Krakatoa By Chirag Shah

What were the after effects?

Home
-- What is a Volcano?
Introduction
Where is Krakatoa?
What was the scene before 1883?
What were the events leading up to the 1883 eruption?
What happened in the major eruption of 1883?
Why did Krakatoa erupt?
Who was affected by the eruption?
What were the after effects?
Reconstruction
What is Anak Krakatoa?
Anak Krakatoa Images
Bibliography
ICT EVALUATION

Pyroclastic flows, volcanic ashes and the tsunamis generated by explosion had disastrous results. There were no survivors from 3,000 people located at island of Sebesi, about 13km from Krakatoa. Pyroclastic flows killed around 1000 people at Ketimbang, located at coast of Sumatra some 40km north from Krakatoa. Official death toll by Dutch authorities was 36,417 and many settlements destroyed, including Teluk Betung and Ketimbang in Sumatra, and Sirik and Semarang in Java. The areas of Bantam on Java and the Lampongs on Sumatra were devastated. Ships as far away as South Africa rocked as tsunamis hit them, and the bodies of victims were found floating in the ocean for weeks after the event. There are numerous documented reports of groups of human skeletons floating across the Indian Ocean on rafts of volcanic pumice and washing up on the east coast of Africa, up to a year after the eruption. Some land on Java was never repopulated; instead, it reverted to jungle and is now the Ujung Kulon National Park.

During the time period just after the Krakatoa eruption, many people, places and objects were affected by the immense burst of power from the "monster." - (The literal meaning of 'Krakatoa.') Because of this explosion, thousands of people were killed and many buildings destroyed.

 
Before we even start to talk about the effects on houses, people and other living things, we need to know about the explosion and the affect it had on the atmosphere. The third blast from the volcano, which was also the strongest, sent pressure waves into the atmosphere. These were able to be measured by barometers at weather stations all over the world. These pressure waves circled the earth for several days until they eventually lost their power and faded away.
 
For two days Krakatoa and the area around it was covered in the darkness of black clouds. These black clouds were the remains of Krakatoa. Floating around in the air along with that there was a shower of black particles from the volcano which covered many of the surrounding islands with a layer of ash. The clouds blocked out the sun for many days, and afterwards caused brilliant red sunsets, which continued for years. Also volcanic ashes were blown as far away as New York, and into the upper atmosphere changing the weather of the Earth for years to follow.
 
The most destructive effect of the eruption were the tidal waves. Tidal waves are caused by activities that move large amounts of water. Such activities are seaquakes, landslides, or volcanic eruptions. Tsunamis (better known as tidal waves) were the major cause of death from the eruption. The waves were about 100 feet high and sometimes higher. Many of the inhabitants of the Indonesian islands were washed away with waves, among the islands hit were Java and Sumatra the total death count was around 36,000 people. These waves even reached as far away as the English Channel. Along with the explosion five cubic miles of magma was pulverized and thrown out into the atmosphere. The effects of the eruption have worn out by now but what they have done will be remembered for a very long time.

 

THE ATMOSPHERE

 

  • The earth’s tropopause surface area is ~5.2x108 km2.
  • Eruption plume could have produced a cloud layer from 20 to 150 m thick over the entire globe.
  • With the plume source near the equator, both north and south hemispheres would be affected.
  • Such a large magnitude volcanic plume has never been considered for CGMs, and its only analog might be the ejecta plume of the K-T impact.
  • Application of nuclear winter models (soot) for the K-T impact indicate such a burden of particles in the stratosphere would cause collapse of the troposphere.
  • In addition the large volume of water vapor may produce huge stratospheric ice clouds, leading to destruction of the ozone.

    Atmospheric profile

    The global climate impact might involve:

    • Initial global cooling by 5 to 10 degrees C or more lasting over 10 to 20 years, caused by the increased global albedo.
    • Subsequent global warming with remaining water vapor acting as a greenhouse gas and decreased ozone.
    • FIG 4.5 below: An artistic rendition of the hypothetical cloud cover over the earth's surface within days after the eruption.

    FIG 4.5:

  • Artistic portrayal of hypothtical cloud cover

     
     
     
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