1964 Anchorage, Alaska, earthquake and tsunami, arrested without warning on Good Friday, March 27.
It was a quiet spring day in Anchorage, a holiday. Temperatures were seasonally mild with moderate amounts of snow on the ground. The children had a day off from school, and the movement of customers in the city center was easy. Many residents cooked or enjoyed dinner at home. At 5:36 pm, a major earthquake began to shake the earth, and the earth failed in south-central Alaska moving in waves for the next four long minutes.
Parents and children slipped, stumbled and fell on shifting floors in a panic, trying to go outside to avoid breaking windows. In many places, two inches wide cracks appeared on the ground. Roads wrinkled and split, and Fourth Avenue in the center of Anchorage collapsed and collapsed 10 feet or more. Hill’s Elementary School spun, faded into the background and became unusable. The outer wall of the JC Penney building crashed into the street. In the residential area of Ternagain, the land sank like quicksand, slipped and swallowed 75 or more houses.
The four-minute earthquake released energy approximately equivalent to the energy of an atomic bomb 10 million times. The mass of land and ocean absorbed most of the force, but the man-made structures in the area could not absorb the rest of the force without causing enormous damage. The total damage to property is estimated at 500 million dollars.
Anchorage was damaged, as gas and water lines were sharply destroyed. Residents resorted to melting snow for water, waiting for repairs. Four days later, students returned to available schools, as life in Anchorage began to recover.
Earthquake
The center of the Alaska earthquake was located about 75 miles east of Anchorage and about 55 miles west of Valdez. It began at a depth of 14-16 miles in the earth's crust, a relatively shallow depth, where diving on the Pacific plate benefits the North American plate. A huge subduction zone is located at the northern end of the Ring of Fire, a volcanic semicircle and earthquake that defines the rim of the Pacific Ocean.
Damage to the earthquake, more precisely the destruction of the thrust that caused the earthquake on Good Friday, stretched 750 miles from the Aleutian Islands of Alaska to Valdez. The Pacific Plate on this day moved about 25–30 feet to the north, plunging under the North American plate. The grinding of two massive tectonic plates caused an earthquake in Alaska and measured 8.4 on the Richter scale. In subsequent years, the measurement of Alaska earthquakes was upgraded to 9.2 on the Mw scale or moment scale, since it was determined that the Richter scale is inaccurate when measuring very large earthquakes above 8.0. During the day of the initial major earthquake 11, more tremors 6.0 or more shake up the already nervous population. In fact, the aftershocks continued for almost a year.
The earthquake caused the earth to shift by as much as 25 feet in several Alaskan islands and nearly 3 feet up in the city of Valdez. In other areas, the earth moved down 9 feet, for example, in the city of Portage.
The Good Friday earthquake in Alaska was the strongest earthquake ever recorded in North America. It was the second largest record recorded worldwide, surpassed by a 9.5 MW earthquake in Chile on May 22, 1960. The recent earthquake off the coast of the Indonesian island of Sumatra on December 26, 2004 was 9.0 MW. The deadliest earthquake occurred in the province of Shaanxi, China, in 1556, where more than 830,000 people died.
Tsunami
Tsunami is an adapted Japanese word meaning “port wave”, referring to the fact that the danger and destructive force of the wave became apparent only when approaching the coast.
During an earthquake in Alaska in 1964, the North American plate went up, displacing a huge amount of ocean water and causing a tsunami surge in the form of a seismic wave. The wave passed at a speed of 450 miles per hour in a deeper ocean in a long wave of almost imperceptible height.
As the tsunami wave passed over the continental shelf and approached the coast, its length decreased, its speed decreased, and its height increased as the massive volume and weight of the water were ready to release their incredible energy to anything of the way.
At the shallow entrance of Valdez, the wave reached a maximum height of almost 200 feet. Further, in the old town of Valdez, a 30-foot wall of water stuck and destroyed all the buildings. Twenty-eight residents of Valdez were killed when the tsunami crashed ashore. Valdez was later rebuilt at a higher level and farther from the embankment.
In Seward, Alaska, an earthquake caused part of the bay to slide. The slide caused a local tsunami that devastated the port of Seward and the city center, both of which were eventually restored. Twelve inhabitants died in Seward.
The small town of Portage owed its local tsunami and never moved or rebuilt. Another local tsunami hit the small port of Whittier, killing 12 people.
Destruction
The initial tsunami passed about 8400 miles. It caused damage to the Hawaiian islands and along the Oregon coast and California. The 20-foot wave cut Crescent City, California, and killed 10 residents. Tsunami is responsible for the deaths of 16 people in Oregon and California.
The tsunami killed a total of 122 people in three states. For comparison, an earthquake caused 9 deaths.
It has been more than 40 years since the earthquake and tsunami in Alaska. At the same time, building materials and construction methods were put in place to produce structures that are more able to survive by strong earthquakes. At the same time, the population in vulnerable areas of Alaska has increased significantly.
Smaller earthquakes along the subduction zone of Alaska and other fault zones occur daily, which apparently reduces internal pressures that would otherwise lead to another massive earthquake.
However, no one knows with certainty when, where, or another gigantic and destructive land will strike in Alaska.
