Download E Earthquakes Seismology and Society Student E Due 10/9/14 1964

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Earthquakes Seismology and Society
Student E
Due 10/9/14
1964 Great Alaska Earthquake
There are several earthquakes that have impacted Alaska in a big way throughout history.
One earthquake that affected Alaska was the 1964 Great Alaskan Earthquake. This earthquake
had the highest magnitude ever recorded at 9.2, in the United States and North America. It was
the second strongest earthquake ever recorded. The 1964 Great Alaska had a great impact on
Alaska in many different ways. This earthquake caused damage throughout the city of
Anchorage that hurt them in different ways. The people and city of Alaska were impacted from
the destruction of the earthquake. This event helped confirm the theory of plate tectonics and
provided insight on earthquake processes, tsunami generation, and the impacts of these
phenomena on communities, both locally and across the Pacific (Bolt, 16). The 1964 Great
Alaska earthquake had a great historical impact on its people, severe economic damage on the
cities of Anchorage, Kodiak, Valdez, and Seward, left the greatest area of vertical displacement
ever recorded in earthquake history and provided a theory of plate tectonics.
The people of Alaska suffered in a variety of ways. There were 135 people that died,
only 9 from the actual ground shaking. The other 126 people suffered the effects of the tsunami
that occurred along the coast. The 1964 Alaska tsunami was the second largest ever recorded,
following only the one caused by the 1960 Chile earthquake. Two types of tsunami were
produced by this earthquake. There was a tectonic tsunami produced in addition to about 20
smaller and local tsunami. The smaller tsunami’s were produced by submarine and sub aerial
landslides and were responsible for most of the tsunami damage. As they surged onshore, it
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devastated waterfronts along the Alaskan coast, particularly at Valdez and Seward (Brumbaugh,
158).
The shaking caused some people to record their thoughts as the earthquake was
happening. One person that recorded his thoughts was R. Pate, the announcer at a local radio
station.
He said “I have never lived through anything like this in my life. That’s the worst
thing I have ever lived through in my life” (Bolt 16). This statement shows that people were
terrified of what was going on. The magnitude was so great that no one ever experienced
anything like it before. Many people feared for losing their houses or their lives (Bolt 16).
Another person that witnessed the effects of the earthquake was Rocky Plotnick. Rocky
was in the airport when the earthquake occurred. He couldn’t believe how bad it was. He
explained that the “noise was horrific. It was a bit like being on a boat in a confused and stormy
seas” (“The 1964 Great Alaska Earthquake & Tsunami”). When he arrived home after the
earthquake, his dad’s shop and inventory were destroyed. His dad’s store was on a block that
sunk two stories.
William Ziesemer, a policeman was also effected by the earthquake. William was on
duty while the earthquake occurred. He was with a few of his other co-workers when it
happened. A couple of them started screaming bomb and a couple started screaming earthquake.
They quickly rushed outside and their Sargent told them to search the area for any injured.
Luckily no one was injured too badly and everyone made it out of their houses.
Edward Jackson lived right next to a military base. The shaking started when he was
outside reading a newspaper. He quickly ran inside and a huge refrigerator toppled over nearly
missing him. One fighter plane that had come in that day, and was new, was nose into the
ground. The shaking snapped the nose landing gear off. The house was destroyed and luckily for
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him the neighbors took him in until he was able to find somewhere else to go. (“The 1964 Great
Alaska Earthquake & Tsunami”).
The schools of Anchorage were impacted in a big way. The landslide caused many
schools to be on different levels of the ground. The Government Hill Grade School, sitting
astride a huge landslide, was almost a total loss. Rock Avalanches are among the most
dangerous landslides to occur during the effects of an earthquake. With the exception of
unconsolidated soils, rock avalanches have killed more people than any other type of landslide.
The Rock Avalanches that occurred in the 1964 Great Alaska earthquake did severe damage that
affected a large area of alpine terrain (Keefer 1288).
Anchorage High School and Denali Grade School were damaged severely. Due to the
vertical displacement of the ground, the schools were uneven in many different spots. This result
made it almost impossible to reopen the schools. Also fires broke out that destroyed files and
supplies that the school needs. Schools do not have the money to fix that type of damage. The
students and teachers suffer tremendously because they are forced to move to a different school.
