The morning of February 12, 1947, dawned cold but bright and sunny in
the wide Ussuri valley of Eastern Siberia. During the early morning
hours the people in the villages went about their everyday chores as
usual. Farmers fed and watered their livestock, while housewives tidied
rooms and fired up stoves for heating and baking. Miners went to work
deep underground. An artist seated himself outdoors near his home to
make exercise sketches. In a densely wooded area on the slopes of a
nearby mountain range, a logging crew began a day’s timber-cutting.
Suddenly, at 10:35 a.m., an extraordinarily large and brilliant fireball
flashed above the central part of the mountain range. It streaked across
the sky in less than 5 seconds and disappeared beyond the western
foothills of the range. Then the inhabitants of a wide area heard what
seemed to them a mighty thunderclap followed by a powerful roar like an
artillery cannonade. Many people felt a strong airwave. (Field parties
later found that those who noticed this effect were quite close to the
place where the meteorite fell.)
For several hours afterward, a large black column of smoke tinged with a
reddish-rose color stood above the place of fall. Gradually, this cloud
spread outward, became curved and then zigzag in form, and finally
vanished toward the end of the day.
The flash of the fireball and the loud noises that followed it caused
panic among the farm animals. Cows lowed mournfully and herds of goats
scattered in every direction, chickens and other fowl squawked in alarm,
and dogs ran whining for shelter or crouched against the legs of their
masters.
In the villages, the airwave blew snow off the roofs of houses and other
buildings, while the strong earth-shocks opened windows and made doors
swing ajar. Housewives were dismayed to see glass windowpanes shattered
in their frames and burning coals and firebrands jolted out of the
wood-burning stoves.
Even deep in the mineshaft, the vibrations in the air were strong enough
to snuff out the miners’ lamps, leaving the men in darkness.
On seeing the huge fireball streak across the sky, the artist put aside
his practice sketch and began a picture of the display before his
impressions of it could fade. His painting of this natural event is now
famous. Not only is it on display in scientific museums all around the
world, but a color reproduction of it has been issued in Russia as a
postage stamp.
The forester supervising the logging crew reported that his attention
was first attracted to the sky when he noticed a strange “second” shadow
rotating rapidly about the tree that cast it. On looking up, he saw a
blindingly bright fireball, twice as large as the sun, a fiery globe
that threw off multicolored sparks as it passed. Not long after the
fireball disappeared behind the trees, the forester heard a loud noise
like nearby cannonading and saw a large dark-colored cloud—later tinged
with red—billow up over the impact point. (The members of the logging
crew were among the very few persons actually abroad near the place of
fall. It turned out that they were only about 9 miles from it.)
As soon as the many eyewitnesses of the fireball had recovered from
their fright, the questions almost everyone asked were “What could it
have been?” and “Where did it come down?” To answer the first question
was not as difficult as to answer the second. Local scientists in
Vladivostok and Khabarovsk, the nearest cities of some size, suspected
from the first that a very large meteorite fall had occurred. But
exactly where? All they could be certain of was that the impact point
lay in the Ussuri taiga, a formidable wilderness.
The Sikhote-Alin mountains lie along the Siberian coast between the Sea
of Japan and the Tatar Strait. The Ussuri taiga is a vast, low-lying,
marshy, densely forested region fronting the western flanks of these
mountains. Ordinary cedars, pines, oaks, and aspen grow in the taiga,
but the region is also noted for such rare plants and trees as the
celebrated ginseng, the cork tree, the Greek nut tree, and the black
birch. Wild grape and ivy vines intertwine the upper branches of the
thick forest, and the trunks of the trees themselves rise from an almost
impenetrable maze of brush and downed timber.
So dense is the forest that in summer, a man can see no more than 10 or
12 feet in any direction. Yet in winter, the explorer’s lot is no
easier; for, although the deciduous trees then stand leafless, the
ground is covered by three feet or more of snow. And in the early fall,
violent cloudbursts often flood the taiga, making travel impossible.
Such was the inhospitable region in which the Ussuri, or (as it is now
known in the U.S.S.R.) Sikhote-Alin meteorite, had chanced to fall. For
any search parties traveling on the ground, the likelihood that they
could find the fallen meteorite in that wilderness would have been very
small.
The impact point of the Ussuri meteorite was discovered in the only way
really practical: from the air. Fortunately, the center of impact lay
almost directly below the airlane connecting the towns of Iman and
Ulunga, so that the devastation produced by the meteorite fall in the
taiga was clearly visible to aviators following this active air route.
The accounts several fliers gave concerning the widespread cratering and
destruction they had seen from the air in the impact area led to the
organization of two separate ground-search parties, one at Khabarovsk,
the other at Vladivostok. The Khabarovsk group, made up of four members
of the Geological Society, flew to the village of Kharkovo, the
inhabited point nearest the site of fall. After a rough and dangerous
landing on the small, snow-covered airfield at Kharkovo, the geologists
began their trek into the taiga on foot. Throughout the entire trip, the
men, burdened with supplies and equipment, waded through waist-deep snow
and camped in the open despite the arctic cold.
At almost the same time, a geologist from Vladivostok set out from the
railway line up the Ussuri valley to track down the fallen meteorite.
