Airblast damage from small asteroids
The fragmentation of a small asteroid in the atmosphere greatly increases its cross sections from aerodynamic braking and energy dissipation. At a typical impact velocity of 22km/s, the atmosphere absorbs more than half the kinetic energy of stony meteoroids with diameters, D{sub M} < 250 meters and iron meteoroids with D{sub M} < 60 meters. Most of this energy dissipation occurs in a fraction of a scale height, which causes large meteoroids to appear to ``explode`` or ``flare`` at the end of their visible paths. The dissipation of energy in the atmosphere reduces the damage due to direct impacts (e.g., craters and tsunamis), but it produces a blast wave than can cause considerable damage to structures on the ground. The area of destruction around the impact point in which the over pressure in the blast wave exceeds 4 pounds/inch{sup 2}=2.8{times}10{sup 5}dynes/cm{sup 3}, which is enough to knock over trees and destroy buildings, increases rapidly from zero for chondritic asteroids less than 50 meters in diameter (9 megatons) to about 2000 square km for those 80 meters in diameter (40 megatons), the approximate diameter of the Tunguska impactor of 1908. The area of destruction produced by the blast wave from the impact of stony asteroids between 70 meters and 200 meters in diameter is up to twice as great as it would be without fragmentation.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10165467
- Report Number(s):
- LA-UR--92-2049; CONF-920191--2; ON: DE92017834
- Country of Publication:
- United States
- Language:
- English
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