A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors

dc.contributor.author Brown, P.G.
dc.contributor.author Assink, J.D.
dc.contributor.author Astiz, L.
dc.contributor.author Blaauw, R.
dc.contributor.author Boslough, M.B.
dc.contributor.author Borovicka, J.
dc.contributor.author Brachet, N.
dc.contributor.author Brown, D.
dc.contributor.author Campbell-Brown, M.
dc.contributor.author Ceranna, L.
dc.contributor.author Cooke, W.
dc.contributor.author de Groot-Hedlin, C.
dc.contributor.author Drob, D.P.
dc.contributor.author Edwards, W.
dc.contributor.author Evers, L.G.
dc.contributor.author Garces, M.
dc.contributor.author Gill, J.
dc.contributor.author Hedlin, M.
dc.contributor.author Kingery, A.
dc.contributor.author Laske, G.
dc.contributor.author Le Pichon, A.
dc.contributor.author Mialle, P.
dc.contributor.author Moser, D.E.
dc.contributor.author Saffer, A.
dc.contributor.author Silber, E.
dc.contributor.author Smets, P.
dc.contributor.author Spalding, R.E.
dc.contributor.author Spurný, P.
dc.contributor.author Tagliaferri, E.
dc.contributor.author Uren, D.
dc.contributor.author Weryk, R.J.
dc.contributor.author Whitaker, R.
dc.contributor.author Krzeminski, Z.
dc.date.accessioned 2014-06-25T22:10:11Z
dc.date.available 2014-06-25T22:10:11Z
dc.date.issued 2013-11-14
dc.description.abstract Most large (over a kilometre in diameter) near-Earth asteroids are now known, but recognition that airbursts (or fireballs resulting from nuclear-weapon-sized detonations of meteoroids in the atmosphere) have the potential to do greater damage than previously thought has shifted an increasing portion of the residual impact risk (the risk of impact from an unknown object) to smaller objects. Above the threshold size of impactor at which the atmosphere absorbs sufficient energy to prevent a ground impact, most of the damage is thought to be caused by the airburst shock wave, but owing to lack of observations this is uncertain. Here we report an analysis of the damage from the airburst of an asteroid about 19 metres (17 to 20 metres) in diameter southeast of Chelyabinsk, Russia, on 15 February 2013, estimated to have an energy equivalent of approximately 500 (6100) kilotons of trinitrotoluene (TNT, where 1 kiloton ofTNT54.18531012 joules).Weshowthat a widely referenced technique of estimating airburst damage does not reproduce the observations, and that the mathematical relations based on the effects of nuclear weapons—almost always used with this technique—overestimate blast damage. This suggests that earlier damage estimates near the threshold impactor size are too high.Weperformed a global survey of airbursts of a kiloton ormore (including Chelyabinsk), and find that the number of impactors with diameters of tens of metres may be an order of magnitude higher than estimates based on other techniques. This suggests a non-equilibrium(if the population were in a long-term collisional steady state the size-frequency distribution would either follow a single power law or there must be a size-dependent bias in other surveys) in the near-Earth asteroid population for objects 10 to 50 metres in diameter, and shifts more of the residual impact risk to these sizes.
dc.format.extent 4 pages
dc.identifier.citation (2013) A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors. Nature, 503:238-241
dc.identifier.uri http://hdl.handle.net/10125/33201
dc.publisher Nature Publishing Group
dc.relation.uri www.nature.com/doifinder/10.1038/nature12741
dc.title A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors
dc.type Article
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