The epicenter was close to the coast in Prince William Sound, halfway between Portage and Valdez. Destruction was widespread and massive.
Late afternoon on March 27, 1964, it struck, the Good Friday earthquake of magnitude 9.2, ironically so named because it happened close to Easter. It was a subduction earthquake like all the others that have so often shaken Alaska’s Peninsula and the Aleutian chain of islands over the past century. This one, however, was exceptional, the biggest in living memory. The epicenter was close to the coast in Prince William Sound, about halfway between Portage and Valdez, and from the fishing port of Cordova all the way to the Island of Kodiak there was one swath of destruction. The death toll from the earthquake and the ensuing tsunami was 125, almost all of the deaths being due to the tsunami.
In the course of the three-minute quake, numerous landslides occurred, huge rocks crashed down the mountainsides, high-rise buildings and bridges collapsed, and tidal waves as high as 150 feet swept over coastal communities, carrying away everything in their paths. One small island, Middleton, was uplifted fifteen feet. An old ship that had been sunk nearby many years earlier and was normally out of sight when the sea level was at its lowest suddenly was pushed upward and left high and dry above sea level. Fortunately, population density here is low so the death toll was light. It would be a very different story if the quake had happened in San Francisco or Los Angeles.
One landslide overwhelmed Turnagain Heights, a subdivision of seventy- five homes, many perched on a bluff with an excellent view of the ocean. The bluff disintegrated and tumbled down the slopes into Knit Arm, taking the seventy-five homes down as it went. All roads and utility lines were rendered unusable. Strange as it may seem, after the earthquake private developers were allowed to rebuild on the slide mass provided they assumed full responsibility, including liability in case of accidents, for constructing and maintaining new roads and utilities.
Anchorage was hit harder than any other city. People still remember the way the shocks persisted, each minute feeling like an hour and the dislocation of everything worsening by the seconds. Underneath each building and everywhere around on the outside the ground rose and fell like the waves of the sea. Blocks of houses slid about, pavements burst open, and huge fissures opened up in the ground. People clung to lampposts and anything else that had any degree of stability. Broken glass covered the ground. Concrete slabs breaking off buildings killed some who were walking below. Others were killed in their cars as they drove past disintegrating buildings.
At Valdez where a ship was unloading the dock where it was berthed suddenly collapsed as the whole structure was sucked under taking twenty-four people with it. None of them survived. The shoreline all along the waterfront had also collapsed and water surged violently backwards and forwards within the harbor, crushing whatever was left of shore installations. The first crest of the tsunami had arrived about thirty minutes after the earthquake, but few noticed it because it was low tide and the water reached only as far as the high water mark.
Then, about four hours later, wave after wave poured in, at intervals of thirty minutes each, flooding the town of Valdez and wrecking all of its commercial buildings and half of its homes. Fortunately, almost everyone had fled into the surrounding high ground by this time. They stayed there all night in temperatures that dropped below zero, returning to town in the morning to search for lost relatives.
West of the epicenter, at the town of Seward, a similar story to the one at Valdez unfolded with devastation from both earthquake and tsunami. Seward is an oil port and rail terminus. Again the waterfront structure disappeared beneath the water taking the installations on the dock down with it. Farther back diesel locomotives weighing more than one hundred tons were thrown on their sides. To make matters worse, there were storage tanks of gasoline at the dock that caught fire and added to the confusion. Most of Seward’s residential and commercial buildings and all of its industrial areas were obliterated.
Liquefaction had caused widespread damage to railroad tracks and bridges to a degree that geologists had never before observed. There were landslides, ground cracks, and warping of the surface almost everywhere but the geologists were surprised by the degree of twisting in different directions along railroad tracks and the contortions in bridges. Under pressure from ground failure on both sides of streams, as liquefaction allowed these pressures to build up, bridges buckled in their centers. Perhaps liquefaction played a part in the failure of Turnagain Heights.
