Planetary Science

Blowing a Hole in the Ocean

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Science  20 Jun 2003:
Vol. 300, Issue 5627, pp. 1851
DOI: 10.1126/science.300.5627.1851a

Dedicated searches are locating and tracking all kilometer-sized asteroids in near-Earth orbit in order to assess and anticipate potential impact hazards. To date, only asteroid 1950 DA (1.1 km diameter) has been accorded any chance of hitting Earth with up to a 0.3% probability of colliding on 16 March 2880 (see Reports, 5 April 2002, p. 132).

Ward and Asphaug modeled the impact cavity and tsunami that would be created by 1950 DA traveling at 17 km/s into the Atlantic Ocean at 35°N and 70° W. The asteroid would blow a hole through the entire ocean to a depth of ∼5 km and excavate the seafloor. Waves would propagate in a circular pattern; about an hour after impact, observers on the eastern shore of the United States would start to see small waves, which would increase in height to a maximum of about 100 m in another hour. Successive tsunamis would cause scouring of ocean sediments and submarine landslides, and possibly gas hydrate decompression. On the bright side, tsunami run-up on land would be limited to 4 km because the waves have short periods. Still, not be a good day to be at the beach.—LR

Geophys. J. Int. 153, F6 (2003).

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