His progress was even more difficult than that of the Khabarovsk party.
In addition to following a much longer route, he did not have the
invaluable information that the first party had got from the aviators.
He had to make his way slowly from village to village, questioning
eyewitnesses as he went and gradually determining the probable end-point
of the meteorite fall.
[Illustration: COURTESY OF E. L. KRINOV
Splintered and broken trees at the site of the Ussuri fall.]
The route followed by the Vladivostok geologist lay through the heart of
the trackless snow-covered taiga. Fortunately, he had with him two
hunters who were well acquainted with the rigors of travel through the
taiga and knew how to live off the land.
They slept in hunters’ huts or under overhanging trees, drank melted
snow water, and ate fried quail. But they had not gone far when they
found that their footwear was completely useless for a trek through the
wet, snowy taiga, because their felt hiking boots quickly soaked up
water and became very heavy. So they swathed their feet in warm dry
grass over which they tied large pieces of untanned leather. After that,
the walking was much easier. They were able to cover the ground so
rapidly that they reached Kharkovo only a day after the Khabarovsk
geologists had landed there at the small airfield.
At Kharkovo, the three feasted on pork, milk, and honey. Then loading a
few provisions on a borrowed horse, they started out to overtake the
Khabarovsk party. They made such good time that the two groups were able
to join forces and to enter the impact area as one expedition, on
February 24, 1947.
A scene of great desolation awaited them in the central region of the
meteorite fall. Masses of crushed stone had been hurled hundreds of feet
by the violent impact. Denuded, uprooted trees lay about—some cut in two
as neatly as if by a saw. Large cedars had been splintered where they
stood or had been torn up by the roots and thrown some scores of yards.
[Illustration: COURTESY OF E. L. KRINOV
Workmen excavating one of the large craters formed by the impact of
the Ussuri meteorites.]
Most impressive of all, though, were the numerous meteorite craters
ranging in size from small bowl-like features to a basin more than 28
yards across and over 6 yards deep—a depression large enough to hold a
two-story house. The investigators recovered many fragments of the iron
meteorite that had broken to pieces not far above the earth’s surface
and had peppered the area of fall with high-speed meteoritic “shrapnel.”
With their meteorite recoveries and photographs of the cratered area,
the members of this first expedition returned to their respective towns
and began a campaign by letter and wire to interest the Moscow office of
the Academy of Sciences of the U.S.S.R. in making a full-scale
investigation of the Ussuri fall. The officials of the Academy decided
at once to send a special scientific expedition to the site of the
meteorite fall.
A member of this later and better-equipped expedition compared the
Ussuri crater field to a bombed-out area. In fact, some of the meteorite
specimens were fragments that closely resembled pieces of shattered
shell-casing. The edges of these fragments were jagged and bent, and
their surfaces, which often displayed a rainbow-colored sheen, were
grooved and scarred by impact against the hard rock underlying the
region in which the crater field had been formed. In rare instances, the
investigators noted spiral twisting of the fragments, an indication of
the unusually violent disruptive forces to which they had been subjected
at impact.
The scientists found several instances in which fist-sized meteorite
fragments had actually penetrated into or through standing tree trunks,
either becoming imbedded in the wood or driving a hole right through the
trunk.
[Illustration: COURTESY OF E. L. KRINOV
A nickel-iron meteorite from the Ussuri fall imbedded in the trunk
of a cedar tree.]
Many whole individual meteorites also were recovered. These were almost
always covered by a thin, smooth “glaze” known as _fusion crust_. This
crust forms on the surface of a meteorite as it plunges rapidly through
the air. The heat generated during its flight causes the outer “skin” of
the meteorite to melt. Later, when the mass has cooled off, the thin
coating of melted material hardens, forming a rind or crust.
By the beginning of 1951, the Russians had sent three more expeditions
to the site of the Ussuri fall. Their scientists found, in all, 122
craters (the largest more than 80 feet in diameter) as well as numerous
funnels resulting from the penetration of smaller meteorites into the
earth. By means of both visual and instrumental searches, they also
recovered 20,000 meteoritic fragments and individual meteorites. The
smallest Ussuri specimens weighed no more than the thousandth part of a
gram. (There are 453.59 grams in a pound.) Some of these tiny masses
were found lying cupped in leaves. The largest individual meteorite
recovered weighed about 3,839 pounds. Altogether, approximately 23 tons
of meteoritic material from the Ussuri fall are now in the collection of
the Meteorite Committee of the Academy of Sciences, Moscow, while
another 47 tons are believed to still be buried in the Ussuri crater
field.
[Illustration: COURTESY OF E. L. KRINOV
An individual Ussuri meteorite with fusion crust and characteristic
surface sculpturing produced during high-speed flight through the
resisting atmosphere.]
The Russian scientists carefully mapped the locations of the individual
craters, penetration funnels, and meteorite recoveries. They made
geologic and magnetometric surveys of the crater field, took aerial
photographs of the entire area of fall, and prepared a documentary
motion-picture covering the activities of the various expeditions. The
area of the crater field has been set aside by the Russian government as
a sort of scientific preserve, and is being made into the equivalent of
what is termed a National Monument in the U.S.A. Several of the typical
craters are protected by overroofed shelters to preserve these features
for generations yet to come.