In summary, the amount of Alaska and its neighboring coastal waters deformed by the quake was more than 100,000 square miles. Some of it had been pushed upward while other locations were dropped down. In places extending as far as one hundred miles inland the land had dropped by six feet while toward the sea land was raised six feet and in some places thirty feet. Along the subduction line a wide stretch of sea floor was heaved up forty-five feet and it was this sudden displacement of water that created the huge tsunami. Furthermore, there were lateral movements of land toward the sea from the west and north, 30,000 square miles in all.
The main tsunami generated by the earthquake moved out across the Pacific. Once the wave reached deep water its speed accelerated to more than four hundred mph. Within six hours it was in Hawaii and after a few more hours in Japan. The range of the earthquake’s influence was evident in other ways. Buildings swayed in Seattle, some ground movement was observed in Texas and similar though weaker movements were felt in Florida. In Alaska, because of the enormous power of the event, hundreds of aftershocks occurred within a few days.
The low-lying area in the town of Port Alberni on Vancouver Island’s west coast was one of the first places to be flooded. A whole subdivision of homes was destroyed there. Port Alberni is forty miles from the ocean at the head of a sea inlet and the narrowing of the inlet as it reached Port Alberni gave added impetus to the incoming wave. One local resident at the subdivision, standing in her home in a foot of water watched a neighbor’s home being picked up and sailing away in the inlet before it disintegrated into floating debris.
South of Port Alberni, a tsunami wave swept up the Fraser River for thirty miles to the Pitt Meadows area, a rich low-lying agricultural region that floods easily in times of heavy rain. Water from the tsunami was equivalent to several inches of rainfall and the farms were flooded for some time. Damage to the west coast of Vancouver Island was greater than anywhere else in Canada. One thirty-eight-foot boat that had been carried out to sea with the retreat of one wave was deposited by a second one in a different inlet. A whole Indian village of twenty homes was washed away and carried out to sea. Only two damaged buildings remained. Seiches in lakes, sometimes causing chunks of ice to be thrown up on to the surface, were commonplace all across southern British Columbia. As the tsunami continued to the south, Washington state suffered very much the same as British Columbia. Again it was the west coast that experienced the greatest damage. Six-foot-high waves shot up over the sand dunes, picking up logs and throwing them around like matchsticks. All along the coasts of British Columbia, Washington, and Oregon, forestry is a major industry and destruction of processed logs a major economic loss.
At Beverly State Park, Newport, Oregon, a family was camping. The tsunami caught them asleep on the shore in their sleeping bags. Four children were washed out to sea and drowned. The worst effects of the tsunami on America’s west coast came in California. There, failure of authorities in Sacramento to pass on the warning to coastal areas, especially to Crescent City, a location particularly sensitive to tsunamis, was disastrous. Crescent City, because of offshore underwater seamounts, has always been hit with higher waves than anywhere in coastal California whenever it experiences a tsunami from the north. This time no one there knew of the tsunami until near midnight when the first wave, a fourteen foot one, struck.
One hour later, a common time delay when the tsunami is exceptionally powerful, a sixteen-foot wave arrived and it was followed by a very big withdrawal. That should have warned local people that even bigger waves were yet to come, but it was already nighttime and little information about destruction had reached them. At 1:40 A.M. another wave arrived, twenty-one feet high, and destruction of boats and buildings followed. Several people in different locations lost their lives.
In Hawaii, due to the orientation of the generating fault, the wave heights were smaller than previous tsunamis and caused little damage. Maximum wave heights reached 12.5 feet at Hilo, eleven feet at Kuhului, and only one foot a Kanai. It was a similar story in Japan where the maximum wave height was ten inches. However, while the explanation for Hawaii and Japan seems clear, the question has to be asked, why did a place like Kitimat on Canada’s west coast and so close to Alaska not suffer damage?
An answer to this question was provided by an expert at Canada’s earthquake hazard center. He pointed out that fjords and other inlets along the west coast of North America are able to amplify or dissipate a tsunami by what is called the “natural oscillation frequency” of the fjord or inlet. This natural oscillation factor is the frequency of the natural flow of water in and out of the fjord or inlet and it can either amplify or dissipate the incoming wave. In the case of Port Alberni it amplified the incoming wave.