Geography 2152F/G Lecture Notes - Lecture 5: Infrasound
27 Apr 2018
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GEOG 2152: Geography of Hazards
Video:
Chelyabinsk Meteor
1. What is infrasound? How does its analysis provide clues that a meteor may have
exploded in the atmosphere?
Explosion power was 500 kiloton, 10x more
Extremely low frequency soundwaves weren’t able to be heard by humans., however this
meteors soundwaves had infrasound waves go around the world multiple times.
2. How do small depressions form in meteors?
Small depressions formed as the object was hurtling through the atmosphere
Little vortices of air scour the rock away
3. In the laboratory, why are the scientists interested in learning about the density of the meteor?
The Chelyabinsk meteor fragments were found to be 90% rock and 10% metal. What else did
the microscope scans reveal about the meteor fragments?
Density is a factor in understanding the meteor explosions and the potential destructive
power they hold
A weak, low density asteroid will break up and explode higher up in the atmosphere, a
denser, stronger asteroid will make it deeper into the atmosphere and explode at lower
altitudes
The microscope scans reveal that the meteorite fragments have significant internal cracks,
weaknesses that would have contributed to the sudden, explosive breakup of the rock.
4. How is the angle of the meteor related to the intensity of the shockwave felt at Earth’s surface
(i.e. which types of angles would create more intense shockwaves)?
- A sharper angle would create more intense shockwaves, as it would plunge more
directly towards the ground
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