It is not just the schools that are effected from the damage. The destruction of people’s
homes cause many families to lose their houses and have nowhere to go. An area of about 130
acres in Turnagain Heights was devastated by displacements that broke the ground into many
deranged blocks that were collapsed and tilted at all angles. This slide destroyed about 75 private
houses (USGS.gov). This shows that where you build houses does matter. Much of the damage
and the loss of life in the earthquake was the direct result of building on poor foundation
materials. The underwater landslide that took the waterfront and pier at Valdez is one example.
Another example was the Turnagain Heights landslide. The best prevention of damage is to be
careful where you build. The death toll was extremely small for an earthquake of this magnitude
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because the population density was low, the time of day and that it was a Good Friday, and the
type of material used to construct many buildings was wood. But it wasn’t just the people living
in the cities near the earthquake that were deeply affected by the earthquake. This great
earthquake was felt over a large area of Alaska and in parts of western Yukon Territory and
British Columbia, Canada. (Brumbaugh 158).
There was severe economic damage that hurt the areas of Valdez, Seward, Kodiak, and
Anchorage tremendously. The Building damage in Southern Alaska varied considerably. The
Port of Valdez was almost all destroyed. As shaking began, the waterfront slid into the bay,
carrying the pier with it and creating a giant wave. Valdez was pummeled by the waves and half
the buildings in Valdez were unusable or completely destroyed. In Seward there is a major oil
terminal and freight yard for the Alaska railroad. The terminal was devastated by ground
shaking and tsunamis. Due to large oil tanks, there were large fires that broke out as well. When
the waterfront slid into the bay, oil pipelines ruptured and the contents ignited causing oil tanks
to explode. The combination of fire, ground shaking, land sliding of the waterfront into the bay,
and tsunamis totally destroyed the Alaska railroad yards, also flipping 125-ton locomotives in the
process.
Also a shock generated a tsunami that devastated many towns along the Gulf of Alaska,
and left serious damage along the West Coast of the United States and in Hawaii. Anchorage
suffered severe ground shaking, lasting about 30 to 60 seconds. Small houses survived the
shaking well but large buildings were destroyed. Because of the distance from the rupturing
fault, ground shaking consisted mainly of the long waves that do not affect small buildings. The
building's vibrations tend to center around one particular frequency that is known as its natural
frequency. Usually, the shorter a building is the higher its natural frequency, and the taller the
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building is, the lower its natural frequency (mceer.buffalo.edu). The concrete control tower at
Anchorage airport and a brand new six story apartment house collapsed. Wood frame homes
were reasonably unaffected, although their occupants were disturbed and furniture was knocked
over. Downtown Anchorage also suffered devastation. The brand new J.C. Penney department
lost its facade. The facade consisted of large suspended concrete slabs. The slabs came
tumbling down into the street crushing cars and people. The rest of the business district avoided
total destruction, but a quarter mile section of Fourth Avenue sank more than 10 feet. Shops and
cars were being whipped and carried around. Due to the damage in the cities, there was
significant property damage suffered in Alaska. The property damage caused about $2.3 billion
in property loss (in 2013 dollars; equivalent to $311 million in 1964) (mceer.buffalo.edu).
The magnitude of the earthquake was so great that it was the greatest area of vertical
displacement ever recorded in earthquake history. The vertical displacement was over an area of
about 520,000 square kilometers. There were many areas that were uplifted by this displacement
but the main area that was uplifted went northeast from southern Kodiak Island to Prince
William Sound. Vertical displacements ranged from about 11.5 meters of uplift to 2.3 meters of
subsidence relative to sea level (Bolt 15). The vertical tectonic movements in coastal areas were
measured by making more than 800 measurements of displacement of intertidal marine
organisms along the long coast. These measurements were placed at 16 tidal bench marks by pre
and post-earthquake tide- gauge readings made by the U.S. Coast and Geodetic Survey. They
were also measured by many estimates of relative changes in tide levels by local residents. The
amount of movement of the vertical tectonic movements inland from the coast showed along the
highways connecting the cities of Seward, Anchorage, Valdez, and Fairbanks. The U.S. Coast
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and Geodetic Surveys revealed previously surveyed first-order level lines tied to bench marks at
Seward, Anchorage, and Valdez (Plafker 1675).
The Geological Survey found out that an Alaskan Island rose about 30 feet by the
earthquake. The agency discovered that it was Montague Island in Prince William Sound, which
was about 100 miles south of the epicenter location. Geologists said that the Island shot up to
expose a strip of sea floor about 1350 feet in width ("An Alaskan Island was Lifted 33 Feet by
Quake's Force."). As a result of the extreme vertical displacement during the earthquake, the
area near the Latouche Island moved about 18 meters to the southeast. The patterns of uplift and
subsidence were reversed, which had been developing prior to the earthquake. There were areas
around Montague Island being uplifted 4-9 meters and areas around Portage down-dropped as
much as 3 meters.
