Asteroids: how many deaths in case of impact?

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DEEP IMPACT. 8.8 million dead … Such would be the appalling record if an asteroid 200 meters in diameter crashed in the heart of London , according to a study carried out by engineers, physicists and geographers of the University of Southampton, In the south of England. 

Using a computer program called „Armor“ (Asteroid Risk Mitigation Optimization and Research), they assessed the mortality rates associated with three scenarios: an explosion in the atmosphere, a collision on land and in the ocean.Their model integrates many parameters such as the size, the composition and the speed of the asteroid, as well as the population densities, Habitats in different regions of the world. Losses in human life were also estimated based on the seven main phenomena resulting from the fall of an asteroid:

  • extremely violent winds,
  • shock waves,
  • thermal radiation,
  • earthquakes,
  • rock projections,
  • crater
  • tsunamis.


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Meteorological phenomena would be the most devastating 

Surprisingly, it is the meteorological phenomena that would be the most devastating … whatever the scenario envisaged! The overpressures, tornadoes and gusts of wind caused by the explosion of an asteroid 50 meters in diameter over London would indeed be responsible for 85% of the victims (for a total of 2.8 million deaths), Others succumbing to intense heat. 

And if a 200-meter diameter meteorite crashes into the heart of the British megalopolis, these winds would cause 49% of the deaths (8.8 million), the other deadliest causes being Thermal radiation (24%) and shock waves (23%) that destroy internal organs. The projections and the crater itself would thus cause „only“ 3% of deaths.

The same can be said for a fall in the ocean: an asteroid of 200 meters in diameter, for example, 100 kilometers from the coast of Rio de Janeiro in Brazil, would make 30,000 victims – 92 per cent because of strong winds, and 8% only by the resulting tsunami.

Fortunately, asteroids of this size do not impact the Earth, on average, only once every 40,000 years! There is only a 0.01% likelihood that such a catastrophe will occur in the 21 st century … And this probability concerns the whole of the earth’s surface, which on the whole (oceans, mountains, desert zones, tundra, Etc.) is not inhabited.