, and floated it out to sea.

“We think Valdez had two landslipping events,” said Preller — one in Valdez Arm, the other right under the dock.

Most Valdez businesses and half its homes were destroyed. Fuel tanks split open and their contents caught fire, a catastrophe repeated Whittier, Seward and Crescent City.

The fjords and coves throughout Prince William Sound, the area nearest where the quake began, experienced similar underwater landslides causing waves estimated to have splashed as much as 220 feet above sea level. Most of these places had few if any residents.

But there were people in Whittier and Seward, where, as in Valdez, the narrow harbors confined by steep slopes channelized the water into a bore, amplifying the wave action like a giant bathtub.

Arriving right after the quake, or while it was still rumbling, they gave residents no warning and little chance to escape. “The first tsunamis hit two minutes after the earthquake started,” said Preller. The quake lasted 41/2 minutes.

The island of Chenega, southwest of Valdez, is not a dead-end inlet, like Whittier. But it is surrounded by precipitous submarine channels. “Prince William Sound is an environment where the inlets are extremely deep,” said Preller. The underwater valleys had much the same effect as the above-water fjords.

The first wave rose smoothly but with astonishing speed, catching people trying to outrun it, trapping others at home. A second wave struck more violently, smashing every structure in the village except for the school. A third scattered whatever was left.

Survivors huddled by a fire through the night with no way to get word of their plight to the outside world.

People in Kodiak figured the big quake was shaking only their neighborhood.

The first inkling it might be more serious came when they noticed long distance phone service was out.

In the village of Kaguyak on the south end of Kodiak island, however, residents observed the odd swell on the ocean. They began moving away from the shore and sent radio warnings to nearby communities. Warnings picked up elsewhere on the island, alerting the people of Kodiak city 20 minutes before the first wave arrived.

The city’s fire trucks ran their sirens to warn the population. Police went door to door urging evacuation and a line of cars started up Pillar Mountain. The town’s taxis used CB radios to establish an ad hoc communications network.

The first surge came into Kodiak harbor at low tide, about half an hour after the quake. It didn’t reach much past the docks and is thought to have been a landslide tsunami. “It came much sooner than we would have expected from a tectonic tsunami,” said Preller. Most of the affected towns experienced both types of wave, she said.

Thirty minutes later a second wave came into the city, pushing boats into the city streets, floating cars away, wrenching buildings from their foundations and causing walls to collapse. It was not the towering breaker that swept up the Chena in Valdez or wiped out a sawmill and its workers in Whittier, but more on the lines of a large swell.

“Survivors most often describe tsunamis as a rapidly rising tide,” said Haeussler. “They’re like a continuous rise of the ocean that never stops. Often you cannot outrun it. It just overwhelms everything in its path.”

At least three more waves ripped through the town in the next few hours. It’s presumed the highest reached 26 feet above mean low tide. But no one saw it. It came in pitch dark after midnight when most of the population had moved up the hill. Kodiak fatalities tended to come not from people on land, but from those who were in fishing boats caught in the surge.

Kodiak was luckier than Crescent City, Calif. Residents there received a warning three hours after the Alaska quake began. Many evacuated before the tectonic wave came in, just before midnight.

Half an hour later a second wave, lower than the first, rolled into the harbor.

“People thought that was it,” said Lori Dengler, a professor of geology at Humboldt State University in Northern California. “They came back.”

At 1:20 a.m., a wave swirled into the waterfront that broke the tide gauge. The fourth wave is estimated to have reached 22 feet, Dengler said. “It was terribly timed. It came just at the top of the tide.”

More than 100 homes were destroyed. Eleven people died. Damage was estimated at $23 million.

Others died in the rising waters at Newport, Ore., and Klamath River, Calif. Damage of $600,000 was sustained by boats and harbor facilities in San Raphael, Calif.

In Hawaii, tsunamis from the Alaska earthquake cadid about $70,000 in damage. Waves in several places were as high as the one that devastated Crescent City.

But no lives were lost. When the tsunami warning sirens went off, the Hawaiians paid heed. They’d learned from another Alaska quake 18 years before.


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