Expert: Philip Stahl - 2/18/2009

Question
Hi,
I was wondering if you could please tell me if when a large meteor, such as the one that led to the dinosaur extinction, or an extinction level event, releases any radiation such as a bomb might. I know they say a strike  is equal to (X) number of nuclear bombs (or pounds of TNT) being set off thus my wondering if such an event would produce radiation and resulting effects such as an emp pulse blanking out communications and or power sources?

also if such a strike happened in an area of a fault could it lead to the disruption of the fault and a chain reaction activating connected volcanoes and faults?

Thank you
Robert

Answer
Hello,

Typically large asteroids such as the one that impacted 65 million years ago (and was possibly responsible for the dinosaurs' demise) do not directly release any radiation of the type we normally associate with human H-bomb detonations. If such radiation is released, it would be because the asteroid impacted directly on a major nuclear power plant or affected many large power plants together. (Such as exist in France, which derives 80% of its energy needs from nuclear power)

An EMP is also unlikely because it requires a high altitude detonation of a powerful bomb (e.g. H-bomb). But most asteroids will simply directly impact the Earth where they will churn up vast amounts of dust, debris and create a huge crater, or - in the case of the object that removed the dinosaurs, also create conditions similar to a "nuclear winter".

This is the aftermath situation wherein trillions of tons of dust and debris act as filters above the Earth and prevent sunlight from reaching the plants, crops below. When that occurs, as it did with the dinosaurs, their food chain collapsed. It would happen with a similar impact in our own era.

As for impacting an extensive fault area, like the San Andreas, yes, that would also trigger immense earthquakes which would probably continue indefinitely. Even the aftershocks in that case would likely be of Richter 7-8 scale or more.

Let's hope that an asteroid strike of that nature doesn't happen to us. But many space aficionados have pointed to that possibility - including of impact of a life exterminating asteroid of 10 km or more in diameter, as being one major reason for humans colonizing other planets. As Asimov once put it in a talk he gave in Barbados in February, 1975: "It is really dumb to keep all our 'eggs' in one basket."