The Alaskan Earthquake Of 1964 Essay Research

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The Alaska earthquake of 1964 and following tsunami took 125 lives (tsunami 110, earthquake 15), and caused about $311 million in property loss. It is the biggest earthquake ever measured with an intensity of 9.2 on the Richter Scale. Earthquake effects were big in many towns, including Anchorage, Chitina, Glennallen, Homer, Hope, Kasilof, Kenai, Kodiak, Moose Pass, Portage, Seldovia, Seward, Sterling, Valdez, Wasilla, and Whittier. To give an overview of where all these places are in Alaska, here is a map taken from Microsoft Encarta:-

Even though the map is not very detailed, you can see which areas this great earthquake hit.

An earthquake is all to do with Plate Tectonics. As two massive plates collide against each other, pressure builds up until one plate finally gives way. At this point massive pressure is released and seismic waves travel through whatever they meet. If water is near to an earthquake a Tsunami can occur. These can be devastating. The two plates which caused the Anchorage earthquake was the Pacific Plate (Oceanic plate) and the North American Plate (Continental Plate.) These two plates have caused a subductive margin in which the thinner and denser oceanic plate dives under the thicker and less dense continental plate. Over the years pressure would have built up when the two plates got stuck moving, and when one gave way the Anchorage Earthquake began. Below is a diagram in which the oceanic plate travels underneath the continental plate, like with the North American Plate and the Pacific Plate.

Anchorage was about 120 kilometers northwest of the epicenter and suffered the most severe damage to property. About 30 blocks of houses and flats and business buildings were damaged or destroyed in the city center. The J.C. Penny Company building was damaged beyond repair and a new six-story structure collapsed, and many other multistory buildings were damaged badly. The schools in Anchorage were almost devastated. The Government Hill Grade School suffered a landslide and was almost a total loss. Anchorage High School was damaged severely. The shock lasted for an estimated 3 minutes.

Landslides in Anchorage caused a lot of damage too. Huge slides happened in the main business section. The largest and most devastating landslide occurred at a place called Turn again Heights. An area of about 130 acres was devastated by displacements that broke the ground into many blocks that were collapsed and tilted at all angles. This slide destroyed about 75 private houses. Water mains and gas, sewer, telephone, and electrical systems were damages throughout the area.

The earthquake was accompanied by vertical displacement over an area of about 520,00 square kilometers. The worst part of the displacement centered northeast from southern Kodiak Island to Price William Sound and carried on east-west. Vertical displacements ranged from about 11.5 meters to 2.3 meters. Off the southwest end of Montague Island, there was a vertical displacement of about 13 – 15 meters. Uplift also happened along the southeast coast of Kodiak Island . This zone of subsidence covered about 285,000 square kilometers, including the north and west parts of Prince William Sound and the west part of the Chugach Mountains,

This shock made a tsunami that devastated many towns along the Gulf of Alaska, and left serious damage along the West Coast of the United States (15 killed), and in Hawaii. The maximum wave height recorded was 67 meters. .

The earthquake was felt over a large area of Alaska and in parts of western Yukon Territory and British Columbia, Canada. Below is a map, which I retrieved from the United States Geological Survey Web site on the Internet. The map clearly shows where the epicenter of the earthquake was, and which areas were hit the hardest.

The Precise place, time and size for the earthquake was Prince William Sound, Alaska 1964 03 28 03:36:14 UTC (03/27), 9.2 . Long Term Effects of the earthquake were no where near as bad as the short term effects. Since the cost of the earthquake was in the order of $311 million for property loss alone and with the loss of many businesses in the area, the economy in the area suffered. People in the area also became homeless and many people lost friends and family due to the earthquake or following events. This put people off moving to Alaska and also caused many people to move away from the area.

Constant tremors are common in the area, such as this account from Deputy State Seismologist Charlotte Rowe, at the Alaska Earthquake Information Center, Geophysical Institute, University of Alaska Fairbanks.

“During July 1996, the Alaska Earthquake Information Center located 410 earthquakes in or near Alaska. The largest earthquake during the month, having a magnitude of 5.6, occurred on July 4 at 3:39 a.m. This earthquake was located in Cook Inlet, about 13 miles east-southeast of Skwentna, and 54 miles northwest of Anchorage. This quake was felt in Anchorage, Palmer, Wasilla and Willow.

Thirty-eight earthquakes of magnitude 4.0 and larger occurred during the month; these are labeled on the accompanying map. Sixteen of these are aftershocks of the June 9, magnitude 7.9 earthquake in the Andreanof Islands (near Adak).

Other earthquakes of interest during July include:

July 23 at 7:59p.m. ADT, a minor earthquake of magnitude 3.7 occurred six miles east-southeast of Eielson Air Force Base and 11 miles north of Salcha. This earthquake was felt at Eielson, along Badger Road and in Salcha.

July 27 at 3:17 a.m. ADT, a light earthquake of magnitude 3.6 occurred 17 miles north-northwest of Anchorage. This earthquake was felt in Anchorage and Eagle River.”

Stories like this make you wonder why people live in earthquake prone areas. Perhaps it is because of the cheap land, good fertile soil or just the adventure of living on the edge.

9.2 on the Richter scale is an absolute massive earthquake, in fact the largest ever recorded. Just to show how large and intense the earthquake was I have drawn out a table showing just how big it is compared to other earthquakes.