One of Alaska’s biggest rivers and lakes went dry. There was reports that the Copper
River stopped flowing into the sea. These reports were confirmed by an Air Force Pilot, Jack
Wilson flying about 100 miles inland from the point where the Copper River flows into the ports
of Alaska. Mr. Wilson said the Copper River was dry and so was Lake Tazlina. Mr. Wilson said
“There is ice on the surface of the lake but no water underneath” ("Alaskan River and Lake Go
Dry."). This area was 50 miles from the epicenter of the earthquake. Mr. Wilson discovered that
the water might have broken into giant fractures or that earth slides or crumbling glaciers in areas
he had not seen could have been the cause. This is just one article reported about the effects of
the Alaskan Earthquake ("Alaskan River and Lake Go Dry.").
The structure of earth’s rocks between Alaska and the Southern States may have
channeled and focused Earthquake waves. They then acted on very deep sediments laid down in
the south by millions of years of North American erosion. These sediments act like a bowl of
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jelly, which amplifies the motion. A sieche then occurred in the Kenai Lake, in Alaska. Bark on
the trees on the shore was peeled off 20 feet above the ground as water and ice in the Lake
moved back and forth. The seiche drove water up through fishing holes ("Science”).
Scientists could not figure out what caused this earthquake. There were no obvious faults
at the surface to explain the earthquake. Even with months of observation and field work, the
cause of the earthquake remained a mystery until scientist George Plafker began to study it.
George Plafker had a whole new insight on the earthquake. His new insight helped confirm the
concept of plate tectonics and changed earthquake science forever. At the time, the plate
tectonic theory was just being developed. No unifying theory existed on what caused these types
of great earthquakes. After detailed work investigating the 1964 earthquake, Plafker concluded
that this event was a “megathrust” earthquake, occurring where an oceanic plate descends
underneath a continental plate in southern Alaska. Slip between the two tectonic plates along this
kind of plate boundary, called a subduction zone, is the cause of the world’s largest earthquakes
(USGS.gov).
The Great Alaskan Earthquake caused damage in many ways resulting in devastation
throughout Anchorage, Valdez, Seward, and Kodiak. The 1964 Great Alaska earthquake had a
great historical impact on its people, severe economic damage on the city of Anchorage, Valdez,
Seward, and Kodiak, left the greatest area of vertical displacement ever recorded in earthquake
history, and provided a theory of plate tectonics. Luckily, since it was in a low populated area
and happened on a holiday the casualties were not terrible. The casualties could have been
tremendously worse if the earthquake happened on a day everyone was at work or school. God
must have been watching over us on Good Friday. This earthquake impacted the world and will
always be remembered historically.
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Works Cited
"Alaskan River and Lake Go Dry." New York Times (1923-Current file) Apr 01 1964: 24.
ProQuest. 8 Oct. 2014 FAIRBANKS, Alaska, March 31 (AP)
"An Alaskan Island was Lifted 33 Feet by Quake's Force." New York Times (1923-Current file)
Jul 23 1964: 29. ProQuest. 8 Oct. 2014 WASHINGTON, July 22 (UPI)
Bolt, Bruce A. Earthquakes. New York: W.H. Freeman, 1993. Print.
Brumbaugh, David S. Earthquakes: Science and Society. Upper Saddle River, NJ: Prentice Hall,
1999. Print.
Jones, Barclay. Mceer.buffalo.edu. Web. 23 Nov. 2014
Keefer, David. "Rock Avalanches Caused by Earthquakes: Source Characteristics." Science New
Series, Vol. 223, No. 4642 (Mar. 23, 1984), pp. 1288-129
Plafker, George. “Tectonic Deformation Associated with the 1964 Alaska Earthquake” Science
New Series, Vol. 148, No. 3678 (Jun. 25, 1965), pp. 1675-1687
"Related:" The 1964 Great Alaska Earthquake & Tsunami N.p., n.d. Web. 08 Oct. 2014.
Stover, Carl W., Coffman, Jerry L. USGS.gov. Web. 23 Nov. 2014.
SULLIVAN, -- W. "Science." New York Times (1923-Current file) Feb 16 1969: 1. ProQuest.
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