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At about 10:38 am on February 12, 1947 the largest shower of meteorites in historical times fell on the slopes of a hill in the Sikhote-Alin mountains in the U.S.S.R. Around 8,500 pieces of an iron meteorite, weighing more than 23 tons, fell in an area of 1.6 kilometres square.
Eye Witnesses
The fall was witnessed by large numbers of people up to 180 km from the impact site. The meteorite generated a bright fireball, sonic booms and a trail of dust 33 km in length. The trail lasted for several hours before it was dispersed by the wind and the sonic booms were heard up to 400 km away.
The Meteorites
By the time the meteoroid had reached Sikhote Alin it had been slowed down by the atmosphere to around 1 km/s and had broken up into pieces. At this speed many of the meteorites penetrated the soft ground on the side of the pine-covered hill making vertical sided pits up to 12 m deep. One fragment, weighing 13.4 kg, partially split a 70 cm thick cedar tree.
The largest iron meteorite recovered from the Sikhote-Alin fall weighed 1.7 tonnes and in total around 70 tonnes of the Sikhote-Alin meteorite are thought to have fallen, including dust. All the recovered meteorites were deeply pitted by thumb-shaped depressions known as regmaglypts, formed by sculpting by the air.
It is probably only because Sikhote-Alin was an iron NEO that it survived passage through the atmosphere. A weaker stony object would have probably been completely destroyed before it hit the ground.
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