Chile earthquake, 1960

Prepared by:- Raval Chaitanya V. (12012071109)

Introduction

In the list of the greatest earthquakes in the world, Chile earthquake is remarked in top having the magnitude of ‘9.5’.

It is the largest earthquake recorded in the century.

The rupture zone was estimated around 1000 km from Lebu to ‘Puerto Aisen’.

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Chile earthquake was originated off the coast of southern Chile on May 22, 1960 which caused substantial damages and loss of life both in that country.

Earthquake hit at 19:11:14 UTC approximately at 100miles (160 km) off the coast parallel to the city of ‘Valdivia’ at a depth of 33km.

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The magnitude was noted 9.5 yet according to different research papers the value lies in between 9.4 to 9.6 .

There were 4 foreshocks having the magnitude over 7 were noted down.

One of them was 7.9 which caused a great damage in the Concepcion area.

Many aftershocks of 5, 7 or greater than it through Nov 1.

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Many Chilean cities including Puerto Montt where noticeable subsidence occurred and Valdivia where nearly half of the buildings were rendered uninhabitable.

In 1960’s, there was not a digital seismography available for the instant analysis for the earthquakes as the results are carried out based on ‘post hoc analysis’.

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Reason

The reason why the earthquake occurred is that that the subduction of Nazca plate under the South America plate on which the Chile is rested.

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The locking and rupture of plates

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Fig. shows the subduction of Nazca plate under the South American plate.

The position of plates

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Causes

After 15 min of the earthquake, due to shifting of the South American plate, tsunami generated having a wave height of 80 feet (25 m).

The water rushed into the coastline of Chilean which is bounded by cities Lebu-Puerto Aisen.

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The epicenter of chile earthquake

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The combined effects of disaster led two million people homeless and estimation of total loss of $300 million.

After that the cost reached to $550 million.

At first there were 1600 people dead and 3000 were injured but after the analysis 6000-10000 people were missing or dead.

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The tsunami arrived at Hawaiian Island after nearly 15 hours later which is almost 10000km away from the Chile.

The waves still crested 35 feet at landfall in some places of Hawaiian.

Caused $75 million of damage at ‘Hilo Bay’ which is the main island of Hawaiian, got 61 people killed.

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The image of valvidia

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The images of valvidia

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Tsunami reached at Japanese island of Honshu 22 hours of generation.

The waves had subsided 18 feet.

Caused 1600 homes demolished and 138 people killed as there be many lower laying areas in that island, overall damage was $50 million.

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Waves reached at Phillippines having crest of 5.5 feet.

32 people were killed in Phillippines due to the tsunami.

Caused $0.5 million damages in the West coast of U.S.

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Many landslides occurred in the Chilean lake district from ‘Lago Villarica’ to ‘Lago Todos los Santos’.

As Chilean lake district has two complex volcanos named Puyehue and ‘Cordon Caulle’.

Both the volcanos are neighboring, lie on same transverse fault and has been noted that they tend at same time or nearby.

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Puyehue volcano has a 2.4 km wide summit caldera yet the historical eruptions occurred at the Cordon Caulle rift zone.

Cordon Caulle geothermal area occupies (6 × 13) km wide depression and is the largest active geothermal area in Southern Andes.

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Puyehue-cordon caulle volcano

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The Puyehue-Cordon Caulle volcanos started erupting on May 22, 1960.

So it may be possible that the great earthquake made the eruption started, cause they are just 200 km away from epicenter.

As the result of that the 51 years of inactivation the great volcano came in action. The ashes of the volcano went 8 km heigh in the sky.

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The earthquake could have made more damage but it occurred at afternoon, many of the structures had been built earthquake-resistant and the series of foreshocks made population wary.

According to different research papers, total people got killed were 3000, 5600 respectively and the damage caused was $417, $675, $800 millions respectively.

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References

USGS Britannia.com VOLCANO DISCOVERY

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